Disclosure of Invention
Aiming at the problems of high conversion cost of the external energy storage PCS or system efficiency reduction caused by adding a DCDC converter in the prior art, the invention provides a high-voltage box suitable for a sodium ion energy storage system, a sodium ion energy storage system and a control method, which can not only avoid the existing external energy storage PCS replacement, but also avoid the system efficiency reduction problem. The specific technical scheme is as follows:
A high-voltage box suitable for a sodium ion energy storage system comprises a soft start circuit, a filter circuit, a Hall sensor, a voltage sensor, a main control BCM and a switch circuit, wherein the first positive end of the filter circuit is connected with the positive end of an external energy storage PCS, the first negative end of the filter circuit is connected with the negative end of the external energy storage PCS, the second positive end of the filter circuit is connected with the first end of the soft start circuit, the second end of the soft start circuit and the second negative end of the filter circuit are respectively connected with the first positive end and the first negative end of the switch circuit, the Hall sensor is connected in series between the second negative end of the filter circuit and the first negative end of the switch circuit, the second positive end of the switch circuit and the second negative end of the switch circuit are further arranged, the second positive end of the switch circuit is connected with the positive end of an external sodium ion battery PACK1, the second negative end of the switch circuit is connected with the negative end of the external sodium ion PACK1, the second negative end of the switch PACK is further arranged with the negative end of the external sodium ion battery PACK1, the second negative end of the switch circuit is further arranged with the third positive end of the switch circuit, the second negative end of the filter circuit is connected with the negative end of the external sodium ion battery PACK2, the main control PACK2 is connected with the negative end of the main control battery 2 in parallel, the sodium ion storage battery 2 is simultaneously, the positive end of the main control BCM and the sodium ion storage battery 2 is connected with the negative end of the main control battery 2 in parallel, the main control battery 2 is connected with the negative sodium ion storage battery 2, the current and voltage abrupt change generated by switching the external sodium ion batteries in different states in a serial-parallel connection mode is stabilized, the current and voltage abrupt change is smoothed, and the impact on the external energy storage PCS in the switching process is avoided.
Further, the switch circuit comprises a switch DCSSR1, a switch DCSSR and a switch DCSSR, wherein a first positive end of the switch circuit is directly led out to serve as a second positive end of the switch circuit, the first positive end of the switch circuit is connected with the switch DCSSR in series to serve as a third positive end of the switch circuit, a first negative end of the switch circuit is directly led out to serve as a third negative end of the switch circuit, the first negative end of the switch circuit is connected with the switch DCSSR in series to serve as a second negative end of the switch circuit, a switch DCSSR1 is connected between the second negative end of the switch circuit and the third positive end of the switch circuit in series, and the master control BCM is connected with the switch DCSSR, the switch DCSSR and the switch DCSSR to control the turn-off state of each switch.
Further, the switch circuit further comprises a NOT gate N1, wherein the input end of the NOT gate N1 is connected with the control end of the switch DCSSR and the control end of the switch DCSSR, the input end of the NOT gate N1 is connected with the main control BCM, and the output end of the NOT gate N1 is connected with the control end of the switch DCSSR 1.
Further, the filter circuit comprises a first LC circuit and a second LC circuit, and the first LC circuit and the second LC circuit are connected in parallel.
Further, the first LC circuit comprises a switch K11, a switch K12, an inductor L1 and a capacitor C1, the second LC circuit comprises a switch K21, a switch K22, an inductor L2 and a capacitor C2, the first end of the switch K11 is connected with the first end of the switch K12 and the first end of the inductor L1, the second end of the switch K12 is connected with the first end of the capacitor C1, the first end of the switch K21 is connected with the first end of the switch K22 and the first end of the inductor L2, the second end of the switch K22 is connected with the first end of the capacitor C2, the second end of the switch K11 is connected with the second end of the switch K21, the connecting point is used as the first positive end of the filter circuit, the second end of the inductor L1 is connected with the second end of the inductor L2, the second end of the capacitor C1 is connected with the second end of the capacitor C2, the second end of the capacitor C1 is used as the second positive end of the filter circuit, the second end of the capacitor C2 is used as the filter circuit, and the second end of the switch C2 is used as the negative end of the filter circuit, and the switch K can control the switch K and the filter circuit 11 and the second end of the filter circuit can be controlled to be in a grade state.
