Driving circuit and method for prolonging expected life of energy storage inverter

Abstract

The invention discloses a driving circuit and method for prolonging the expected life of an energy storage inverter. The driving circuit comprises a driving control module, a first resistance network, a second resistance network and a power switch device, the driving control module comprises a PWM signal input end, a gating signal input end, a first driving output end and a second driving output end; the PWM signal input end provides a driving signal waveform, the gating signal input end is used for gating the first driving output end or the second driving output end to output a driving signal, and the first driving output end is connected with a control end of the power switch device through a first resistance network; and the second driving output end is connected with the control end of the power switch device through the second resistance network. According to the invention, a controllable double-path driving circuit is provided for power switching devices such as an MOSFET, an IGBT and the like, so that derating processing can be flexibly carried out on the output power of the power switching devices during working, and the expected life of the energy storage inverter is effectively prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of inverters, and in particular to a driving circuit and method for improving the expected life of an energy storage inverter. Background Art

[0002] The high-power three-level IGBT and other power switching devices used in mainstream energy storage inverters have high heat dissipation requirements and require independent air ducts and outdoor high-protection grade fans for heat dissipation. For higher-power energy storage inverters, water cooling is required, while for low-power household energy storage inverters, a self-cooling solution with a built-in fan is used.

[0003] After statistical analysis, most of the failures of power switching devices and key components are caused by temperature. Therefore, the heat dissipation design of energy storage inverters is extremely important. At present, thermal simulation is first performed and then verified by actual measurement. For temperature, over-temperature protection is implemented at a certain threshold, and shutdown protection is performed when the threshold is exceeded. In order to prevent high-temperature failure of devices, either more margin design solutions are adopted; or temperature protection is strictly controlled, which lacks flexible design.

[0004] The power switching devices of the energy storage inverter have charging, discharging, active, reactive and 1.1 times load requirements. In addition, with the development trend of increasingly higher DC working voltage, how to ensure the expected service life of the energy storage inverter, especially the power switching devices, is a major technical challenge. Summary of the invention

[0005] The present invention aims to provide a driving circuit and method for improving the expected life of an energy storage inverter, and its purpose is to solve the problem from the root and realize that the power consumption of the power switching device can be adjusted. The technical solution is as follows:

[0006] A driving circuit for improving the expected life of an energy storage inverter, comprising a driving control module, a first resistor network, a second resistor network and a power switch device;

[0007] The drive control module includes a PWM signal input terminal, a selection signal input terminal, a first drive output terminal, and a second drive output terminal; the PWM signal input terminal provides a drive signal waveform, the selection signal input terminal is used to select the first drive output terminal or the second drive output terminal to output a drive signal, the first drive output terminal is connected to the control terminal of the power switch device through the first resistor network, and the second drive output terminal is connected to the control terminal of the power switch device through the second resistor network.

[0008] Further, the drive control module includes a logic control unit, a first drive unit and a second drive unit;

[0009] The logic control unit includes executing the following control logic:

[0010] Performing a logic AND calculation on the PWM signal and the strobe signal, and then outputting a first high-side drive signal;

[0011] Performing a logical AND calculation on the PWM signal after the logical NOT calculation and the selection signal, and then outputting a first low-side drive signal;

[0012] Performing a logical AND calculation on the PWM signal and the selection signal after logical NOT calculation, and then outputting a second high-side drive signal;

[0013] Performing a logic AND calculation on the PWM signal after the logical NOT calculation and the selection signal after the logical NOT calculation, and then outputting a second low-side drive signal;

[0014] The first driving unit includes a dual-channel signal driving circuit and a first half-bridge driving circuit. The first high-side driving signal and the first low-side driving signal are respectively connected to the high-side control end and the low-side control end of the first half-bridge driving circuit after being driven by the signal driving circuit. The output of the first half-bridge driving circuit is the output of the first driving unit; the second driving unit includes a dual-channel signal driving circuit and a second half-bridge driving circuit. The second high-side driving signal and the second low-side driving signal are respectively connected to the high-side control end and the low-side control end of the second half-bridge driving circuit through the signal driving circuit. The output of the second half-bridge driving circuit is the output of the second driving unit.

[0015] Furthermore, the signal driving circuit is a MOS driving chip.

[0016] Furthermore, the signal driving circuit is an optocoupler.

