Disclosure of Invention
In order to achieve the above object, the present invention provides a temperature control system of a micro inverter, comprising:
at least one path of DC/DC conversion circuit, a temperature detection module and an MCU module;
the temperature detection module is connected with the MCU module and the DC/DC conversion circuit, and the MCU module is connected with the DC/DC conversion circuit;
the DC/DC conversion circuit comprises an LC circuit and a switching device; the DC/DC conversion circuit is pre-provided with a control point temperature and a tripping temperature, wherein the control point temperature is smaller than the tripping temperature;
the temperature detection module detects temperature information of the DC/DC conversion circuit in real time and outputs the temperature information obtained by detection to the MCU module;
the MCU module is used for receiving the temperature information output by the temperature detection module, processing the temperature information into corresponding current detection temperature of the DC/DC conversion circuit, judging the relation between the current detection temperature, the control point temperature and the tripping temperature, outputting a corresponding control signal to the DC/DC conversion circuit, wherein the control signal is used for regulating and controlling the current switching frequency of a switching device in the DC/DC conversion circuit, changing the loss of the LC circuit, enabling the temperature of the DC/DC conversion circuit to oscillate below the tripping temperature, and controlling the temperature of the micro inverter to be stable.
Optionally, the DC/DC conversion circuit includes a full bridge circuit and the LC circuit, and the LC circuit includes an inductor, a second capacitor, and a load; the full-bridge circuit is provided with 4 switching devices, namely a first MOSFET device, a second MOSFET device, a third MOSFET device and a fourth MOSFET device, and the DC/DC conversion circuit specifically comprises: the drain electrode of the first MOSFET device is connected with the positive electrode of the solar cell panel, one end of the first capacitor and the drain electrode of the second MOSFET device, the source electrode of the first MOSFET device is connected with one end of the inductor and the drain electrode of the third MOSFET device, the source electrode of the third MOSFET device is connected with the other end of the first capacitor, the negative electrode of the solar cell panel and the source electrode of the fourth MOSFET device, the source electrode of the second MOSFET device is connected with the drain electrode of the fourth MOSFET device and one end of the second capacitor, the other end of the inductor is connected with one end of the inductor and one end of the load, and the other end of the inductor is connected with the other end of the load and the other end of the second capacitor.
Optionally, the DC/DC conversion circuit further includes a half-bridge circuit and the LC circuit, where the LC circuit includes an inductor, a second capacitor, and a load, the half-bridge circuit includes 2 switching devices, which are a first MOSFET device and a second MOSFET device, and the DC/DC conversion circuit specifically includes: the drain electrode of the first MOSFET device is connected with the positive electrode of the solar cell panel and one end of the first capacitor, the source electrode of the first MOSFET device is connected with one end of the inductor and the drain electrode of the second MOSFET device, the source electrode of the second MOSFET device is connected with the other end of the first capacitor, the negative electrode of the solar cell panel and one end of the second capacitor, the other end of the inductor is connected with one end of the load, and the other end of the second capacitor is connected with the other end of the load.
Optionally, the temperature detection module directly detects temperature information of the DC/DC conversion circuit or detects temperature information of the micro inverter, and when the temperature detection module detects temperature information of the micro inverter, the temperature information of the corresponding DC/DC conversion circuit is obtained after position temperature difference compensation adjustment.
Optionally, the temperature detection module includes an ADC acquisition signal unit and a temperature sensor unit, the temperature sensor unit including: one of a thermistor, thermocouple, platinum resistor and digital temperature sensor.
Optionally, when the temperature sensor unit is the digital temperature sensor, one end of the ADC acquisition signal unit is connected to the digital temperature sensor, the other end of the ADC acquisition signal unit is connected to the MCU module, the ADC acquisition signal unit receives the temperature information of the DC/DC conversion circuit detected by the digital temperature sensor, and the temperature information of the DC/DC conversion circuit is subjected to analog-to-digital conversion and then fed back to the MCU module; when the temperature sensor unit is the thermistor, one end of the ADC acquisition signal unit is connected with the thermistor, the other end of the ADC acquisition signal unit is connected with the MCU module, and the ADC acquisition signal unit acquires the voltage of the thermistor and calculates the temperature information of the DC/DC conversion circuit and feeds back the temperature information of the DC/DC conversion circuit to the MCU module.
