CN111585424A

CN111585424A - Power device drive circuit and inverter circuit

Info

Publication number: CN111585424A
Application number: CN202010527809.5A
Authority: CN
Inventors: 杨永江
Original assignee: Huaxinwei Semiconductor Technology Beijing Co ltd
Current assignee: Huaxinwei Semiconductor Technology Beijing Co ltd
Priority date: 2020-06-11
Filing date: 2020-06-11
Publication date: 2020-08-25

Abstract

The invention relates to the technical field of semiconductors, in particular to a driving circuit and an inverter circuit of a power device. The invention has the advantages that the SiC diodes are connected in parallel with small recovery current, the conduction loss and the recovery loss can be obviously reduced under the condition of not increasing the MHz frequency band noise, and the loss and the noise of the inverter can be reduced. The invention provides a switching circuit and an inverter circuit of a power semiconductor device including a silicon IGBT and a module in which the IGBT and the SiC diode are combined, wherein a resistance on a gate is set to be smaller than a resistance under the gate.

Description

Power device drive circuit and inverter circuit

Technical Field

The invention relates to the technical field of semiconductors, in particular to a driving circuit and an inverter circuit of a power device. Including a power semiconductor switching device connected in parallel with a spinning diode having a small reverse recovery current, such as a schottky barrier diode of a wide bandgap semiconductor (e.g., SiC and GaN) or a PiN diode of a wide bandgap semiconductor, and an inverter circuit including the spinning diode.

Background

In the related art, fig. 5 shows a circuit diagram of a common inverter using IGBTs (insulated gate bipolar transistors). The inverter consists of six IGBTs and diodes, and supplies power to the load motor from a main circuit power supply through the alternate switching of the upper and lower arm IGBTs. The IGBT and the diode in the inverter device need to reduce conduction loss and switching loss. In order to reduce such loss, it is necessary to improve the structure of the IGBT, reduce the on-voltage, or improve the drive circuit of the IGBT so that the IGBT can be driven at high speed. As the diode, a PiN diode formed of Si is generally used.

In the related art, fig. 6 shows a circuit diagram corresponding to a single-phase IGBT, and a recovery waveform of an upper diode and a turn-on waveform of a lower IGBT when the lower IGBT turns on. The IGBT is driven at a higher speed (solid line waveform) than a normal driving speed (dotted line waveform), so that di/dt in the IGBT conducting process is improved, and conducting loss and recovery loss are reduced. However, di/dt of the PiN diode reverse recovery also increases, and a current change (reverse recovery di/dt) during the decay of the PiN diode reverse recovery current is multiplied by the main circuit inductance L to generate a commutation surge (Δ Vp ═ lx reverse recovery di/dt), wherein the power semiconductor device may be damaged when the sum (E + Δvp) of the supply voltage (E) and the surge voltage (Δ Vp) exceeds the withstand voltage of the power semiconductor switching device. Therefore, a process of reducing the main circuit inductance and a process of changing the conduction di/dt have been proposed.

The prior document discloses a technique for detecting the recovery current of a free-wheeling diode, switching the conduction di/dt in two steps, thereby reducing the conduction loss and surge voltage.

In addition, the prior art document discloses a technique of controlling the driving speed of the turn-on gate in three steps (high speed, low speed, and high speed) to solve the problem of high dv/dt generated when the turn-on di/dt is set to high speed, which generates noise above a few mhz to cause malfunction of peripheral devices, achieving noise reduction in a high frequency band and reduction in loss.

As described above, according to the prior art IGBT inverter and the previously disclosed invention, it is attempted to reduce conduction loss and surge voltage or reduce noise and loss in a high frequency range by changing the gate charging speed. However, the Si-PiN diode has some drawbacks in that a recovery current becomes large when a large current is conducted, and a large surge voltage is generated when a small current is conducted for a short time.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The present invention aims to provide a drive circuit for a semiconductor device using a schottky barrier diode (such as silicon carbide (SiC) and gallium nitride (GaN)) which is a novel wide band gap semiconductor used in place of Si to drive a gate at high speed.

