Disclosure of Invention
The invention aims to provide a high-voltage wide-voltage-range input power supply DC-DC converter and a control method thereof, so as to realize the diversity of voltage and/or current modes, meet the requirements of users and improve the use experience of the users.
The technical solution for realizing the purpose of the invention is as follows:
in a first aspect, embodiments of the present application provide a high voltage wide voltage range input power DC-DC converter, comprising:
the system comprises a signal acquisition module, a power supply module, a protection module and a microcontroller;
the signal acquisition module is connected with the power supply module and used for acquiring output voltage and output current in the power supply module and sending the output voltage and the output current to the microcontroller;
the microcontroller is connected with the signal acquisition module and is used for receiving the output voltage and the output current sent by the signal acquisition module and sending the output voltage and the output current to the protection module; the power supply module is also in wireless connection with remote control equipment and is further used for responding to receiving target voltage and/or target current sent by the remote control equipment and sending the target voltage and/or the target current to the power supply module;
the protection module is connected with the microcontroller and the power supply module and is used for receiving the output voltage, the output current, the target current and/or the target voltage sent by the microcontroller and sending the output voltage, the output current, the target current and/or the target voltage to the power supply module;
the power module is connected with the protection module and comprises a half-bridge driving circuit, and the half-bridge driving circuit is used for adjusting the conduction time and the switching frequency of the MOS tube in the half-bridge driving circuit according to the target voltage and/or the target current so that the output voltage of the power module is the target voltage and/or the output current of the power module is the target current.
Optionally, the high-voltage wide-voltage-range input power DC-DC converter further includes: and the auxiliary power supply module is respectively connected with the signal acquisition module and the microcontroller and is used for providing power for the signal acquisition module and the microcontroller.
Optionally, the signal acquisition module includes: a voltage dividing circuit, an amplifying circuit and a filter circuit;
the voltage dividing circuit, the amplifying circuit and the filter circuit are connected in series;
the output end of the voltage dividing circuit is connected with the input end of the amplifying circuit, and the output end of the amplifying circuit is connected with the input end of the filtering circuit.
Optionally, the power module includes: the device comprises a PI control circuit, a PWM control chip, a transformer and a drive IC;
the driving IC is used for driving the MOS tube of the half-bridge driving circuit on the primary side of the transformer to be conducted when the PWM control chip is in a working state so as to enable the secondary side of the transformer to be in a working state;
the PI control circuit is arranged on the secondary side of the transformer and connected with the PWM control chip, and is used for determining feedback voltage according to the target voltage and the output voltage when the secondary side of the transformer is in a working state; and/or determining a feedback current from the target current and the output current; transmitting the feedback voltage and/or the feedback current to the PWM control chip;
the PWM control chip is arranged on the secondary side of the transformer, an error amplifier is arranged in the PWM control chip and used for receiving the feedback voltage and/or the feedback current sent by the PI control circuit, driving the error amplifier to work, and adjusting the duty ratio and the frequency of an output PWM waveform so as to adjust the conduction time and the switching frequency of the MOS tube in the half-bridge driving circuit.
Optionally, the power module further includes an RC filter circuit connected to a pin of the PWM control chip, for protecting the EMC module from interference.
Optionally, the power module further includes a reverse diode connected to the MOS transistor on the secondary side of the transformer, and configured to bleed the voltages of the source and the gate from the MOS transistor when the transformer is not in the working state.
Optionally, the power module further includes an RCD reset circuit, which is respectively connected to the primary side and the secondary side of the transformer, and is configured to bleed leakage inductance energy of the transformer.
Optionally, the power module further includes: and the synchronous rectification circuit is arranged on the secondary side of the transformer and is used for reducing loss.
Optionally, the protection module includes: an EMC module;
the input end of the EMC module is provided with a one-stage LC filter circuit and a two-stage pi-type filter circuit which are used for attenuating differential mode and common mode interference signals of different frequency bands;
and the output end of the EMC module is provided with a first-stage pi-type filter circuit for inhibiting the high-frequency common-mode interference signal.