Optionally, the step of adjusting and controlling the current switching frequency of the switching device in the DC/DC conversion circuit by the MCU module so that the temperature of the DC/DC conversion circuit is stable includes:
the MCU module judges the current detection temperature of the DC/DC conversion circuitTemperature +.>When the current detection temperature of the DC/DC conversion circuit is +.>Temperature less than the control point of said DC/DC conversion circuit +.>When the switching device in the DC/DC conversion circuit is increasedA current switching frequency; when the current detection temperature of the DC/DC conversion circuit is +.>Temperature of control point greater than the DC/DC conversion circuit>Executing the next step when the current is equal to the current;
judging the tripping temperature of the DC/DC conversion circuitAnd the current detection temperature of the DC/DC conversion circuit +.>And a preset trip temperature of said DC/DC conversion circuit>And the current detection temperature of the DC/DC conversion circuit +.>Threshold value of difference->When the trip temperature of the DC/DC conversion circuit is +.>And the current detection temperature of the DC/DC conversion circuit +.>The difference value of (2) is smaller than the preset trip temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>Threshold value of difference->I.e. +.><When the current switching frequency of a switching device in the DC/DC conversion circuit is reduced; when the tripping temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>The difference value of (2) is larger than the preset trip temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>Threshold value of difference->I.e. +.>＞Executing the next step when the current is equal to the current;
judging the DC/DC conversion circuitA size relationship with 0, wherein,
when (when)When < 0, judging +.>In the size relation of (1)Increasing the current switching frequency of the switching device in the DC/DC conversion circuit by a second amplitude per unit time; if->Increasing the current switching frequency of the switching device in the DC/DC conversion circuit by a first amplitude per unit time, wherein +.>For the change of the currently detected temperature>For the time interval of the temperature detection,the change of the temperature is detected last time;
when (when)Judging +.>And->The magnitude relation of (1) if->＞The current switching frequency of the switching devices in the DC/DC conversion circuit is reduced by a first amplitude per unit time if +.>＜Then the current switching frequency of the switching device in the DC/DC conversion circuit is reduced by a second amplitude in unit time, whereinThe amplitude is a percentage of a current switching frequency of the switching device, the first amplitude being greater than the second amplitude.
Optionally, the temperature detection module and the DC/DC conversion circuit are integrated on the same printed circuit board.
The embodiment of the invention also provides a temperature control method of the micro inverter, which comprises the following steps:
the temperature detection module detects temperature information of the DC/DC conversion circuit in real time and outputs the temperature information obtained by detection to the MCU module;
the MCU module is used for receiving the temperature information output by the temperature detection module, processing the temperature information into corresponding current detection temperature of the DC/DC conversion circuit, judging the relation between the current detection temperature and preset control point temperature and trip temperature of the DC/DC conversion circuit, and outputting corresponding control signals to the DC/DC conversion circuit, wherein the control signals are used for regulating and controlling the current switching frequency of a switching device in the DC/DC conversion circuit, changing the loss of an LC circuit in the DC/DC conversion circuit, enabling the temperature of the DC/DC conversion circuit to oscillate below the trip temperature, and controlling the temperature of the micro inverter to be stable.