The power device driving circuit includes: a power semiconductor switching device and a freewheeling diode with a small reverse recovery current, wherein the resistance on the gate of the power semiconductor switching device is set smaller than its resistance under the gate.

As a further technical scheme, the method comprises the following steps:

l for line inductance of power semiconductor device and gate drive circuit_gWhen expressed, R is used as the buried resistance of the power semiconductor device_ginThe input capacitance of the power semiconductor device is represented by C_iesThe on-resistance of the power semiconductor switching device is represented by R_gonIt is shown that the on-resistance satisfies the following condition:

as a further technical solution, a capacitor is provided in parallel with a gate resistance of the power semiconductor switching device as a means for realizing high-speed driving.

As a further aspect, the freewheel diode with a small reverse recovery current includes a schottky barrier diode of a wide bandgap semiconductor.

As a further technical solution, the free-wheeling diode with small reverse recovery current includes a PiN diode of a wide bandgap semiconductor.

As a further aspect, the wide bandgap semiconductor includes: SiC and GaN.

The invention provides a power device inverter circuit, which comprises a power semiconductor switching device, a self-rotation diode with small reverse recovery current and a power semiconductor module, wherein the self-rotation diode is connected with the power semiconductor switching device; the power semiconductor module has a power switching device and a free-wheeling diode, and a gate drive circuit of the power semiconductor switching device, wherein a first high-voltage-side terminal of the power semiconductor switching device of the power semiconductor module and a second high-voltage-side terminal of a Schottky barrier diode of a wide bandgap semiconductor are independently arranged, and an inductance is provided between the first high-voltage-side terminal and the second high-voltage-side terminal.

As a further technical solution, the gate driving speed of the power semiconductor module is connected in parallel with a free-wheeling diode having a small reverse recovery current.

By adopting the technical scheme, the invention has the following beneficial effects:

the power device driving circuit and the inverter circuit provided by the invention have the advantages that the SiC diodes are connected in parallel with small recovery current, the conduction loss and the recovery loss can be obviously reduced under the condition of not increasing the MHz frequency band noise, and the loss and the noise of the inverter can be reduced. The invention provides a switching circuit and an inverter circuit of a power semiconductor device including a silicon IGBT and a module in which the IGBT and the SiC diode are combined, wherein a resistance on a gate is set to be smaller than a resistance under the gate.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a block diagram of a driving circuit of a power semiconductor device according to a first embodiment of the present invention;

fig. 2 shows waveforms of voltage, current and loss when the first embodiment according to the present invention is applied;

fig. 3 illustrates an effect of reducing loss when the first embodiment according to the present invention is applied;

fig. 4 shows the evaluation result of noise in the MHz band when the first embodiment according to the present invention is applied;

FIG. 5 is a diagram of an inverter circuit according to the prior art;

fig. 6 shows waveforms of voltage, current and loss using a power module embedded in a PiN diode according to the prior art;

fig. 7 is a block diagram of a driving circuit of a power semiconductor device according to a second embodiment of the present invention;

FIG. 8 is a gate drive voltage waveform according to a second embodiment of the present invention;

fig. 9 is a block diagram of an inverter circuit according to a third embodiment of the present invention;

fig. 10 is an equivalent circuit diagram of a main circuit of an inverter according to a third embodiment of the present invention;

fig. 11 is a block diagram of an inverter circuit according to a third embodiment of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

Example 1

Fig. 1 is a block diagram of a driving circuit of a power semiconductor device according to a first preferred embodiment of the present invention. The main circuit of the inverter is composed of Si IGBT21 and SiC SBD 22. The Si-IGBT has a buried resistance (R)_gin)23 and an IGBT input capacitance (C) built in the IGBT_ies)24. The Si-

IGBTs

21 and 22 of the main circuit are driven by the drive circuit 19 and the drive circuit power supply 20 according to the invention. According to the present drive circuit, the side gate resistance 11 is set smaller than the side gate resistance 12.