In a second aspect, an embodiment of the present application provides a control method for a DC-DC converter of a high-voltage wide-voltage-range input power supply, including:
the system comprises a signal acquisition module, a power supply module, a protection module and a microcontroller;
the power supply module comprises a half-bridge driving circuit;
responsive to receiving a target voltage and/or a target current sent by a remote control device, collecting an output voltage and/or an output current of the DC-DC converter;
and according to the target voltage and/or the target current, adjusting the conduction time and the switching frequency of the MOS tube of the half-bridge driving circuit so that the output voltage of the power supply module is the target voltage and/or the output current of the power supply module is the target current.
In the technical scheme, the high-voltage wide-voltage-range input power supply DC-DC converter comprises a signal acquisition module, a power supply module, a protection module and a microcontroller, wherein the power supply module comprises a half-bridge driving circuit, so that the vehicle-mounted power supply DC-DC converter can realize different voltage and current modes based on the requirements of users, different voltage and/or current requirements can be realized for different users, the high-voltage wide-voltage-range input power supply DC-DC converter has the advantage of high-voltage wide-voltage-range input, and the power consumption requirements of the users are met. In addition, the vehicle-mounted power supply DC-DC converter adopts various protection measures, and the reliability of the high-voltage wide-voltage-range input power supply DC-DC converter is improved.
Detailed Description
The principle of the invention is as follows: the high-voltage wide-voltage-range input power supply DC-DC converter comprises a signal acquisition module, a power supply module, a protection module and a microcontroller, wherein the power supply module comprises a half-bridge driving circuit, so that the high-voltage wide-voltage-range input power supply DC-DC converter can realize different voltage and current modes based on the requirements of users, different voltage and/or current requirements can be realized for different users, the power consumption requirements of the users are met, and the use experience of the users is improved. In addition, the high-voltage wide-voltage-range input power supply DC-DC converter adopts various protection measures, and the reliability of the vehicle-mounted power supply DC-DC converter is improved.
In this embodiment, a high-voltage wide-voltage-range input power DC-DC converter is provided, fig. 1 is a block diagram of a vehicle-mounted power DC-DC converter provided in an embodiment of the present application, and as shown in fig. 1, the high-voltage wide-voltage-range input power DC-DC converter may include:
a signal acquisition module 200, a power module 300, a protection module 400, and a microcontroller 100;
the signal acquisition module 200 is connected with the power supply module 300, and is used for acquiring output voltage and output current in the power supply module 300 and sending the output voltage and the output current to the microcontroller 100;
the microcontroller 100 is connected with the signal acquisition module 200, and is used for receiving the output voltage and the output current sent by the signal acquisition module 200 and sending the output voltage and the output current to the protection module 400; is also wirelessly connected to the remote control device 600 and is further configured to send a target voltage and/or a target current to the protection module 400 in response to receiving the target voltage and/or the target current sent by the remote control device;
a protection module 400 connected to the microcontroller 100 and the power module 300 for transmitting to the power module 300 in response to receiving the output voltage, the output current, the target current and/or the target voltage transmitted from the microcontroller 100; the power module 300 is further configured to compare the output voltage and the output current with a preset voltage threshold and a preset current threshold, respectively, and determine whether an overvoltage and/or overcurrent condition exists in the power module 300; if the power module 300 has overvoltage and/or overcurrent conditions, performing overvoltage protection and/or overcurrent protection on the power module 300;
the power module 300 is connected with the protection module 400, and the power module 300 comprises a half-bridge driving circuit for adjusting the on time and the switching frequency of the MOS tube in the half-bridge driving circuit according to the target voltage and/or the target current, so that the output voltage of the power module 300 is the target voltage and/or the output current of the power module 300 is the target current.