[0017] Furthermore, when there are N power switch devices, N drive control modules are used for driving, each drive control module is driven by one PWM signal, and is uniformly gate-controlled by one gate signal.

[0018] Furthermore, the resistor network is a combination of a resistor and a diode, including a first loop and a second loop connected in parallel; the first loop only includes a resistor, and the second loop includes a resistor and a diode connected in series.

[0019] The present invention also provides a method for improving the expected life of an energy storage inverter, which is applied to the driving circuit for improving the expected life of the energy storage inverter as described above, and comprises the following steps:

[0020] The driving circuit of the power switch device adopts the driving circuit as described above to improve the expected life of the energy storage inverter;

[0021] Setting a power degradation parameter and a threshold value of the power switch device; the degradation parameter includes at least one of an operating voltage, an output power and a junction temperature of the power switch device of the energy storage inverter;

[0022] Periodically detecting power degradation parameters of power switching devices;

[0023] When the power reduction parameter is greater than a set threshold, power reduction is performed by selecting a driving resistor with a larger resistance value through a selection signal or by reducing the frequency of a PWM signal.

[0024] Furthermore, when the power degradation parameter is the DC side voltage of the energy storage inverter, the power degradation is performed by adopting a gating signal to select a driving resistor with a larger resistance value.

[0025] Furthermore, when the power degradation parameter is the output power of the energy storage inverter, the power degradation is performed by reducing the frequency of the PWM signal.

[0026] Furthermore, when the power degradation parameter is the junction temperature of the power switch device, the power degradation is performed by comprehensively selecting a driving resistor with a larger resistance through a selection signal and reducing the frequency of a PWM signal until shutdown protection is performed.

[0027] The present invention achieves the following technical effects:

[0028] The present invention provides a controllable dual-path drive circuit for power switch devices such as MOSFET and IGBT, so that the output power of the power switch device can be flexibly derated during operation, thereby effectively improving the expected life of the energy storage inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a functional diagram of a driving circuit of a single power switch device of the present invention;

[0030] Figure 2 is a circuit diagram of an embodiment of a drive control module of the present invention;

[0031] Figure 3 is a circuit diagram of an embodiment of a drive control module of the present invention;

[0032] Figure 4 is a circuit diagram of an embodiment of a drive control module of the present invention;

[0033] Figure 5 is a circuit diagram of a dual drive circuit of the present invention;

[0034] Figure 6 It is a schematic diagram of a driving circuit of an energy storage inverter of the present invention;

[0035] Figure 7This is a modified example of the driving resistor network of the driving circuit of the present invention. DETAILED DESCRIPTION

[0036] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0037] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0038] like Figure 1 As shown, the present invention provides a driving circuit for improving the expected life of an energy storage inverter, including a driving control module, a first resistor network, a second resistor network and a power switch device (such as IGBT).

[0039] The drive control module includes a PWM signal input terminal, a gate signal input terminal, a first drive output terminal and a second drive output terminal. The PWM signal input terminal provides a drive signal waveform, the gate signal input terminal I / O provides a control signal for switching the drive resistance loop, and resistors R1 and R2 represent the first resistance network and the second resistance network, respectively, and are connected to the first drive output terminal and the second drive output terminal of the drive control module, respectively. Preferably, resistors R1 and R2 can include various drive forms such as a resistor combination and a resistor plus a diode combination, so as to realize different drive realizations of power switching devices Q1 such as IGBTs.

[0040] The parameters that affect the expected life of the energy storage inverter mainly include the operating voltage of the energy storage inverter (such as the DC side voltage), the output power and the junction temperature of the power switch device, etc. Therefore, when the energy storage inverter is working, it is necessary to periodically collect the parameters such as the operating voltage and the junction temperature of the power switch device that affect the expected life of the inverter.

[0041] The working logic of the drive circuit is:

[0042] (1) Monitor the working voltage of the energy storage inverter; when the working voltage is U1 (with hysteresis) or below, set the selection signal high, select the first drive output terminal to drive Q1 through the drive resistor R1; when the working voltage is above U2 (with hysteresis), set the selection signal low, select the second drive output terminal to drive Q1 through the drive resistor R2, thereby achieving a design that can meet the requirements of the safe working area and achieve lower power consumption under certain working conditions.

