Grid driving improvement circuit and motor driving system

Abstract

The invention provides a grid driving improvement circuit and a motor driving system. The grid driving improvement circuit comprises a driving circuit, a first resistor, a second resistor, a diode, a third resistor, a first capacitor, a first inductor and an IGBT tube. The input end of the driving circuit is connected with a power supply, the output end of the driving circuit is connected with the first end of the first resistor and the first end of the second resistor, the second end of the first resistor is connected with the anode of the diode, and the second end of the second resistor is connected with the cathode of the diode, the first end of the first inductor and the first end of the third resistor. The second end of the third resistor is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the emitting electrode of the IGBT and is grounded, the second end of the first inductor is connected with the grid electrode of the IGBT, and the collector electrode of the IGBT is used for being connected with a signal output end. According to the invention, the conduction state of the IGBT is improved, di / dt and du / dt are reduced, and meanwhile, the conduction loss is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a gate drive improvement circuit and a motor drive system. Background Art

[0002] With the development of power electronics technology, IGBT intelligent power modules (IPM) are being used more and more widely. In high-power applications, IGBTs increase gate drive capabilities by push-pull power during high-speed on-off to achieve IGBT conduction.

[0003] The main function of the existing IGBT intelligent power module is to drive the motor or other power devices. It can achieve high efficiency, high stability, high reliability and easy-to-design power control. It is widely used in home appliances such as inverters, motor control, air conditioners, refrigerators, washing machines; as well as various industrial fields such as automotive parts, cleaning machines, elevators, etc.

[0004] However, in existing applications, by directly connecting the IGBT to the output end of the drive circuit, the gate drive of the IGBT has parasitic capacitance and stray inductance, the reverse recovery of the diode, di / dt (current rise rate), du / dt (voltage rise rate) and these parameters will have a great impact on the switching loss of the IGBT, resulting in inevitable losses, poor overall circuit reliability, and poor user experience. Summary of the invention

[0005] The present invention provides a gate drive improvement circuit, aiming to solve the problems of large gate drive loss, poor overall circuit reliability and poor user experience of the IGBT in the prior art.

[0006] In the first aspect, an embodiment of the present invention provides a gate drive improvement circuit, including a drive circuit, a first resistor, a second resistor, a diode, a third resistor, a first capacitor, a first inductor and an IGBT tube; the input end of the drive circuit is used to connect to a power supply, the output end of the drive circuit is respectively connected to the first end of the first resistor and the first end of the second resistor, the second end of the first resistor is connected to the positive electrode of the diode, the second end of the second resistor is respectively connected to the negative electrode of the diode, the first end of the first inductor and the first end of the third resistor, the second end of the third resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the emitter of the IGBT tube and grounded, the second end of the first inductor is connected to the gate of the IGBT tube, and the collector of the IGBT tube is used to connect to the signal output end.

[0007] Preferably, the gate drive improvement circuit further includes a fourth resistor, a first end of the fourth resistor is connected to the first end of the first inductor, and a second end of the fourth resistor is connected to the gate of the IGBT tube.

[0008] Preferably, the gate drive improvement circuit also includes a second capacitor and a third capacitor, the first end of the second capacitor is connected to the collector of the IGBT tube, and the second end of the second capacitor is connected to the gate of the IGBT tube; the first end of the third capacitor is connected to the emitter of the IGBT tube, and the second end of the third capacitor is connected to the gate of the IGBT tube.

[0009] Preferably, the driving circuit includes a driver and a power amplification unit, the positive input terminal of the driver is connected to the positive electrode of the power supply, the negative input terminal of the driver is connected to the negative electrode of the power supply, the output terminal of the driver is connected to the input terminal of the power amplification unit, and the output terminal of the power amplification unit serves as the output terminal of the driving circuit.

[0010] Preferably, the power amplification unit includes a first transistor and a second transistor, the base of the first transistor is connected to the base of the second transistor and serves as the input end of the power amplification unit, the collector of the first transistor is used to connect to the positive electrode of the power supply, the emitter of the first transistor is connected to the emitter of the second transistor and together serve as the output end of the power amplification unit, and the collector of the second transistor is used to connect to the negative electrode of the power supply.