Optionally, the step of controlling the temperature of the micro inverter by the MCU module controlling the current switching frequency of the switching device in the DC/DC conversion circuit includes:
the MCU module judges the current detection temperature of the DC/DC conversion circuitTemperature +.>When the current detection temperature of the DC/DC conversion circuit is +.>Temperature less than the control point of said DC/DC conversion circuit +.>Increasing a current switching frequency of a switching device in the DC/DC conversion circuit; when the current detection temperature of the DC/DC conversion circuit is +.>Temperature of control point greater than the DC/DC conversion circuit>Executing the next step when the current is equal to the current;
judging the tripping temperature of the DC/DC conversion circuitAnd the current detection temperature of the DC/DC conversion circuit +.>And a preset trip temperature of said DC/DC conversion circuit>And the current detection temperature of the DC/DC conversion circuit +.>Threshold value of difference->When the trip temperature of the DC/DC conversion circuit is +.>And the current detection temperature of the DC/DC conversion circuit +.>The difference value of (2) is smaller than the preset trip temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>Difference valueThreshold of->I.e. +.><When the current switching frequency of a switching device in the DC/DC conversion circuit is reduced; when the tripping temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>The difference value of (2) is larger than the preset trip temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>Threshold value of difference->I.e. +.>＞Executing the next step when the current is equal to the current;
judging the DC/DC conversion circuitA size relationship with 0, wherein,
when (when)When < 0, judging +.>In the size relation of (1)Increasing the current switching frequency of the switching device in the DC/DC conversion circuit by a second amplitude per unit time; if->Increasing the current switching frequency of the switching device in the DC/DC conversion circuit by a first amplitude per unit time, wherein +.>For the change of the currently detected temperature>For the time interval of the temperature detection,the change of the temperature is detected last time;
when (when)Judging +.>And->The magnitude relation of (1) if->＞The current switching frequency of the switching devices in the DC/DC conversion circuit is reduced by a first amplitude per unit time if +.>＜The current switching frequency of the switching devices in the DC/DC conversion circuit is reduced by a second amplitude per unit time, wherein the amplitude is a percentage of the current switching frequency of the switching devices, and the first amplitude is greater than the second amplitude.
In summary, the invention has the advantages that:
the invention provides a temperature control system and a temperature control method of a micro inverter. The temperature of the DC/DC conversion circuit is detected by the temperature detection module to obtain temperature information, the temperature information is compared with a preset control point temperature and a tripping temperature to judge, a corresponding control signal is output to the DC/DC conversion circuit, the control signal is used for regulating and controlling the current switching frequency of a switching device in the DC/DC conversion circuit, so that the loss of an LC circuit in the DC/DC conversion circuit is changed, the working temperature of the DC/DC conversion circuit is controlled to oscillate below the tripping temperature, on one hand, the output power loss caused by the fact that the micro inverter is not working due to tripping of the DC/DC conversion circuit caused by overhigh temperature is reduced, and on the other hand, the micro inverter always works in a state close to the highest efficiency, and the safety and the normal operation of the micro inverter circuit and micro inverter equipment are ensured.
Detailed Description
The present invention will be described in further detail with reference to specific examples for the purpose of facilitating understanding to those skilled in the art.
The invention provides a temperature control system of a micro inverter, as shown in fig. 1, comprising:
at least one path of DC/DC conversion circuit 10, temperature detection module 30, MCU module 40;
the temperature detection module 30 is connected with the MCU module 40 and the DC/DC conversion circuit 10, and the MCU module 40 is connected with the DC/DC conversion circuit 10;
the DC/DC conversion circuit 10 includes an LC circuit and a switching device; the DC/DC conversion circuit 10 is preset with a control point temperature and a trip temperature, wherein the control point temperature is less than the trip temperature;
the temperature detection module 30 detects temperature information of the DC/DC conversion circuit 10 in real time, and outputs the detected temperature information to the MCU module 40;
the MCU module 40 is configured to receive the temperature information output by the temperature detection module 30, process the temperature information into a corresponding current detected temperature of the DC/DC conversion circuit 10, and determine that, based on a relationship between the current detected temperature, the control point temperature, and the trip temperature, a corresponding control signal is output to the DC/DC conversion circuit 10, where the control signal is used to regulate a current switching frequency of a MOSFET device in the DC/DC conversion circuit 10, and change a loss of the LC circuit, so that the temperature of the DC/DC conversion circuit 10 oscillates below the trip temperature, thereby controlling temperature stability of the micro inverter.
Specifically, in the embodiment of the present invention, as shown in fig. 2, the micro inverter further includes a DC/AC inverter circuit 20, one end of the DC/AC inverter circuit 20 is connected to the DC/DC conversion circuit 10, and the output power of the DC/DC conversion circuit 10 is used as the input power of the DC/AC inverter circuit 20.