[0043] (2) Monitor the output power of the energy storage inverter; when the output power is P1 (with hysteresis) or below, the switching frequency of the PWM signal adopts a higher frequency f1; when the output power is above P2 (with hysteresis), the switching frequency of the PWM signal adopts a lower frequency f2.

[0044] (3) Monitor the temperature of the NTC inside the IGBT, and select the power value or current value according to the temperature of the NTC inside the IGBT. When the temperature of the NTC inside the IGBT is T1 (with a hysteresis loop) or below, the switching frequency of the PWM signal adopts a higher frequency f1, so that Q1 works at a predetermined power or current; when the temperature is between T1 and T2, the switching frequency of the PWM signal adopts a lower frequency f2, so that the power or current of Q1 works in a linearly derated manner; when the temperature reaches T2, the output of the PWM signal is turned off, thereby simultaneously turning off the output of the first drive output terminal and the second drive output terminal, so that the power or current of Q1 drops to 0 and stops working.

[0045] like Figures 2 to 4 As shown, on the driving side of power switching devices such as IGBT, the PWM signal and the selection signal pass through a series of logic processing circuits to realize the scheme of switching the power switching devices (such as IGBT, etc.) at the back end through the driving resistor R1 and the driving resistor R2. The working principle is:

[0046] When the selection signal CTRL1 is at a high level, the circuit driving the resistor R1 works normally, while the circuit driving the resistor R2 does not work; on the contrary, when the selection signal CTRL1 is at a low level, the circuit driving the resistor R1 does not work, while the circuit driving the resistor R2 works normally. The above circuit characteristics well implement the technical objectives of the present invention.

[0047] Figure 2 A circuit example of a drive control module is given. The circuit of the drive control module consists of a logic control unit (composed of logic gate circuits U1 to U8), drive chips U9 and U10, and two sets of half-bridge circuits. The drive chips U9 and U10 in the circuit are dual-channel MOS drive chips, which can increase the drive capability and realize bootstrap drive. For example, the HO pin and LO pin of the drive chip U9 output high-side drive signals and low-side drive signals to drive the upper bridge arm MOS tube and the lower bridge arm MOS tube of the half-bridge circuit in a time-sharing manner.

[0048] Figure 3 As another circuit example of the driving control module, a different dual-channel MOS driving chip is used.

[0049] Figure 4 As another circuit example of the drive control module, four optocouplers are used to implement the front-end drive logic to operate in the back-end circuit.

[0050] There are many other implementation modes of the circuit of the drive control module, which will not be further elaborated here.

[0051] like Figure 5 and Figure 6 As shown, when multiple driving circuits are controlled simultaneously, each driving control module is driven by one PWM signal (PWM1, PWM2, etc.) and is uniformly gated and controlled by one gate signal CTRL1.

[0052] like Figure 7 As shown, the driving resistor network of the driving circuit can also be deformed, such as Figure 7 As shown. In this embodiment, the two driving resistor networks are composed of resistors R1ON, R1OFF and diode D1, and resistors R2ON, R2OFF and diode D2. In this way, the driving resistor network has different resistance values ​​in high-side driving and low-side driving, forming a combination of different on and off speeds, which can achieve technical effects such as more reasonable use of power devices.

[0053] Based on the above driving circuit, the present invention also provides a method for improving the expected life of the energy storage inverter, comprising the following steps:

[0054] The power degradation parameters and thresholds of the power switch device are set; the power degradation parameters include the operating voltage, output power and junction temperature of the energy storage inverter, and one or more parameters can be selected for power control.

[0055] When the energy storage inverter is working, the power degradation parameters of the power switching device are periodically detected;

[0056] When the power reduction parameter is greater than a set threshold, power reduction can be performed by selecting a driving resistor with a larger resistance value through a selection signal or by reducing the frequency of a PWM signal.

[0057] Specifically, when the power derating parameter is the DC side voltage of the energy storage inverter, the power derating is performed by selecting a driving resistor with a larger resistance value through a selection signal; when the power derating parameter is the output power of the energy storage inverter, the power derating can be performed by reducing the frequency of a PWM signal; when the power derating parameter is the junction temperature of the power switching device, the above two methods can be used in combination to perform power derating. When the junction temperature is less than T1, the system operates normally. When the junction temperature is between T1 and T2, the power is linearly degraded. When the junction temperature of the power switching device reaches T2, the system is shut down for protection.