The DC-DC converter may output a fixed Voltage in a Constant Voltage mode (CV) alone, may output a fixed current in a Constant current mode (CC) alone, may output a Constant current in a Constant current mode (CC) alone, and may switch between the CC mode and the CV mode independently. Wherein the target voltage, and the target current have different gear modes. The input voltage of the DC-DC converter may be 300 to 1000V, and the output voltage of the DC-DC converter may be a fixed value of 12V or 9 to 16V. Thus, the target voltage for user selection may be 9V, 12V, 15V, 16V, etc., and may be adjusted in steps of 0.15V. The input current of the DC-DC converter can be 0.5A, and the output current of the DC-DC converter can be 1A-25A, so that voltages which can be selected by a user are 1A, 5A, 10A, 15A, 25A and the like, and the step size 1A can be adjusted. The output power of the DC-DC converter may be 300W. The overall construction size of the DC-DC converter may range from 120mm by 80mm by 35mm. The user can set the target voltage of the DC-DC converter alone by the remote control device, can set the target current of the DC-DC converter alone, and can set the target voltage and the target current of the DC-DC converter at the same time.
The remote control device may include a remote control and switch keys. When the remote control device sends the target voltage and/or the target current set by the user, as shown in fig. 2, which is a schematic diagram of the microcontroller 100, a path of CAN bus (Controller Area Network, controller area network bus) is provided in the microcontroller 100, and communication between the DC-DC converter and the remote control device CAN be implemented through the CAN bus in the microcontroller 100, so as to receive the target voltage and/or the target current. Meanwhile, the remote control equipment CAN also set the working mode of the DC-DC converter through the CAN bus, when the remote control equipment sends a DC-DC converter enabling signal, the DC-DC converter CAN enter a normal working mode, and the target voltage and the target current of the DC-DC converter are switched between different gears by the remote control equipment.
In order to ensure power consumption of the DC-DC converter, power-off sleep is used when the DC-DC converter is dormant. At this time, the pin 7 of the CAN chip is in a low potential, the pin 14 is in a low level state, and the whole system is in a dormant state; after the DC-DC converter enters a dormant state, an external controller CAN send a message through a CAN bus to enable the 7 pin to become high potential, the system is electrified, the MCU works, and the 14 pin is pulled high, so that the DC-DC converter is awakened.
In the technical scheme, the high-voltage wide-voltage-range input power supply DC-DC converter comprises a signal acquisition module, a power supply module, a protection module and a microcontroller, wherein the power supply module comprises a half-bridge driving circuit, so that the high-voltage wide-voltage-range input power supply DC-DC converter can realize different voltage and current modes based on the requirements of users, different voltage and/or current requirements can be realized for different users, the power consumption requirements of the users are met, and the use experience of the users is improved. In addition, the high-voltage wide-voltage-range input power supply DC-DC converter adopts various protection measures, and the reliability of the vehicle-mounted power supply DC-DC converter is improved.
As shown in fig. 3, the high-voltage wide-voltage-range input power DC-DC converter further includes: the auxiliary power supply module 500 is respectively connected with the signal acquisition module 200 and the microcontroller 100, and is used for providing power for the signal acquisition module 200 and the microcontroller 100.
As shown in fig. 4, the auxiliary power module 500 is processed in the following manner: after being input by a 12V external power supply, the power is converted into direct current of 5V through BUCK, and then the direct current is divided into two paths, one path is reduced in voltage and converted into 3.3V through LDO for being used by a DSP module, and the other path is converted into power of +16V and-4V for being used by the microcontroller 100 and the signal acquisition module 200 after being driven and isolated through a transformer in a driving power supply module.
The voltage-reducing circuit selected in this time is a BUCK circuit as shown in fig. 5 for the 12V power input part, and the BUCK circuit is used to ensure that the conversion efficiency of the circuit reaches more than 95% because the later stage 5V needs to output a large current of 2A. The BUCK chip selected at this time is LM2576S-5.0, has very small size, integrates an internal inductor and an internal switching circuit, and can output large current more than 3A. The 12V input power supply requires an external 12V hard-wire wake-up signal to turn on the MOS Q7, thereby enabling the control circuit to enter a standby state.