In the embodiment of the present invention, as shown in fig. 3, the DC/DC conversion circuit 10 includes a full-bridge circuit and the LC circuit, the full-bridge circuit is connected to the LC circuit, the LC circuit includes an inductance Lr, a second capacitance Cr, and a load Z0, the full-bridge circuit includes 4 switching devices, which are a first MOSFET device Q1, a second MOSFET device Q2, a third MOSFET device Q3, and a fourth MOSFET device Q4, and the DC/DC conversion circuit 10 specifically includes: the drain electrode of the first MOSFET device Q1 is connected with the positive electrode of the solar panel, one end of the first capacitor C1 and the drain electrode of the second MOSFET device Q2, the source electrode of the first MOSFET device Q1 is connected with one end of the inductor Lr and the drain electrode of the third MOSFET device Q3, the source electrode of the third MOSFET device Q3 is connected with the other end of the first capacitor C1, the negative electrode of the solar panel and the source electrode of the fourth MOSFET device Q4, the source electrode of the second MOSFET device Q2 is connected with the drain electrode of the fourth MOSFET device Q4 and one end of the second capacitor Cr, the other end of the inductor Lr is connected with one end of the inductor Lm and one end of the load Z0, and the other end of the inductor Lm is connected with the other end of the load Z0 and the other end of the second capacitor Cr; wherein the load Z0 includes: a resistive load, a capacitive load, an inductive load, or a transformer.
Inductance X due to said inductance LrL =ωl=2pi fLr, where ω is the angular velocity, X, of the current through the inductance LrL An inductance of the inductance Lr, f being the current switching frequency of the MOSFET device, the inductance of the inductance LrAnd the current switching frequency of said MOSFET device +.>Proportional to the ratio; capacitive reactance X of the second capacitor CrC =1/(ωcr) =1/(2π fCr), where XC For the capacitive reactance of the second capacitor Cr, the capacitive reactance XC Inversely proportional to the current switching frequency f of the MOSFET device. Namely: when the current switching frequency f of the MOSFET device increases, the inductance X of the inductorL Increase the capacitance of the capacitoranti-XC A reduction; when the current switching frequency f of the MOSFET device decreases, the inductance X of the inductance LrL Reducing the capacitive reactance X of the second capacitor CrC An increase; when the current switching frequency f of the MOSFET device is equal to the resonant frequency of the LC circuit, the impedance presented by the DC/DC conversion circuit 10 is the largest, and the temperature of the DC/DC conversion circuit 10 is the highest;
when the current switching frequency f of the first MOSFET device Q1, the fourth MOSFET device Q4 or the second MOSFET device Q2, the third MOSFET device Q3 in the DC/DC conversion circuit 10 changes, the inductance X of the inductance Lr in the DC/DC conversion circuit 10L Capacitive reactance X of said second capacitance CrC And will also change accordingly, the impedance presented by the DC/DC conversion circuit 10 will change, so as to regulate the temperature of the DC/DC conversion circuit 10, namely: when the first MOSFET device Q1 and the fourth MOSFET device Q4 are adjusted to be on, the second MOSFET device Q2 and the third MOSFET device Q3 are turned off, and the current switching frequency f of the first MOSFET device Q1 and the fourth MOSFET device Q4 is smaller than the resonant frequency of the LC circuit, the impedance presented by the DC/DC conversion circuit 10 becomes smaller, the loss of the DC/DC conversion circuit 10 decreases, and the temperature of the DC/DC conversion circuit 10 decreases; conversely, when the first MOSFET device Q1 and the fourth MOSFET device Q4 are adjusted to be turned on, the second MOSFET device Q2 and the third MOSFET device Q3 are turned off, and the current switching frequency f of the first MOSFET device Q1 and the fourth MOSFET device Q4 approaches the corresponding resonant frequency of the LC circuit, the impedance presented by the DC/DC conversion circuit 10 increases, the loss of the DC/AC conversion circuit increases, and the temperature of the DC/DC conversion circuit 10 increases; or when the first MOSFET device Q1 and the fourth MOSFET device Q4 are adjusted to be turned off, the second MOSFET device Q2 and the third MOSFET device Q3 are turned on, and the current switching frequency f of the first MOSFET device Q1, the second MOSFET device Q2 and the third MOSFET device Q3 is smaller than the resonant frequency of the LC circuit, the impedance presented by the DC/DC conversion circuit 10 becomes smaller, the loss of the DC/DC conversion circuit 10 decreases, and the temperature of the DC/DC conversion circuit 10 decreases; conversely, when the first position is adjustedAnd when the current switching frequency f of the second MOSFET device Q2 and the third MOSFET device Q3 approaches the corresponding resonant frequency of the LC circuit, the impedance presented by the DC/DC conversion circuit 10 becomes larger, the loss of the DC/AC conversion circuit increases, and the temperature of the DC/DC conversion circuit 10 increases.