The SiC SBD 22 has a breakdown voltage strength of about 10 times that of Si, and therefore, the drift layer for ensuring withstand voltage can be reduced to about 1/10, and the power-on voltage of the power device can be reduced. Therefore, SiC and other wide bandgap semiconductor devices can use unipolar devices even if only the high-voltage resistance region of bipolar devices can be used in silicon semiconductor devices.

Fig. 2 shows an IGBT circuit diagram corresponding to a single phase, and a recovery waveform of the upper diode and a conduction waveform of the lower IGBT when the lower IGBT conducts. The dashed waveform illustrates the case where the turn-on speed of the IGBT is not increased.

Compared with fig. 6, when the Si-PiN diode of fig. 6 is used, the recovery loss of the present embodiment is reduced to 1/10, the conduction loss is reduced to 1/2, the acceleration increases the di/dt of the reverse recovery of the PiN diode, the multiplication with the main circuit inductance L generates a commutation surge (Δ Vp ═ lx reverse recovery di/dt), when the sum (E + Δvp) of the power supply voltage (E) and the surge voltage (Δ Vp) exceeds the withstand voltage of the power semiconductor switching device, as shown by the solid line waveform, the reverse recovery current is not generated at the time of acceleration, and a large surge voltage is not generated in the recovery voltage, thereby making it possible to increase the speed when the SiC SBD 22 is used.

Figure 3 shows the effect of reducing losses when the device is operated as an inverter. By replacing the Si-PiN diode with SiC SBD, the recovery loss can be reduced to 1/10 and the turn-on loss can be reduced to 1/2. In addition, by driving the IGBT at high speed, the conduction loss can be further reduced from 1/2 to 1/5.

Fig. 4 shows the actual measurement results of noise in the MHz band when driving a 200kw class inverter using six modules combining Si-IGBT and SiC-SBD. Even when acceleration is performed, there is no noise increase in the MHz band. Since the recovery current is substantially zero, ringing noise accompanied by a high-speed driver is rarely transmitted to the outside. Therefore, by using SiC SBD, on-resistance is reduced, high-speed driving is performed, and on-loss can be reduced without increasing MHz band noise.

Furthermore, the value of the on-gate resistor 11 should preferably be chosen to satisfy the condition that the gate circuit does not resonate. According to this condition, the circuit is an LRC resonant circuit in which the resistance on the gate (Rg) is₁₁)11 and gate line inductance (L)_g)10 IGBT buried resistor (R)_gin) And IGBT input capacitance (C)_ies) In series, wherein the circuit must satisfy the condition that no resonance occurs. As formula 1:

has the following characteristic values:

the conditions for achieving over-damping without gate vibration are:

therefore, the on-resistance must satisfy expression (3).

In the present embodiment, a Si-IGBT is used as the switching device, but the switching device may be a MOSFET in the case of Si, and may be a MOSFET, a junction FET, or a bipolar transistor in the case of SiC. Further, the present embodiment employs SiC SBDs as the parallel diodes, but similar effects can be achieved by SBDs employing wide bandgap semiconductors (e.g., GaN and diamond), PiN diodes, or diodes having an MPS (merged schottky barrier) structure in which the SBD and PiN diodes are combined.

Example 2

Fig. 7 shows a block diagram of a driving circuit of a power semiconductor device according to a second preferred embodiment of the present invention. The same reference numerals are used to denote the same components as in embodiment 1. According to the drive circuit of the present invention, in addition to the opposite-side gate resistance 11 being smaller than the opposite-side gate resistance 12, the flying capacitor 18 is provided in parallel with the opposite-side gate resistance 11.

Fig. 8 shows a gate voltage waveform of a driving circuit according to a second embodiment of the present invention. The gate input capacitance is set to 110nC, the gate buried resistance is set to 1.0 Ω, the side gate resistance is set to 1.0 Ω, and the on time from the gate voltage rise time is 0.5 μ s, that is, when the flying capacitor 18 is not provided, the on time from the gate voltage rise time can be reduced to about half or 0.3 μ s, and high-speed driving of the IGBT becomes possible by providing the flying capacitor of 12 μ F.