Further, the soft start circuit comprises a relay K31, a relay K32 and a resistor R31, wherein the first end of the relay K31 is connected with the first end of the resistor R31, the second end of the relay K31 is connected with the first end of the relay K32, the connecting point is used as the first end of the soft start circuit, the second end of the resistor R31 is connected with the second end of the relay K32, the connecting point is used as the second end of the soft start circuit, and the soft start circuit is used for switching on the relay K31 and the resistor R31 for pre-charging before formally switching on the relay K32 of the main passage, so that excessive impact on an external sodium ion battery is prevented.
The intelligent control device further comprises a first linkage circuit, wherein the first linkage circuit comprises an OR gate N2, a resistor R32 and a resistor R34, the first end of the resistor R32 is connected with the first end of the resistor R34, the connecting point is connected with the first input end of the OR gate N2, the second end of the resistor R34 is grounded, the second end of the resistor R32 is connected with the first end of the resistor R31, the second end input end of the OR gate N2 is connected with the main control BCM, and the output end of the OR gate N2 is connected with the switch K21 and the switch K22 respectively.
The second linkage circuit comprises a triode N3, a capacitor C3 and a resistor R33, wherein the collector of the triode N3 is connected with a power supply VCC, the base of the triode N3 is connected with the output end of the NOT gate N1, the emitter of the triode is connected with the first end of the capacitor C3, the second end of the capacitor C3 is connected with the first end of the resistor R33, the connection point of the second end of the capacitor C3 is connected with the third input end of the OR gate N2, and the second end of the resistor R33 is grounded.
The sodium ion energy storage system comprises the high-voltage box suitable for the sodium ion energy storage system, an external energy storage PCS, a slave BMM, an energy management system EMS, an external sodium ion battery PACK1 and an external sodium ion battery PACK2, wherein a first positive electrode end and a first negative electrode end of the filter circuit are respectively connected with the positive electrode end and the negative electrode end of the external energy storage PCS, a second positive electrode end and a second negative electrode end of the switch circuit are respectively connected with the positive electrode end and the negative electrode end of the external sodium ion battery PACK1, a third positive electrode end and a third negative electrode end of the switch circuit are respectively connected with the positive electrode end and the negative electrode end of the external sodium ion battery PACK2, and the master control BCM is respectively connected with the external energy storage PCS, the slave BMM and the energy management system EMS.
A sodium ion energy storage system control method for controlling the sodium ion energy storage system, comprising the following steps:
The high-voltage box is electrified for self-checking, the main control BCM performs serial-parallel switching on the external sodium ion battery PACK1 and the external sodium ion battery PACK2, and the serial-parallel voltage values are recorded;
When the series voltage value is larger than the maximum voltage of the direct current side of the external energy storage PCS and the parallel voltage is smaller than the maximum voltage of the direct current side of the external energy storage PCS, the main control BCM control switch DCSSR is turned off, the switch DCSSR and the switch DCSSR are turned on, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter a parallel voltage reduction mode;
When the series voltage value is larger than the minimum voltage of the direct current side of the external energy storage PCS and smaller than the maximum voltage of the direct current side of the external energy storage PCS, the main control BCM control switch DCSSR is turned on, the switch DCSSR and the switch DCSSR3 are turned off, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter a series operation boosting mode;
when the serial voltage value is smaller than the minimum voltage of the direct current side of the external energy storage PCS, the main control BCM sends a charge and discharge forbidden instruction to the external energy storage PCS and the energy management system EMS, and the total voltage undervoltage fault is reported;
Under the charging condition, after the main control BCM adjusts the serial or parallel connection mode of the external sodium ion battery PACK1 and the external sodium ion battery PACK2, the soft start circuit is controlled to carry out charging soft start in a mode of pre-charging and then formal charging so as to prevent impact damage of heavy current on the battery, and the serial and parallel connection adjustment is carried out according to the voltage condition of the battery;
Under the discharging condition, after the main control BCM adjusts the serial or parallel connection mode of the external sodium ion battery PACK1 and the external sodium ion battery PACK2, the soft start circuit is controlled to perform discharging soft start in a mode of pre-discharging and then formal discharging so as to prevent impact damage to the external energy storage PCS caused by heavy current, and the serial and parallel connection adjustment is performed according to the battery voltage condition.
