Low-loss inverter circuit based on high-frequency IGBT

Abstract

The utility model discloses a low-loss inverter circuit based on a high-frequency IGBT (Insulated Gate Bipolar Translator), which is provided with a control unit, an inverter circuit and a driving circuit, and the control unit controls the driving circuit to send a high-frequency signal to a high-frequency inverter module to carry out PWM (Pulse Width Modulation) rectification and output a direct-current voltage to a first filtering module; direct-current voltage is filtered through the first filtering module and the second filtering module, low-frequency sine waves corresponding to the direct-current voltage are output through the output module, switching loss can be reduced by adopting a high-frequency IGBT as the inverter circuit, sine pulse width modulation is adopted in the driving circuit, and the driving circuit and the high-frequency inverter circuit are combined to effectively modulate high-frequency signals. The high-frequency IGBT inverter circuit adopts RC filtering to filter and rectify the high-frequency IGBT inverter circuit, the output waveform is optimized, the circuit has the advantages of being high in integration level, low in temperature rise and few in harmonic wave, and the working stability of the circuit is improved.

Description

Technical Field

[0001] This utility model belongs to the field of power electronics technology, and in particular relates to a low-loss inverter circuit based on high-frequency IGBT. Background Technology

[0002] Currently, high-frequency inverters typically use high-frequency conversion technology to convert low-voltage DC power into high-frequency, low-voltage AC power. This AC power is then stepped up by a high-frequency transformer, rectified by a high-frequency rectifier and filter circuit to a high-voltage DC power of over 300V, and finally supplied to the load as 220V AC power via a power frequency inverter circuit. However, traditional 20kHz power frequency inverter circuits are bulky and heavy, resulting in increased switching losses and harmonic pollution in the output current. This necessitates the addition of filters, further increasing the manufacturing cost of the high-frequency inverter circuit. Therefore, it is necessary to provide a low-loss inverter circuit based on high-frequency IGBTs to address these technical problems. Utility Model Content

[0003] To address the aforementioned problems, this invention provides a low-loss inverter circuit based on high-frequency IGBTs. The use of high-frequency IGBTs can reduce switching losses, and features high integration and low temperature rise, while also reducing harmonic pollution, thus solving the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] This utility model provides a low-loss inverter circuit based on high-frequency IGBT, including a control unit, an inverter circuit, and a drive circuit. The control unit and the drive circuit are both connected to the inverter circuit, and the drive circuit is connected to the control unit.

[0006] The inverter circuit includes a high-frequency inverter module, a first filter module, a second filter module, and an output module. One end of the high-frequency inverter module is connected to the DC bus, and the other end of the high-frequency inverter module and the second filter module are both connected to the first filter module. The second filter module is connected to the output module.

[0007] The drive circuit includes a first isolation drive module and a second isolation drive module, both of which are connected to the high-frequency inverter module.

[0008] The control unit controls the drive circuit to send a high-frequency signal to the high-frequency inverter module for PWM rectification and outputs a DC voltage to the first filter module. The DC voltage is filtered by the first filter module and the second filter module and then output by the output module as a low-frequency sine wave.

[0009] As a preferred embodiment of the above technical solution, the high-frequency inverter module includes a first bridge arm circuit and a second bridge arm circuit. The first bridge arm circuit includes a power switch Q1, a resistor R5, a power switch Q3, and a resistor R15. The drain of the power switch Q1 is connected to the input terminal of the DC bus. The gate of the power switch Q1 is connected to one end of the resistor R5. The other end of the resistor R5 is connected to the source of the power switch Q1 and the drain of the power switch Q3. The gate of the power switch Q3 is connected to one end of the resistor R15. The source of the power switch Q3 is connected to the other end of the resistor R15 and grounded. The second isolation drive module is connected to the midpoint VHS1 of the first bridge arm circuit.

[0010] The second bridge arm circuit includes a power switch Q2, a resistor R6, a power switch Q4, and a resistor R16. The drain of the power switch Q2 is connected to the input terminal of the DC bus. The gate of the power switch Q2 is connected to one end of the resistor R6. The other end of the resistor R6 is connected to the source of the power switch Q2 and the drain of the power switch Q4. The gate of the power switch Q4 is connected to one end of the resistor R16. The other end of the resistor R16 is connected to the source of the power switch Q4 and grounded. The first isolation drive module is connected to the midpoint VHS2 of the second bridge arm circuit.

[0011] As a preferred embodiment of the above technical solution, the first filtering module includes an inductor L1 and a capacitor C2. One end of the inductor L1 is connected to the second bridge arm circuit, and the other end of the inductor L1 is connected to the capacitor C2. The capacitor C2 is connected to the first bridge arm circuit.