In other embodiments, as shown in fig. 4, the DC/DC conversion circuit further includes a half-bridge circuit and the LC circuit, where the half-bridge circuit is connected to the LC circuit, the LC circuit includes an inductance Lr, a second capacitance Cr, and a load Z0, the half-bridge circuit has 2 switching devices, which are a first MOSFET device Q1 and a second MOSFET device Q2, and the DC/DC conversion circuit specifically includes: the drain electrode of the first MOSFET device Q1 is connected with the positive electrode of the solar panel and one end of the first capacitor C1, the source electrode of the first MOSFET device Q1 is connected with one end of the inductor Lr and the drain electrode of the second MOSFET device Q2, the source electrode of the second MOSFET device Q2 is connected with the other end of the first capacitor C1, the negative electrode of the solar panel and one end of the second capacitor Cr, the other end of the inductor Lr is connected with one end of the load Z0, and the other end of the second capacitor Cr is connected with the other end of the load Z0; wherein the load Z0 includes: a resistive load, a capacitive load, an inductive load, or a transformer.
In an embodiment of the present invention, the current switching frequency of the MOSFET devices in the DC/DC conversion circuit 10 is adjusted using a PFM (pulse current switching frequency modulation) module.
In the embodiment of the invention, the temperature detection module directly detects the temperature information of the DC/DC conversion circuit or detects the temperature information of the micro inverter, and when the temperature detection module detects the temperature information of the micro inverter, the temperature information of the corresponding DC/DC conversion circuit is obtained after position temperature difference compensation adjustment.
In an embodiment of the present invention, the temperature detection module includes an ADC acquisition signal unit and a temperature sensor unit, where the temperature sensor unit includes: one of a thermistor, thermocouple, platinum resistor and digital temperature sensor.
In the embodiment of the present invention, when the temperature sensor unit is the digital temperature sensor, one end of the ADC collecting signal unit is connected to the digital temperature sensor, the other end of the ADC collecting signal unit is connected to the MCU module 40, and the ADC collecting signal unit receives the temperature information of the DC/DC conversion circuit 10 detected by the digital temperature sensor, and performs analog-to-digital conversion on the temperature information of the DC/DC conversion circuit 10 and feeds back the temperature information to the MCU module 40.
In other embodiments, when the temperature sensor unit is the thermistor, one end of the ADC collecting signal unit is connected to the thermistor, the other end of the ADC collecting signal unit is connected to the MCU module, and the ADC collecting signal unit collects the voltage of the thermistor and calculates the temperature information of the DC/DC conversion circuit, and feeds back the temperature information of the DC/DC conversion circuit to the MCU module.
In an embodiment of the present invention, as shown in fig. 5, the step of adjusting the current switching frequency of the switching device in the DC/DC conversion circuit 10 by the MCU module 40 so that the temperature of the DC/DC conversion circuit 10 is stable includes:
the MCU module 40 judges the current detected temperature of the DC/DC conversion circuit 10Temperature +/with control point of the DC/DC conversion circuit 10>When the current detection temperature of the DC/DC conversion circuit 10 is +.>Less than the control point temperature of the DC/DC conversion circuit 10 +.>Increasing the current switching frequency of the switching device; when the current detection of the DC/DC conversion circuit 10Temperature->Is greater than the control point temperature of the DC/DC converter circuit 10>When that is the case, the next step is performed.
The current detected temperature of the DC/DC conversion circuit 10Less than the control point temperature +.>In this case, by increasing the current switching frequency of the switching device, the DC/DC conversion circuit 10 operates at a better oscillating frequency, so that the LC circuit impedance in the DC/DC conversion circuit 10 is optimized, and the output power of the DC/DC conversion circuit 10 is improved, thereby improving the working efficiency of the micro inverter.