Compared with the prior art, the invention has the beneficial effects that:
1. Based on the traditional high-voltage box, the device is based on the characteristic of wide voltage of the sodium ion energy storage battery and the requirements of uninterrupted power supply and rapid protection of an energy storage system. The high-voltage box takes a main control BCM as a control center, controls the on-off of a direct-current solid-state switch DCSSR according to collected battery state data, the running state of an energy storage system and an upper system control request, and realizes the high-low voltage nanosecond seamless switching of the battery cluster by matching with the conversion of the voltage and the current of an external energy storage PCS. Different LC circuit groups are configured to stabilize current and voltage abrupt changes generated by switching of external sodium ion batteries in different states in a serial-parallel mode, smooth the current and voltage abrupt changes, and avoid impact on external energy storage PCS in the switching process. On the premise that the existing external energy storage PCS converter is not changed, the high-voltage box with adjustable voltage is utilized to realize high-efficiency and low-cost seamless access of the sodium ion energy storage system with wide voltage range.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It will be understood that the terms "comprises" and "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this document, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It will be further understood that the term "and/or" as used in this document refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
Example 1
FIG. 1 is a schematic diagram of a high voltage tank suitable for a sodium ion energy storage system, comprising a soft start circuit, a filter circuit, a Hall sensor, a voltage sensor, a main control BCM and a switch circuit; the first positive electrode end of the filter circuit is connected with the positive electrode end of the external energy storage PCS; the first negative electrode end of the filter circuit is connected with the negative electrode end of an external energy storage PCS, the second positive electrode end of the filter circuit is connected with the first end of the soft start circuit, the second end of the soft start circuit and the second negative electrode end of the filter circuit are respectively connected with the first positive electrode end and the first negative electrode end of the switch circuit, the Hall sensor is connected in series between the second negative electrode end of the filter circuit and the first negative electrode end of the switch circuit, the switch circuit is further provided with the second positive electrode end and the second negative electrode end, the second positive electrode end of the switch circuit is connected with the positive electrode end of an external sodium ion battery PACK1, the second negative electrode end of the switch circuit is connected with the negative electrode end of the external sodium ion battery PACK1, the third positive electrode end of the switch circuit is further provided with the third positive electrode end and the third negative electrode end of the switch circuit, the third positive electrode of the switch circuit is connected with the positive electrode end of the external sodium ion battery PACK2, the third negative electrode of the switch circuit is connected with the negative electrode end of the external sodium ion battery PACK2, the voltage sensor is arranged between the first positive electrode end of the switch BCM and the first positive electrode end of the switch and the switch circuit, the BCM is connected with the external sodium ion battery PACK1 in parallel, the BCM and the negative electrode is connected with the external sodium ion battery PACK1 respectively, the switch battery PACK is controlled in parallel, meanwhile, the filtering capability level of the filtering circuit is adjusted according to the change of the serial-parallel connection state between the external sodium ion battery PACK1 and the external sodium ion battery PACK2, so that current and voltage abrupt changes generated by switching the external sodium ion battery in different states in a serial-parallel connection mode are stabilized, the current and voltage abrupt changes are smoothed, and impact on an external energy storage PCS in the switching process is avoided.
Because the voltage of the PCS direct current side of the energy storage converter is generally within 1200V of the withstand voltage of the MOS (metal-oxide-semiconductor field effect transistor) and the IGBT (insulated gate bipolar transistor) which are common nowadays, the full SOC voltage range of the sodium ion battery is 1.5V-4V, when the battery clusters are grouped by 334S, the voltage range of the battery clusters is 501-1336V, and the voltage range of the battery clusters exceeds the current PCS direct current side accessible voltage range of 1100V of the energy storage converter. When the battery clusters are grouped with less than 334S, the minimum voltage of the battery clusters is lower than the accessible voltage range of the PCS direct current side of the energy storage converter.