[0011] Preferably, the gate drive improvement circuit further includes a fourth capacitor, a first end of which is respectively connected to the negative electrode of the power supply, the negative input terminal of the driver and the collector of the second transistor.

[0012] In a second aspect, an embodiment of the present invention provides a motor drive system for driving a compressor, comprising a rectifier circuit, a PFC circuit, a filter circuit, an inverter circuit, an auxiliary power supply, a control unit, a sensor, and the above-mentioned gate drive improvement circuit;

[0013] The auxiliary power supply is used to supply power to the control unit, the sensor is used to collect control signals, the control unit processes the control signals and sends them to the gate drive improvement circuit, and the gate drive improvement circuit outputs the control signals to the inverter circuit;

[0014] The input end of the rectifier circuit is used to connect to alternating current, and the output end of the rectifier circuit is connected to the PFC circuit, the filter circuit and the inverter circuit in sequence. The inverter circuit is used to drive and control the operation of the compressor.

[0015] Compared with the prior art, the beneficial effect of the present invention is that the input end of the driving circuit is used to connect the power supply, the output end of the driving circuit is respectively connected to the first end of the first resistor and the first end of the second resistor, the second end of the first resistor is connected to the positive electrode of the diode, the second end of the second resistor is respectively connected to the negative electrode of the diode, the first end of the first inductor and the first end of the third resistor, the second end of the third resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the emitter of the IGBT tube and grounded, the second end of the first inductor is connected to the gate of the IGBT tube, and the collector of the IGBT tube is used to connect the signal output end. In this way, a third resistor and a first capacitor are added between the gate and the emitter of the IGBT tube to suppress the resonance formed by the gate path equivalent inductance gate path and the gate path equivalent capacitance, and soften the startup and reduce the turn-on loss. The circuit improves the conduction state of the IGBT, softens the turn-on process, reduces di / dt and du / dt while reducing the driving resistance, and reduces the turn-on loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be described in detail below in conjunction with the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings. In the accompanying drawings:

[0017] Figure 1 is a circuit diagram of a gate drive improvement circuit provided by an embodiment of the present invention;

[0018] Figure 2 is a simulation diagram of a gate drive improvement circuit provided by an embodiment of the present invention;

[0019] Figure 3 It is a module diagram of a motor drive system provided by an embodiment of the present invention.

[0020] In the figure, 100, gate drive improvement circuit, 1, drive circuit, 11, driver, 12, power amplifier unit, 2, IGBT tube, 3, rectifier circuit, 4, PFC circuit, 5, filter circuit, 6, inverter circuit, 7, auxiliary power supply, 8, control unit, 9, sensor, 10, compressor. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] Embodiment 1

[0023] Combined with Figure 1-Figure 2As shown, an embodiment of the present invention provides a gate drive improvement circuit 100, including a drive circuit 1, a first resistor R1, a second resistor R2, a diode D1, a third resistor R3, a first capacitor C1, a first inductor L1 and an IGBT tube 2; the input end of the drive circuit 1 is used to connect to a power supply, the output end of the drive circuit 1 is respectively connected to the first end of the first resistor R1 and the first end of the second resistor R2, the second end of the first resistor R1 is connected to the positive electrode of the diode D1, the second end of the second resistor R2 is respectively connected to the negative electrode of the diode D1, the first end of the first inductor L1 and the first end of the third resistor R3, the second end of the third resistor R3 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is connected to the emitter of the IGBT tube 2 and grounded, the second end of the first inductor L1 is connected to the gate of the IGBT tube 2, and the collector of the IGBT tube 2 is used to connect to the signal output end.

[0024] Specifically, the turn-on loss is reduced by optimizing di / dt (current rise rate) and du / dt (voltage rise rate). Usually, in order to reduce di / dt, it is only necessary to adjust the first resistor R1, but when the first resistor R1 increases, it will affect du / dt, resulting in increased turn-on loss.