As shown in fig. 6, the driving power supply module is mainly provided by a transformer driving chip driving isolation transformer, and because the on voltage of the MOS transistor is only about 2V, in order to avoid misleading of the MOS transistor caused by external interference, the GS power supply of the MOS transistor adopts positive and negative power supplies. The circuit principle is that a push-pull voltage is provided for a transformer driving chip at the primary side of the transformer, the voltage is raised to 20V through the turn ratio of the transformer, then the voltage at the C78 end is stabilized at 4V through a TL431 voltage stabilizing chip, and when 0V-V1 is used as a ground wire, the DC-IN-voltage is-4V. The method for manufacturing the negative voltage is low in cost and small in volume relative to two transformer windings, and the provided negative voltage can be adjusted at any time according to requirements, so that the negative voltage is very stable.
As shown in FIG. 7, the 12V BUCK is reduced to 5V and then connected with a first-stage LDO for analog power supply, and the LDO has a very high ripple rejection ratio and can provide up to 0.5% of power supply precision. However, since the LDO is input into the linear voltage stabilizing device, the input is about 2V higher than the output to work normally,
as shown in fig. 8, the signal acquisition module 200 includes: the circuit comprises a voltage dividing circuit, an amplifying circuit and a filtering circuit;
the voltage dividing circuit, the amplifying circuit and the filter circuit are connected in series;
the output end of the voltage dividing circuit is connected with the input end of the amplifying circuit, and the output end of the amplifying circuit is connected with the input end of the filtering circuit.
As shown in fig. 8 (a), when the primary voltage of the transformer is collected, in order to ensure electrical isolation, the primary voltage is divided and isolated by an isolation amplifier, and the output of the isolation amplifier is a differential signal, so that the differential signal is converted into a single-ended signal by an operational amplifier and then connected to the microcontroller 100 for detection.
As shown in fig. 8 (b) and 8 (c), the output voltage of the power module 300 is collected, that is, the secondary side voltage of the transformer is collected, and the secondary side does not need to be isolated, so that after the voltage is divided, the current signal is small, so that the current signal is amplified to ensure the detection precision, and the amplified signal can be connected to the microcontroller 100 for detection through the filter circuit.
As shown in fig. 9, the power module 300 includes: the device comprises a PI control circuit, a PWM control chip, a transformer and a drive IC;
the driving IC is used for driving the MOS tube of the half-bridge driving circuit on the primary side of the transformer to be conducted when the PWM control chip is in a working state so as to enable the secondary side of the transformer to be in a working state;
the PI control circuit is arranged on the secondary side of the transformer and connected with the PWM control chip, and is used for determining feedback voltage according to target voltage and output voltage when the secondary side of the transformer is in a working state; and/or determining a feedback current according to the target current and the output current; transmitting the feedback voltage and/or feedback current to the PWM control chip;
the PWM control chip is arranged on the secondary side of the transformer, an error amplifier is arranged in the PWM control chip and used for receiving feedback voltage and/or feedback current sent by the PI control circuit, driving the error amplifier to work, and regulating the duty ratio and frequency of an output PWM waveform so as to regulate the conduction time and the switching frequency of the MOS tube in the half-bridge driving circuit.
When the 12V-side is connected with a power supply, the PWM control chip starts to work, the isolation drive IC drives the primary side high-voltage side half-bridge MOS tube to conduct in a phase shift mode by 180 degrees, and when the MOS tube is conducted, the transformer transmits primary side voltage to the secondary side, energy is stored through the inductor and the secondary side load is driven to work. When the primary side high-voltage MOS is turned off, the energy stored by the secondary side inductor is released to the load to maintain the load voltage. The half-bridge is alternately conducted to generate frequency multiplication on the secondary side inductor, so that the switching frequency of 50kHZ of the primary side high-voltage MOS can generate 100kHZ of the switching frequency on the inductor, the volume of the inductor is reduced, and the switching loss of the primary side MOS tube is reduced. Since the half-bridge transformer only transmits energy, the transformer volume is correspondingly reduced.