Therefore, the application is based on the characteristic of wide voltage of the sodium ion energy storage battery, uninterrupted power supply of the energy storage system and rapid protection requirements on the basis of the traditional high-voltage box. The high-voltage box takes a main control BCM as a control center, controls the on-off of a switch circuit according to collected battery state data, the running state of an energy storage system and an upper system control request, and realizes the high-low voltage nanosecond seamless switching of a battery cluster by matching with the conversion of external energy storage PCS voltage and current. Different LC circuit groups in the filter circuit are configured to stabilize current and voltage abrupt changes generated by switching of external sodium ion batteries in different states in a serial-parallel mode, smooth the current and voltage abrupt changes, and avoid impact on external energy storage PCS in the switching process. On the premise that the existing external energy storage PCS converter is not changed, the high-voltage box with adjustable voltage is utilized to realize high-efficiency and low-cost seamless access of the sodium ion energy storage system with wide voltage range.
In specific implementation, as shown in fig. 2, the switch circuit includes a switch DCSSR1, a switch DCSSR and a switch DCSSR, wherein a first positive terminal of the switch circuit is directly led out as a second positive terminal of the switch circuit, the first positive terminal of the switch circuit is connected in series with the switch DCSSR and then is used as a third positive terminal of the switch circuit, a first negative terminal of the switch circuit is directly led out as a third negative terminal of the switch circuit, the first negative terminal of the switch circuit is connected in series with a switch DCSSR and then is used as a second negative terminal of the switch circuit, a switch DCSSR is connected in series between the second negative terminal of the switch circuit and the third positive terminal of the switch circuit, and the master control BCM is connected with the switch DCSSR, the switch DCSSR and the switch DCSSR to control the turn-off state of each switch.
In specific implementation, the filter circuit comprises a first LC circuit and a second LC circuit, and the first LC circuit and the second LC circuit are connected in parallel.
In specific implementation, the first LC circuit comprises a switch K11, a switch K12, an inductor L1 and a capacitor C1, the second LC circuit comprises a switch K21, a switch K22, an inductor L2 and a capacitor C2, the first end of the switch K11 is connected with the first end of the switch K12 and the first end of the inductor L1, the second end of the switch K12 is connected with the first end of the capacitor C1, the first end of the switch K21 is connected with the first end of the switch K22 and the first end of the inductor L2, the second end of the switch K22 is connected with the first end of the capacitor C2, the second end of the switch K11 is connected with the second end of the switch K21, the connection point is used as the first positive end of the filter circuit, the second end of the inductor L1 is connected with the second positive end of the inductor L2, the second end of the capacitor C1 is connected with the second end of the capacitor C2, the second end of the capacitor C1 is used as the first negative end of the filter circuit, and the second end of the switch C2 is used as the second positive end of the filter circuit, and the second end of the switch K21 and the second end of the switch K can be controlled by the switch K and the switch K12 can be in a stage.
In specific implementation, the soft start circuit comprises a relay K31, a relay K32 and a resistor R31, wherein the first end of the relay K31 is connected with the first end of the resistor R31, the second end of the relay K31 is connected with the first end of the relay K32, the connecting point is used as the first end of the soft start circuit, the second end of the resistor R31 is connected with the second end of the relay K32, the connecting point is used as the second end of the soft start circuit, and the soft start circuit is used for switching on the relay K31 and the resistor R31 for pre-charging before formally switching on the relay K32 of the main passage so as to prevent overlarge impact on an external sodium ion battery.
Further, the external sodium ion batteries PACK1 and PACK2 are consistent in grouping mode, namely XPYS are connected in series, and the battery PACKs with X sodium ion batteries and Y sodium ion batteries connected in series are connected in parallel.
Further, the switch DCSSR, the switch DCSSR and the switch DCSSR can use MOS transistors or IGBT transistors, or other electronic components that can achieve the same, better switching performance.
Further, the switch K11, the switch K12, the switch K21 and the switch K22 may use MOS transistors or IGBT transistors, or may use relays, or other electronic components that can achieve the same switching function.
Further, each circuit is arranged on a circuit board, and the high-voltage box further comprises a shell, and the circuit board is arranged in the shell.