[0025] The present invention adds a first capacitor C1 between the gate and the emitter. The first capacitor C1 softens the turn-on process in the circuit. When turning off, the turn-on loss is reduced, di / dt and du / dt are reduced, and the turn-off loss is increased. However, the second resistor R2 for driving the turn-off can be adjusted to control the turn-off loss. After the capacitance is increased, resonance will be generated with the inductance on the gate side and the first inductor L1. In order to suppress the resonance, the present invention connects a third resistor R3 with a resistance lower than 1 ohm in series with the first capacitor C1 to suppress the resonance formed by the gate path equivalent inductance and the gate path and the gate path equivalent capacitance.

[0026] Through simulation Figure 2 , it can be observed that the C with different capacitance values G and without access to C G After the first capacitor C1 is connected, R Gon It can be clearly seen that after adding the softening first capacitor C1, du / dt is significantly reduced, and the turn-on loss is also significantly reduced. G represents the first capacitor C1, R Gon Represents the second resistor R2.

[0027] In this embodiment, the gate drive improvement circuit 100 further includes a fourth resistor R4 , a first end of the fourth resistor R4 is connected to the first end of the first inductor L1 , and a second end of the fourth resistor R4 is connected to the gate of the IGBT tube 2 .

[0028] In this embodiment, the gate drive improvement circuit 100 also includes a second capacitor C2 and a third capacitor C3, wherein the first end of the second capacitor C2 is connected to the collector of the IGBT tube 2, and the second end of the second capacitor C2 is connected to the gate of the IGBT tube 2; the first end of the third capacitor C3 is connected to the emitter of the IGBT tube 2, and the second end of the third capacitor C3 is connected to the gate of the IGBT tube 2.

[0029] In this embodiment, the driving circuit 1 includes a driver 11 and a power amplification unit 12, the positive input end of the driver 11 is connected to the positive electrode of the power supply, the negative input end of the driver 11 is connected to the negative electrode of the power supply, the output end of the driver 11 is connected to the input end of the power amplification unit 12, and the output end of the power amplification unit 12 serves as the output end of the driving circuit 1.

[0030] In this embodiment, the power amplification unit 12 includes a first transistor Q1 and a second transistor Q2, the base of the first transistor Q1 is connected to the base of the second transistor Q2 and serves as the input end of the power amplification unit 12, the collector of the first transistor Q1 is used to connect the positive electrode (15V) of the power supply, the emitter of the first transistor Q1 is connected to the emitter of the second transistor Q2 and together serve as the output end of the power amplification unit 12, and the collector of the second transistor Q2 is used to connect the negative electrode (-5V) of the power supply.

[0031] In this embodiment, the gate drive improvement circuit 100 further includes a fourth capacitor C4, and a first end of the fourth capacitor C4 is respectively connected to the negative electrode of the power supply, the negative input end of the driver 11 and the collector of the second transistor Q2.

[0032] Embodiment 2

[0033] like Figure 1-Figure 3 As shown, an embodiment of the present invention provides a motor drive system for driving a compressor 10, including a rectifier circuit 3, a PFC circuit 4, a filter circuit 5, an inverter circuit 6, an auxiliary power supply 7, a control unit 8, a sensor 9 and the above-mentioned gate drive improvement circuit 100.

[0034] The auxiliary power supply 7 is used to power the control unit 8, and the sensor 9 is used to collect control signals. The control unit 8 processes the control signals and sends them to the gate drive improvement circuit 100, which then outputs them to the inverter circuit 6.

[0035] The input end of the rectifier circuit 3 is used to connect to the alternating current, and the output end of the rectifier circuit 3 is connected to the PFC circuit 4, the filter circuit 5 and the inverter circuit 6 in sequence. The inverter circuit 6 is used to drive and control the compressor 10 to work.