Determining a trip temperature of the DC/DC conversion circuit 10And the current detected temperature of said DC/DC conversion circuit 10 +.>And a preset trip temperature of said DC/DC conversion circuit 10 +.>And the current detected temperature of said DC/DC conversion circuit 10 +.>Threshold value of difference->When the trip temperature of the DC/DC conversion circuit 10 is +.>With the current detected temperature of the DC/DC conversion circuit 10Is smaller than a predetermined trip temperature of the DC/DC conversion circuit 10 +.>And the current detected temperature of said DC/DC conversion circuit 10 +.>Threshold value of difference->I.e. +.><When the current switching frequency of the switching device is reduced; when the trip temperature of the DC/DC conversion circuit 10 +.>And the current detected temperature of said DC/DC conversion circuit 10 +.>Is greater than a predetermined trip temperature of the DC/DC conversion circuit 10>And the current detected temperature of said DC/DC conversion circuit 10 +.>Threshold value of difference->I.e. +.>＞When that is the case, the next step is performed.
Presetting the trip temperature of the DC/DC conversion circuit 10And the current detected temperature of said DC/DC conversion circuit 10 +.>Threshold value of difference->By judging->And->Before the DC/DC conversion circuit 10 trips, the DC/DC conversion circuit 10 is subjected to temperature detection and then to subsequent temperature regulation, so that the DC/DC conversion circuit 10 is always at a trip temperature +.>The following oscillations.
Judging the DC/DC conversion circuit 10A size relationship with 0, wherein,
when (when)When < 0, judging +.>In the size relation of (1)Increasing the current switching frequency of the switching device by a second magnitude per unit time; if it isThen the current switching frequency of the switching device is increased by a first amplitude in unit timeIn (I)>For the change of the currently detected temperature>For the time interval of the temperature detection, +.>The change of the temperature is detected last time;
when (when)In this case, the +.A. of the DC/DC conversion circuit 10 is judged>And->The magnitude relation of (1) if->＞The current switching frequency of the switching device is reduced by a first amplitude per unit time, if +.>＜The current switching frequency of the switching device is reduced by a second amplitude per unit time, wherein the amplitude is a percentage of the current switching frequency of the switching device, and the first amplitude is greater than the second amplitude.
JudgingAnd 0, thereby judging the temperature variation trend of the DC/DC conversion circuit 10,
if it is> 0, the temperature change trend of the DC/DC conversion circuit 10 is a temperature rise, and the temperature rise is further improved by comparison +.>And->The magnitude relation of the DC/DC conversion circuit 10 is determined as an acceleration temperature rise or a deceleration temperature rise;
if it is< 0, the temperature change trend of the DC/DC conversion circuit 10 is temperature reduction, further by comparisonAnd->The magnitude relation of the voltage of the DC/DC conversion circuit 10 is judged to be the accelerated cooling or the decelerated cooling, so that the current switching frequency of the switching device is regulated and controlled according to different conditions, the loss of the LC circuit is changed, the working temperature of the DC/DC conversion circuit 10 oscillates below the approximate trip temperature, on one hand, the output power loss caused by the fact that the micro inverter is not operated due to the fact that the DC/DC conversion circuit 10 trips due to overhigh temperature is reduced, on the other hand, the micro inverter always works in the approximate highest efficiency state, and meanwhile, the damage of the DC/DC conversion circuit 10 caused by overhigh temperature of the DC/DC conversion circuit 10 is avoided, and the safety and the normal operation of the micro inverter circuit and micro inverter equipment are ensured.
In the embodiment of the invention, the value of the first amplitude decrease and increase in the unit time is 3% of the current switching frequency of the switching device at the previous moment, and the value of the second amplitude decrease and increase in the unit time is 1% of the current switching frequency of the switching device at the previous moment, or the specific value change is set according to specific situations.
As shown in fig. 6, the present invention adjusts the current switching frequency of the switching device in the DC/DC conversion circuit 10, so as to change the loss of the LC circuit, so that the temperature of the DC/DC conversion circuit 10 approaches the trip temperature, and oscillates below the trip temperature of the DC/DC conversion circuit 10, thereby avoiding the overhigh temperature of the DC/DC conversion circuit 10, ensuring the safe and normal operation of the DC/DC conversion circuit 10 and the micro inverter device, and improving the working efficiency of the micro inverter.