As shown in fig. 2,3, 5 and 6, a switch QF is arranged between the second positive terminal of the filter circuit and the first terminal of the soft start circuit, and a switch QF is arranged between the second negative terminal of the filter circuit and the hall sensor.
In the application, the soft start circuit realizes the flexible access of the high-voltage box, and the Hall sensor collects the current signal of the main loop of the high-voltage box. The battery main control BCM collects voltage and current signals of a main loop, receives BMM information of a battery auxiliary control, EMS information of an upper layer and PCS information of external energy storage and control signals, feeds back battery state information and control signals to the EMS of the upper layer and the PCS of external energy storage, carries out logic judgment according to the collected information and control signals, and controls the on-off of a soft start circuit relay, the on-off of a filter circuit switch group and the on-off of a switch circuit direct current solid switch DCSSR. Different LC circuit groups are configured in the filter circuit to stabilize current and voltage abrupt changes generated by switching of external sodium ion batteries in different states in a serial-parallel mode, smooth the current and voltage abrupt changes, and avoid impact on external energy storage PCS in the switching process. The main control BCM controls the on-off of the direct current solid switch DCSSR to realize the high-low voltage seamless switching of the battery cluster voltage in cooperation with the conversion of the external energy storage PCS voltage and current.
Example two
As shown in fig. 3, the difference between the present embodiment and the first embodiment is that the switching circuit further includes a not gate N1, an input end of the not gate N1 is connected to a control end of the switch DCSSR and a control end of the switch DCSSR, an input end of the not gate N1 is connected to the master control BCM, and an output end of the not gate N1 is connected to a control end of the switch DCSSR 1. The series mode and the parallel mode of the battery can be interlocked through the NOT gate N1, namely the parallel mode cannot occur when the series mode is used, and the series mode cannot occur when the parallel mode is used, so that the short circuit between the battery and the external energy storage PCS caused by the simultaneous full conduction of the switch DCSSR, the switch DCSSR2 and the switch DCSSR due to the failure of the main control BCM or the error of signal output setting is prevented, and the safety performance of the circuit is improved.
The implementation method comprises the steps of enabling a first linkage circuit to be further included, enabling the first linkage circuit to comprise an OR gate N2, a resistor R32 and a resistor R34, enabling a first end of the resistor R32 to be connected with a first end of the resistor R34, enabling a connection point to be connected with a first input end of the OR gate N2, enabling a second end of the resistor R34 to be grounded, enabling a second end of the resistor R32 to be connected with a first end of the resistor R31, enabling an input end of a second end of the OR gate N2 to be connected with a main control BCM, and enabling an output end of the OR gate N2 to be connected with a switch K21 and a switch K22 respectively.
The first linkage circuit is used for linking the soft start circuit and the filter circuit, so that:
and the soft start circuit can gradually increase current when the system is started, so that abrupt high current impact is avoided. The filter circuit can further smooth the current, reducing ripple and spikes of the current.
And the protection circuit can effectively reduce current impact during starting through the linkage of the soft start circuit and the filter circuit, and protects other elements in the circuit, such as a capacitor, an inductor and a semiconductor device.
The system stability is improved, namely the linkage of the soft start circuit and the filter circuit can ensure smoother current and voltage change when the system is started, and the system oscillation and instability phenomena are reduced.
In the implementation, the circuit further comprises a second linkage circuit, wherein the second linkage circuit comprises a triode N3, a capacitor C3 and a resistor R33, the collector of the triode N3 is connected with a power supply VCC, the base of the triode N3 is connected with the output end of the NOT gate N1, the emitter of the triode is connected with the first end of the capacitor C3, the second end of the capacitor C3 is connected with the first end of the resistor R33, the connection point of the triode C3 and the resistor R33 is connected with the third input end of the OR gate N2, and the second end of the resistor R33 is grounded.
The second linkage circuit can be used for linkage of the switching circuit and the filter circuit:
The current distribution is optimized, namely the switch circuit controls the connection mode (parallel connection or series connection) of the battery pack, and the filter circuit can smooth the current change during the switching of the switch circuit, so that the current distribution is optimized.