The upper bridge arm and the lower bridge arm of the half bridge can realize automatic power balance without an additional balance circuit. When the voltage of the upper half bridge arm is higher than that of the lower half bridge arm, the output voltage of the secondary side is increased, the output current of the secondary side is also increased, the power of the upper half bridge arm of the primary side is higher than that of the lower half bridge arm, and the voltage of the upper half bridge arm is reduced. In order to prevent the transformer from magnetic saturation, and simultaneously in order to realize short-circuit protection, a current transformer is directly connected to an OFF pin of the PWM control chip on the primary side, and when the current of the primary side is overlarge, the short-circuit protection is immediately triggered to turn OFF the PWM control chip.
In order to output set output voltage and current, voltage and current collection is added to the secondary side output part of the transformer, voltage and current values of the secondary side are collected in real time, the collected voltage and current values are transmitted to the PI control circuit, the PI control circuit determines feedback voltage and feedback current according to target voltage and target current, so that an error amplifier in a PWM control chip is driven to work, the duty ratio and frequency of a waveform of PWM output are controlled, the conduction time and switching frequency of an MOS tube in the half-bridge driving circuit are adjusted, and the purpose of adjusting the output voltage and the output current is achieved. In order to ensure that the system is not interfered by EMC, an RC circuit is connected to a feedback pin of the FB for filtering, so that the output of the system is more stable.
Because the PWM control chip is positioned at the secondary side and cannot directly drive the primary side high-voltage MOS, the primary side MOS tube is driven by adopting an isolation driving IC mode, the two pins A and B of the driving chip are conducted in 180-degree phase shift, voltage is generated at the primary side of the transformer, the transformer transmits the voltage to the secondary side, and the MOS tube is driven to work.
As shown in fig. 9, the power module 300 further includes an RC filter circuit connected to the FB pin of the PWM control chip for protecting the EMC module from interference.
As shown in fig. 9, the power module 300 further includes a reverse diode connected to the MOS transistor on the secondary side of the transformer, and configured to bleed the voltages of the source and the gate from the MOS transistor when the transformer is not in the operating state.
In order to ensure that the source and grid voltages can be quickly released when the MOS transistor is not in a working state of the transformer, a reverse diode is added to quickly release.
As shown in fig. 9, the power module 300 further includes an RCD reset circuit connected to the primary side and the secondary side of the transformer, respectively, for discharging leakage inductance energy of the transformer.
Leakage inductance is inevitably generated when the transformer is wound, when the MOS tube is turned off, energy on the leakage inductance of the transformer cannot be released, oscillation can be generated with output parasitic capacitance of the MOS tube, higher voltage is caused at the drain electrode D and the source electrode S end of the MOS tube, the MOS tube breaks down, and if the energy on the leakage inductance is not reset, accumulated energy can also cause magnetic saturation of the transformer. Therefore, an RCD reset circuit is set to discharge leakage inductance energy of the transformer.
As shown in fig. 9, the power module 300 further includes: and the synchronous rectification circuit is arranged on the secondary side of the transformer and used for reducing the loss caused by the output diode.
The DC-DC converter is required to operate in a high-current and high-efficiency state, synchronous rectification control is adopted for output in order to solve the loss caused by an output diode, synchronous rectification is possibly conducted by mistake due to output oscillation in a DCM mode (Discontinuous Conduction Mode ), and therefore the flicker time Tblk is set on the synchronous rectification controller, so that the synchronous rectification tube can operate reliably.
As shown in fig. 10, the protection module 400 includes: an EMC module;
as shown in fig. 10 (a), the input end of the EMC module is provided with a one-stage LC filter and a two-stage pi-type filter circuit for attenuating differential mode and common mode interference signals in different frequency bands;
as shown in fig. 10 (b), the output end of the EMC module is provided with a first-stage pi-type filter circuit for suppressing the high-frequency common-mode interference signal.