The temperature control system of the micro inverter provided by the invention has a simple structure, and is beneficial to miniaturization of the micro inverter.
In the embodiment of the present invention, the temperature detection module 30 and the DC/DC conversion circuit are integrated on the same printed circuit board.
The embodiment of the invention also provides a temperature control system and a temperature control method of the micro inverter, wherein the temperature control system comprises the following steps:
the temperature detection module detects temperature information of the DC/DC conversion circuit in real time and outputs the temperature information obtained by detection to the MCU module;
the MCU module is used for receiving the temperature information output by the temperature detection module, processing the temperature information into corresponding current detection temperature of the DC/DC conversion circuit, judging the relation between the current detection temperature and preset control point temperature and trip temperature of the DC/DC conversion circuit, and outputting corresponding control signals to the DC/DC conversion circuit, wherein the control signals are used for regulating and controlling the current switching frequency of a switching device in the DC/DC conversion circuit, changing the loss of an LC circuit in the DC/DC conversion circuit, enabling the temperature of the DC/DC conversion circuit to oscillate below the trip temperature, and controlling the temperature of the micro inverter to be stable.
In the embodiment of the invention, the step of controlling the temperature of the micro inverter by the MCU module for regulating the current switching frequency of the switching device in the DC/DC conversion circuit comprises the following steps:
the MCU module judges the current detection temperature of the DC/DC conversion circuitTemperature +.>When the current detection temperature of the DC/DC conversion circuit is +.>Temperature less than the control point of said DC/DC conversion circuit +.>Increasing a current switching frequency of a switching device in the DC/DC conversion circuit; when the current detection temperature of the DC/DC conversion circuit is +.>Temperature of control point greater than the DC/DC conversion circuit>Executing the next step when the current is equal to the current;
judging the tripping temperature of the DC/DC conversion circuitAnd the current detection temperature of the DC/DC conversion circuit +.>And a preset trip temperature of said DC/DC conversion circuit>And the current detection temperature of the DC/DC conversion circuit +.>Threshold value of difference->When the trip temperature of the DC/DC conversion circuit is +.>And the current detection temperature of the DC/DC conversion circuit +.>The difference value of (2) is smaller than the preset trip temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>Threshold value of difference->I.e. +.><When the current switching frequency of a switching device in the DC/DC conversion circuit is reduced; when the tripping temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>The difference value of (2) is larger than the preset trip temperature of the DC/DC conversion circuit +.>And the current detection temperature of the DC/DC conversion circuit +.>Threshold value of difference->I.e. +.>＞Executing the next step when the current is equal to the current;
judging the DC/DC conversion circuitA size relationship with 0, wherein,
when (when)When < 0, judging +.>In the size relation of (1)Increasing the current switching frequency of the switching device in the DC/DC conversion circuit by a second amplitude per unit time; if->Increasing the current switching frequency of the switching device in the DC/DC conversion circuit by a first amplitude per unit time, wherein +.>For the change of the currently detected temperature>For the time interval of the temperature detection,the change of the temperature is detected last time;
when (when)Judging +.>And->The magnitude relation of (1) if->＞The current switching frequency of the switching devices in the DC/DC conversion circuit is reduced by a first amplitude per unit time if +.>＜The current switching frequency of the switching devices in the DC/DC conversion circuit is reduced by a second amplitude per unit time, wherein the amplitude is a percentage of the current switching frequency of the switching devices, and the first amplitude is greater than the second amplitude.
In the embodiment of the invention, the value of the first amplitude decrease and increase in the unit time is 3% of the current switching frequency of the switching device at the previous moment, and the value of the second amplitude decrease and increase in the unit time is 1% of the current switching frequency of the switching device at the previous moment, or the specific value change is set according to specific situations.
Finally, any modification or equivalent replacement of some or all of the technical features by means of the structure of the device according to the invention and the technical solutions of the examples described, the resulting nature of which does not deviate from the corresponding technical solutions of the invention, falls within the scope of the structure of the device according to the invention and the patent claims of the embodiments described.