And the current impact is reduced, namely when the switching circuit is switched, the corresponding filter circuit capacity level (such as higher series cut-in voltage and dynamic tuning of two LC circuits) is adapted, the abrupt change of the current can be reduced, and the impact on an energy storage system and a PCS (power conversion system) is avoided.
The system response speed is improved, namely the change of the system state can be responded more quickly through the linkage of the switch circuit and the filter circuit, and the dynamic performance of the system is improved.
Meanwhile, the application adopts the linkage effect realized by the hardware circuit, can improve the anti-interference capability and the fault tolerance capability, prevents the linkage failure problem caused by the fault of the upper controller, and does not influence the linkage protection effect even if the main control BCM breaks down.
Therefore, the system reliability is improved through the linkage circuit, the system reliability and stability can be remarkably improved through the linkage of the soft start circuit and the filter circuit and the linkage of the switch circuit and the filter circuit, and the probability of fault occurrence is reduced. The service life of the device can be prolonged, current impact and voltage fluctuation are reduced, and the service lives of the battery pack, the capacitor, the inductor and other key elements can be prolonged. Meanwhile, the system performance is optimized, the overall performance of the system can be optimized through smoothing current and voltage changes, the energy conversion efficiency is improved, and the energy loss is reduced. The anti-interference capability and fault tolerance capability of the system are also improved. The stability and the reliability of the energy storage system can be obviously improved, the current impact and the voltage fluctuation are reduced, the system performance is optimized, and the service life of equipment is prolonged. These improvements are important to improve the overall performance and safety of the energy storage system.
Example III
The sodium ion energy storage system comprises the high-voltage box suitable for the sodium ion energy storage system, an external energy storage PCS, a slave BMM, an energy management system EMS, an external sodium ion battery PACK1 and an external sodium ion battery PACK2, wherein a first positive electrode end and a first negative electrode end of a filter circuit are respectively connected with the positive electrode end and the negative electrode end of the external energy storage PCS, a second positive electrode end and a second negative electrode end of a switch circuit are respectively connected with the positive electrode end and the negative electrode end of the external sodium ion battery PACK1, a third positive electrode end and a third negative electrode end of the switch circuit are respectively connected with the positive electrode end and the negative electrode end of the external sodium ion battery PACK2, and a master control BCM is respectively connected with the external energy storage PCS, the slave BMM and the energy management system EMS.
Example IV
A sodium ion energy storage system control method for controlling the sodium ion energy storage system, comprising the following steps:
The high-voltage box is electrified for self-checking, the main control BCM performs serial-parallel switching on the external sodium ion battery PACK1 and the external sodium ion battery PACK2, and the serial-parallel voltage values are recorded;
When the series voltage value is larger than the maximum voltage of the direct current side of the external energy storage PCS and the parallel voltage is smaller than the maximum voltage of the direct current side of the external energy storage PCS, the main control BCM control switch DCSSR is turned off, the switch DCSSR and the switch DCSSR are turned on, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter a parallel voltage reduction mode;
When the series voltage value is larger than the minimum voltage of the direct current side of the external energy storage PCS and smaller than the maximum voltage of the direct current side of the external energy storage PCS, the main control BCM control switch DCSSR is turned on, the switch DCSSR and the switch DCSSR3 are turned off, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter a series operation boosting mode;
when the serial voltage value is smaller than the minimum voltage of the direct current side of the external energy storage PCS, the main control BCM sends a charge and discharge forbidden instruction to the external energy storage PCS and the energy management system EMS, and the total voltage undervoltage fault is reported;
Under the charging condition, after the main control BCM adjusts the serial or parallel connection mode of the external sodium ion battery PACK1 and the external sodium ion battery PACK2, the soft start circuit is controlled to carry out charging soft start in a mode of pre-charging and then formal charging so as to prevent impact damage of heavy current on the battery, and the serial and parallel connection adjustment is carried out according to the voltage condition of the battery;
Under the discharging condition, after the main control BCM adjusts the serial or parallel connection mode of the external sodium ion battery PACK1 and the external sodium ion battery PACK2, the soft start circuit is controlled to perform discharging soft start in a mode of pre-discharging and then formal discharging so as to prevent impact damage to the external energy storage PCS caused by heavy current, and the serial and parallel connection adjustment is performed according to the battery voltage condition.