[0036] Specifically, the application of the IPM intelligent power module requires rectification and filtering, and then the inverter circuit 6 is controlled by the unit control driver IC to drive the compressor 10 or the motor, and low noise and low power consumption are achieved during the inverter process. In the application circuit, a resistor less than 1 ohm is added to the gate drive circuit 1 of the lower bridge inside the module to suppress the resonance formed by the gate path equivalent inductance gate path and the gate path equivalent capacitance, and soften the startup to reduce the turn-on loss.

[0037] The control unit 8 is a MCU microprocessor. The rectifier circuit 3 is an AC-DC / DC-DC rectifier.

[0038] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, article or device. In the absence of more restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, article or device including the element.

[0039] The embodiments of the present invention are described above in conjunction with the accompanying drawings. What is disclosed is only the preferred embodiment of the present invention. However, the present invention is not limited to the above-mentioned specific implementation manner. The above-mentioned specific implementation manner is only illustrative rather than restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms and equivalent changes without departing from the scope of protection of the purpose of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A gate drive improvement circuit, characterized in that: It includes a drive circuit, a first resistor, a second resistor, a diode, a third resistor, a first capacitor, a first inductor and an IGBT tube; the input end of the drive circuit is used to connect to a power supply, the output end of the drive circuit is respectively connected to the first end of the first resistor and the first end of the second resistor, the second end of the first resistor is connected to the positive electrode of the diode, the second end of the second resistor is respectively connected to the negative electrode of the diode, the first end of the first inductor and the first end of the third resistor, the second end of the third resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the emitter of the IGBT tube and grounded, the second end of the first inductor is connected to the gate of the IGBT tube, and the collector of the IGBT tube is used to connect to the signal output end.

2. The gate drive improvement circuit according to claim 1, characterized in that: The gate drive improvement circuit further includes a fourth resistor, a first end of the fourth resistor is connected to the first end of the first inductor, and a second end of the fourth resistor is connected to the gate of the IGBT tube.

3. The gate drive improvement circuit according to claim 1, characterized in that: The gate drive improvement circuit also includes a second capacitor and a third capacitor, wherein the first end of the second capacitor is connected to the collector of the IGBT tube, and the second end of the second capacitor is connected to the gate of the IGBT tube; the first end of the third capacitor is connected to the emitter of the IGBT tube, and the second end of the third capacitor is connected to the gate of the IGBT tube.

4. The gate drive improvement circuit according to claim 1, characterized in that: The driving circuit includes a driver and a power amplification unit, the positive input terminal of the driver is connected to the positive electrode of the power supply, the negative input terminal of the driver is connected to the negative electrode of the power supply, the output terminal of the driver is connected to the input terminal of the power amplification unit, and the output terminal of the power amplification unit serves as the output terminal of the driving circuit.

5. The gate drive improvement circuit according to claim 4, characterized in that: The power amplification unit includes a first transistor and a second transistor, the base of the first transistor is connected to the base of the second transistor and serves as the input end of the power amplification unit, the collector of the first transistor is used to connect to the positive electrode of the power supply, the emitter of the first transistor is connected to the emitter of the second transistor and together serve as the output end of the power amplification unit, and the collector of the second transistor is used to connect to the negative electrode of the power supply.

6. The gate drive improvement circuit according to claim 5, characterized in that: The gate drive improvement circuit further includes a fourth capacitor, a first end of which is respectively connected to the negative electrode of the power supply, the negative input end of the driver, and the collector of the second transistor.

7. A motor drive system for driving a compressor, characterized in that: It comprises a rectifier circuit, a PFC circuit, a filter circuit, an inverter circuit, an auxiliary power supply, a control unit, a sensor and a gate drive improvement circuit as claimed in any one of claims 1 to 6; The auxiliary power supply is used to supply power to the control unit, the sensor is used to collect control signals, the control unit processes the control signals and sends them to the gate drive improvement circuit, and the gate drive improvement circuit outputs the control signals to the inverter circuit; The input end of the rectifier circuit is used to connect to alternating current, and the output end of the rectifier circuit is connected to the PFC circuit, the filter circuit and the inverter circuit in sequence. The inverter circuit is used to drive and control the operation of the compressor.

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