[0058] In summary, the present invention provides a controllable dual-path drive circuit for power switching devices such as MOSFET and IGBT, so that the output power of the power switching devices can be flexibly derated during operation, thereby effectively improving the expected life of the energy storage inverter.

[0059] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A driving circuit for improving the expected life of an energy storage inverter, characterized in that: It includes a drive control module, a first resistor network, a second resistor network and a power switch device; The drive control module includes a PWM signal input terminal, a selection signal input terminal, a first drive output terminal, and a second drive output terminal; the PWM signal input terminal provides a drive signal waveform, the selection signal input terminal is used to select the first drive output terminal or the second drive output terminal to output a drive signal, the first drive output terminal is connected to the control terminal of the power switch device through the first resistor network, and the second drive output terminal is connected to the control terminal of the power switch device through the second resistor network.

2. The drive circuit for improving the expected life of the energy storage inverter according to claim 1, characterized in that: The drive control module includes a logic control unit, a first drive unit and a second drive unit; The logic control unit includes executing the following control logic: Performing a logic AND calculation on the PWM signal and the strobe signal, and then outputting a first high-side drive signal; Performing a logical AND calculation on the PWM signal after the logical NOT calculation and the selection signal, and then outputting a first low-side drive signal; Performing a logical AND calculation on the PWM signal and the selection signal after logical NOT calculation, and then outputting a second high-side drive signal; Performing a logic AND calculation on the PWM signal after the logical NOT calculation and the selection signal after the logical NOT calculation, and then outputting a second low-side drive signal; The first driving unit includes a dual-channel signal driving circuit and a first half-bridge driving circuit. The first high-side driving signal and the first low-side driving signal are respectively connected to the high-side control end and the low-side control end of the first half-bridge driving circuit after being driven by the signal driving circuit. The output of the first half-bridge driving circuit is the output of the first driving unit; the second driving unit includes a dual-channel signal driving circuit and a second half-bridge driving circuit. The second high-side driving signal and the second low-side driving signal are respectively connected to the high-side control end and the low-side control end of the second half-bridge driving circuit through the signal driving circuit. The output of the second half-bridge driving circuit is the output of the second driving unit.

3. The drive circuit for improving the expected life of the energy storage inverter according to claim 2, characterized in that: The signal driving circuit is a MOS driving chip.

4. The drive circuit for improving the expected life of the energy storage inverter according to claim 2, characterized in that: The signal driving circuit is an optocoupler.

5. The driving circuit for improving the expected life of the energy storage inverter according to claim 1, characterized in that: When there are N power switch devices, N drive control modules are used for driving, each drive control module is driven by one PWM signal, and is uniformly gate-controlled by one gate signal.

6. The driving circuit for improving the expected life of the energy storage inverter according to claim 1, characterized in that: The resistor network is a combination of a resistor and a diode, including a first loop and a second loop connected in parallel; the first loop only includes a resistor, and the second loop includes a resistor and a diode connected in series.

7. A method for improving the expected life of an energy storage inverter, applied to the drive circuit for improving the expected life of an energy storage inverter according to any one of claims 1 to 6, comprising the following steps: The driving circuit of the power switch device adopts the driving circuit as described above to improve the expected life of the energy storage inverter; Setting a power degradation parameter and a threshold value of the power switch device; the degradation parameter includes at least one of an operating voltage, an output power and a junction temperature of the power switch device of the energy storage inverter; Periodically detecting power degradation parameters of power switching devices; When the power reduction parameter is greater than a set threshold, power reduction is performed by selecting a driving resistor with a larger resistance value through a selection signal or by reducing the frequency of a PWM signal.

8. The method for increasing the expected life of an energy storage inverter according to claim 7, characterized in that: When the power degradation parameter is the DC side voltage of the energy storage inverter, the power degradation is performed by adopting a gating signal to select a driving resistor with a larger resistance value.

9. The method for increasing the expected life of an energy storage inverter according to claim 7, characterized in that: When the power degradation parameter is the output power of the energy storage inverter, the power degradation is performed by reducing the frequency of the PWM signal.

10. The method for increasing the expected life of an energy storage inverter according to claim 7, characterized in that: When the power derating parameter is the junction temperature of the power switch device, the power derating is performed by selecting a driving resistor with a larger resistance through a selection signal and reducing the frequency of a PWM signal until shutdown protection is performed.

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