That is, the total voltage Vp1 of the external sodium ion battery PACK1 and the total voltage Vp2 of the external sodium ion battery PACK2 are set to Vp2.
When Vp1+Vp2 > PCS DC side maximum voltage Vmax and Vp1< Vmax & Vp2< Vmax, master BCM control DCSSR1 is open, switch DCSSR2 and switch DCSSR are conductive, PACK1 and PACK2 enter parallel buck mode, as in FIG. 6. At the moment, the main control BCM controls the switches K11, K12, K21 and K22 to be attracted, and the relay K31 and the relay K32 of the soft start circuit are controlled to be attracted sequentially to connect the external sodium ion battery to the direct current side of the PCS.
When the master BCM detects that the minimum voltage Vmin is less than or equal to Vp1+Vp2 is less than or equal to Vmax on the PCS DC side, the master BCM control DCSSR is turned on, DCSSR and DCSSR3 are turned off, and PACK1 and PACK2 enter a series operation boost mode, as shown in FIG. 5. The main control BCM controls the switches K11, K12, K21 and K22 to be attracted, and the relay K31 and the relay K32 of the soft start circuit are controlled to be attracted sequentially to connect the external sodium ion battery to the direct current side of the PCS.
When the main control BCM detects that Vmin is smaller than Vp1+Vp2, the main control BCM sends a charge and discharge forbidden instruction to the PCS and the EMS, and the total voltage under-voltage fault is reported.
In the charging process, any single voltage Vc in the energy storage system is more than or equal to 4.0V (the single-cell maximum voltage can be obtained by setting a voltage detection circuit or a sensor for each single cell and feeding back a signal to a main control BCM), or Vp1 is more than or equal to Vmax, or Vp2 is more than or equal to Vmax, and the BCM sends a charge forbidden instruction to the PCS and the EMS.
In the discharging process, when Vp1 is less than or equal to Vmin or Vp2 is less than or equal to Vmin and any monomer voltage Vc in an energy storage system is more than 1.5V, the main control BCM controls K11 and K12 to be attracted, controls K21 and K22 to be disconnected, controls DCSSR to be turned on after T1 time and controls DCSSR and DCSSR3 to be disconnected, the voltage of a battery cluster is doubled after switching, the current is doubled, the phenomenon that a PCS device is damaged due to voltage sudden increase and current sudden drop easily occurs, the first LC circuit of a high-voltage box is used for stabilizing the current after switching, and the BCM sends instructions after switching to enable the PCS voltage to be doubled and the current to be doubled so as to adapt to the sudden change of the voltage and the current of the battery cluster, and PACK1 and PACK2 enter a series boosting mode seamlessly. If the voltage Vc of any monomer in the energy storage system is less than or equal to 1.5V, the BCM sends a forbidden instruction to the PCS and the EMS. The T1 time is an interval time set according to actual needs.
In the discharging process, when the voltage Vc of any monomer in the energy storage system is less than or equal to 1.5V or Vp1+Vp2 is less than or equal to Vmin, the BCM sends a discharging prohibition instruction to the PCS and the EMS.
In the charging process, vp1+Vp2 is larger than or equal to Vmax, when any monomer voltage Vc in an energy storage system is smaller than 4V, BCM controls K11 and K12 to be disconnected, K21 and K22 to be attracted, T2 controls DCSSR to be conducted, DCSSR and DCSSR3 to be disconnected, voltage of a battery cluster is reduced by one time and current is doubled after switching, a PCS device is extremely easy to be damaged due to voltage drop and current surge, a high-voltage box second LC circuit is used for stabilizing current follow current and voltage after switching, BCM sends instructions after switching to enable PCS voltage to be reduced by one time and current to be doubled so as to adapt to voltage and current mutation of the battery cluster, and PACK1 and PACK2 enter a parallel voltage dropping mode in a seamless mode. If the voltage Vc of any monomer in the energy storage system is more than or equal to 4V, or Vp1 is more than or equal to Vmax, or Vp2 is more than or equal to Vmax, BCM sends a charge forbidden instruction to PCS and EMS. The T2 time is an interval time set according to actual needs.