Example 3

Fig. 9 shows a block diagram of an inverter circuit according to a third preferred embodiment of the present invention. The same components as those in embodiment 1 are denoted by the same reference numerals. According to the present inverter, the power modules 25 are connected in series to constitute a portion corresponding to a single phase of the inverter. The inverter also includes a main circuit power supply 33 of the inverter, and

parasitic inductances

34 and 35 arranged between the power supply module 25 and the main circuit power supply 33. According to the power supply module 25 of the present invention, the high-voltage-side terminal 51 of the IGBT and the high-voltage-side terminal 52 of the SiC SBD are separately provided, and the inductance 31 is provided between the high-voltage-side terminal 51 of the IGBT and the high-voltage-side terminal 52 of the sicsbd.

Fig. 10 shows an equivalent circuit diagram of the main circuit of the inverter. The sum of

parasitic inductances

34 and 35 is called L_sThe output capacitance 42 of the IGBT and SiC SBD is referred to as C_oesThe on-resistance 41 of the IGBT is referred to as R_on. Further, the inductance 31 between the high-voltage-side terminal 51 of the IGBT and the high-voltage-side terminal 52 of the SiC SBD is referred to as L_m。

When L is not provided_mA frequency band close to 9Mhz, which is a vibration frequency specific to SiC SBD, is observed, as shown in fig. 4. This vibration frequency is determined by the following expression:

on the other hand, when the inductance 31 increases, the resonance frequency may move to the low frequency side, but the peak value of the resonance voltage increases, and may diverge. The circuit equation is expressed by expression (5):

in order to avoid such oscillation conditions, the condition of the over-damping is expressed by the following expression (6).

Therefore, by adopting the resonance frequency of expression (4) while satisfying expression (6), it is possible to drive the IGBT at high speed and significantly reduce loss without affecting noise of the MHz band by additionally providing the inductance 31.

According to fig. 11, the inductance 32 is provided between the low-voltage-side terminal 53 of the IGBT and the low-voltage-side terminal 54 of the SiC SBD, but in this case, while satisfying expression (6), a low-loss and low-noise inverter can be realized by adopting the resonance frequency of expression (4).

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power device driving circuit, comprising: a power semiconductor switching device and a freewheeling diode with a small reverse recovery current, wherein the resistance on the gate of the power semiconductor switching device is set smaller than its resistance under the gate.

2. The power device driving circuit according to claim 1, comprising:

3. the power device driving circuit according to claim 1, wherein a capacitor thereof is provided in parallel with a gate resistance of the power semiconductor switching device as a means for realizing high-speed driving.

4. The power device driving circuit according to claim 1, wherein the freewheel diode having a small reverse recovery current comprises a schottky barrier diode of a wide bandgap semiconductor.

5. The power device driving circuit according to claim 1, wherein the freewheel diode with small reverse recovery current comprises a PiN diode of a wide bandgap semiconductor.

6. The power device driving circuit according to claim 4 or 5, wherein the wide bandgap semiconductor comprises: SiC and GaN.

7. A power device inverter circuit is characterized by comprising a power semiconductor switching device, a self-rotation diode with small reverse recovery current and a power semiconductor module; the power semiconductor module has a power switching device and a free-wheeling diode, and a gate drive circuit of the power semiconductor switching device, wherein a first high-voltage-side terminal of the power semiconductor switching device of the power semiconductor module and a second high-voltage-side terminal of a Schottky barrier diode of a wide bandgap semiconductor are independently arranged, and an inductance is provided between the first high-voltage-side terminal and the second high-voltage-side terminal.

8. The power device inverter circuit according to claim 7, wherein the freewheeling diode having a small reverse recovery current comprises a schottky barrier diode of a wide bandgap semiconductor.

9. The power device inverter circuit of claim 7, wherein the freewheeling diode having a small reverse recovery current comprises a PiN diode of a wide bandgap semiconductor.

10. The power device inverter circuit according to claim 7,

the gate driving speed of the power semiconductor module is connected in parallel with a free-wheeling diode having a small reverse recovery current.