In EMC processing, a primary LC filter circuit and a secondary pi filter circuit are arranged at the input end of an EMC circuit, so that different modes and common mode interference signals in different frequency bands can be attenuated, bus common mode interference and the influence of the different mode interference on a system are filtered, and the stability of the input system is improved. The output end of the EMC circuit is provided with the first-stage pi-type filter circuit, so that high-frequency common-mode interference can be suppressed, and the stability of an output system is improved.
For example, a fuse may be connected at the input of the high voltage bus to ensure that the circuit is effectively broken in the event of a system failure. In order to avoid reverse connection of the high-voltage bus, an input reverse-preventing circuit is adopted, so that safety of the system in reverse connection is ensured. The input enabling of the DC-DC converter is directly set as bus input enabling, and when the DC-DC converter enabling signal is closed or the DC-DC converter is subjected to input overcurrent protection, the system can accurately turn off the output.
As shown in fig. 11, a circuit diagram of the reverse connection preventing and reverse flow preventing circuit is output. And an output reverse connection and anti-backflow protection can be arranged at the output end of the DC-DC converter, so that the damage of an output bus to a system due to the reverse connection is avoided. Meanwhile, on the basis of the output reverse connection protection, the control of the primary output overcurrent protection is additionally added, when the microcontroller 100 detects that the output current is too high or short-circuited, the microcontroller 100 immediately breaks the reverse connection MOS, and cuts off the connection with the output loop, so that the safety of the system is ensured.
In addition, since the output end is connected with the low-voltage battery, in order to prevent the current from flowing into the output anode caused by the fact that the battery voltage is higher than the system output voltage, when the battery voltage is higher than the output voltage, the high potential is output by the pin 2 of U1, the Q19 MOS is disconnected, and the Q19 prevents the current from flowing backwards into the output end of the DC-DC converter, so that the protection function is realized. Meanwhile, the DC-DC converter uses a large amount of vehicle-standard materials, so that the reliability is improved.
As shown in fig. 12, the whole software of the DC-DC converter builds a software architecture according to the design concept of the AUTOSAR, is hierarchical and modularized, weakens the connection between the hardware layer and the upper layer software, unifies the interfaces, and is convenient for the management and maintenance of the whole software system.
The software adopts the definition of various running states, and enters or exits corresponding states under different conditions. Thereby achieving the function of freely switching between states. When the DC-DC converter is powered on, the DC-DC converter is in an initialized state, when the DC-DC converter is not in a charging and discharging state or a dormancy instruction is received in a set time, the DC-DC converter enters the dormancy state, the DC-DC converter initializes the whole configuration after the DC-DC converter is powered on, then set configuration parameters are imported, when the parameters are completely imported, the DC-DC converter enters a self-checking state, and when the self-checking is wrong, the DC-DC converter enters a fault mode and reports faults. When the self-checking is correct, the DC-DC converter enters an operation mode, operates normally and monitors the state of the self-DC converter in real time, and enters a fault mode when the state is detected to exceed a preset parameter threshold value, and performs protection action in the fault mode to report fault information. The DC-DC converter enabling output is controlled by an external controller through a CAN command, and the output voltage and the output current of the DC-DC converter are switched between fixed gears through the CAN command by a remote control device.
Based on the same inventive concept, in this embodiment, a control method of a DC-DC converter is provided, and fig. 13 is a flowchart of a control method of a DC-DC converter provided in an embodiment of the present application, as shown in fig. 13, the method may include:
a signal acquisition module 200, a power module 300, a protection module 400, and a microcontroller 100;
the power module 300 includes a half-bridge driving circuit;
s101, in response to receiving target voltage and/or target current sent by remote control equipment, collecting output voltage and/or output current of a DC-DC converter;
s102, according to the target voltage and/or the target current, the on time and the switching frequency of the MOS tube of the half-bridge driving circuit are adjusted, so that the output voltage of the power supply module is the target voltage and/or the output current of the power supply module is the target current.
The foregoing examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the foregoing examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principles of the present invention should be made therein and are intended to be equivalent substitutes within the scope of the present invention.