The high-voltage box can realize that the sodium ion energy storage system with a wide voltage range is connected to the conventional PCS converter, DCDC (direct current) is not required to be configured or a higher voltage platform power device is not required to be used, and the high-voltage box has the characteristics of low cost, high efficiency, high switching speed and high reliability.
In applications where seamless switching is not required or switching time is not required, conventional circuit breakers, contactors, etc. may be used in place of the dc solid state switches DCSSR.
The application provides a high-voltage box suitable for a sodium ion energy storage system, which comprises a soft start circuit, a filter circuit, a Hall sensor, a voltage sensor, a main control BCM and a switch circuit, wherein the soft start circuit is connected with the filter circuit; the first positive electrode end of the filter circuit is connected with the positive electrode end of the external energy storage PCS; the first negative pole end of the filter circuit is connected with the negative pole end of an external energy storage PCS, the second positive pole end of the filter circuit is connected with the first end of the soft start circuit, the second end of the soft start circuit and the second negative pole end of the filter circuit are respectively connected with the first positive pole end and the first negative pole end of the switch circuit, the Hall sensor is connected in series between the second negative pole end of the filter circuit and the first negative pole end of the switch circuit, the second positive pole end and the second negative pole end are further arranged on the switch circuit, the second positive pole end of the switch circuit is connected with the positive pole end of an external sodium ion battery PACK1, the second negative pole end of the switch circuit is connected with the negative pole end of the external sodium ion battery PACK1, the third positive pole end of the switch circuit is further arranged with the positive pole end of the external sodium ion battery PACK2, the third negative pole end of the switch circuit is connected with the negative pole end of the external sodium ion battery PACK2, the voltage sensor is arranged between the first positive pole end of the switch and the negative pole end of the switch circuit, the filter circuit is connected with the external sodium ion battery PACK1 in parallel, the filter circuit can be adjusted in parallel, and the state of the filter circuit can be adjusted according to the serial connection between the first positive pole end of the BCM and the negative pole end of the filter circuit and the external sodium ion battery PACK1, the current and voltage abrupt change generated by switching the external sodium ion batteries in different states in a serial-parallel connection mode is stabilized, the current and voltage abrupt change is smoothed, and the impact on the external energy storage PCS in the switching process is avoided. Based on the traditional high-voltage box, the device is based on the characteristic of wide voltage of the sodium ion energy storage battery and the requirements of uninterrupted power supply and rapid protection of an energy storage system. The high-voltage box takes a main control BCM as a control center, controls the on-off of a switch circuit according to collected battery state data, the running state of an energy storage system and an upper system control request, and realizes the high-low voltage nanosecond seamless switching of a battery cluster by matching with the conversion of external energy storage PCS voltage and current. Different LC circuit groups in the filter circuit are configured to stabilize current and voltage abrupt changes generated by switching of external sodium ion batteries in different states in a serial-parallel mode, smooth the current and voltage abrupt changes, and avoid impact on external energy storage PCS in the switching process. On the premise that the existing external energy storage PCS converter is not changed, the high-voltage box with adjustable voltage is utilized to realize high-efficiency and low-cost seamless access of the sodium ion energy storage system with wide voltage range.
Those of ordinary skill in the art will appreciate that the elements of the examples described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the elements of the examples have been described generally in terms of functionality in the foregoing description to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in the present invention, it should be understood that the division of the units is merely a logic function division, and there may be other division manners in actual implementation, for example, multiple units may be combined into one unit, one unit may be split into multiple units, or some features may be omitted.
In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied essentially or in part or all of the technical solution or in part in the form of a software product stored in a storage medium, including instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. The storage medium includes a U disk, a Read-only memory (ROM, read-0 nlyMemory), a random access memory (RAM, randomAccessMemory), a removable hard disk, a magnetic disk, or an optical disk, etc. which can store the program codes.
It should be noted that the foregoing embodiments are merely illustrative of the technical solutions of the present invention and not limiting, and although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions described in the foregoing embodiments may be modified or some or all of the technical features may be equivalently replaced, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and are all included in the scope of the present invention.