[0012] As a preferred embodiment of the above technical solution, the capacitor C2 is a thin-film capacitor, and the inductor L1 is made of a toroidal iron-silicon-aluminum magnetic core.

[0013] As a preferred embodiment of the above technical solution, the second filtering module includes inductor L2, inductor L3 and capacitor CX1. Inductor L2 and inductor L3 are both common-mode inductors. Capacitor CX1 is located between inductor L2 and inductor L3. One end of inductor L2 is connected to inductor L1, capacitor C2 and the first bridge arm circuit. The other end of inductor L2 is connected to capacitor CX1 and one end of inductor L3. Inductor L3 is connected to the output module.

[0014] As a preferred embodiment of the above technical solution, the first isolation driving module includes a chip U2 and a first peripheral circuit connected to the chip U2, and the second isolation driving module includes a chip U3 and a second peripheral circuit connected to the chip U3. Both the first peripheral circuit and the second peripheral circuit include multiple resistors, multiple capacitors and multiple diodes.

[0015] As a preferred embodiment of the above technical solution, when power switch Q1 and power switch Q4 are turned on, the high-frequency inverter module outputs a positive DC voltage; when power switch Q2 and power switch Q3 are turned on, the high-frequency inverter module outputs a negative DC voltage.

[0016] As a preferred embodiment of the above technical solution, the control unit controls the second isolation drive module to emit a 100kHz high-frequency wave, the control unit controls the first isolation drive module to emit a 50kHz high-frequency wave, and the low-frequency sine wave has a frequency of 50Hz.

[0017] As a preferred embodiment of the above technical solution, the model of the chip U2 and the chip U3 is CA-IS3221BW.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] By setting up a control unit, an inverter circuit, and a drive circuit, the control unit controls the drive circuit to send a high-frequency signal to the high-frequency inverter module for PWM rectification and output a DC voltage to the first filter module. The DC voltage is filtered by the first and second filter modules and then output as a low-frequency sine wave corresponding to the DC voltage through the output module. Using a high-frequency IGBT as the inverter circuit can reduce switching losses. The drive circuit uses sinusoidal pulse width modulation. The combination of the drive circuit and the high-frequency inverter circuit can effectively modulate the high-frequency signal and reduce crossover distortion. RC filtering is used to filter and rectify the high-frequency IGBT inverter circuit, optimizing the output waveform. The circuit has the characteristics of high integration, low temperature rise, and few harmonics, which improves the working stability of the circuit. Attached Figure Description

[0020] Figure 1 This is a block diagram of the low-loss inverter circuit based on high-frequency IGBT proposed in this utility model.

[0021] Figure 2 This is a circuit diagram of the inverter circuit proposed in this utility model;

[0022] Figure 3 This is a circuit diagram of the first isolation drive module proposed in this utility model;

[0023] Figure 4 This is a circuit diagram of the second isolation drive module proposed in this utility model.

[0024] The symbols for the main components are explained below:

[0025] 10-Control unit; 20-Inverter circuit; 21-High frequency inverter module; 211-First bridge arm circuit; 212-Second bridge arm circuit; 22-First filter module; 23-Second filter module; 24-Output module; 30-Drive circuit; 31-First isolation drive module; 32-Second isolation drive module. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0027] See Figure 1 , Figure 2 , Figure 3 and Figure 4 This utility model provides a low-loss inverter circuit based on high-frequency IGBT, including a control unit 10, an inverter circuit 20 and a drive circuit 30. The control unit 10 and the drive circuit 30 are both connected to the inverter circuit 20, and the drive circuit 30 is connected to the control unit 10.

[0028] The inverter circuit 20 includes a high-frequency inverter module 21, a first filter module 22, a second filter module 23, and an output module 24. One end of the high-frequency inverter module 21 is used to connect to the DC bus. The other end of the high-frequency inverter module 21 and the second filter module 23 are both connected to the first filter module 22. The second filter module 23 is connected to the output module 24.

[0029] The drive circuit 30 includes a first isolation drive module 31 and a second isolation drive module 32, both of which are connected to the high-frequency inverter module 21.

[0030] The control unit 10 controls the drive circuit 30 to send a high-frequency signal to the high-frequency inverter module 21 for PWM rectification and output a DC voltage to the first filter module 22. The DC voltage is filtered by the first filter module 22 and the second filter module 23 and then output by the output module 24 as a low-frequency sine wave corresponding to the DC voltage.

[0031] In this embodiment, the high-frequency inverter module 21 includes a first bridge arm circuit 211 and a second bridge arm circuit 212. The first bridge arm circuit 211 includes a power switch Q1, a resistor R5, a power switch Q3, and a resistor R15. The drain of the power switch Q1 is connected to the input terminal of the DC bus. The gate of the power switch Q1 is connected to one end of the resistor R5. The other end of the resistor R5 is connected to the source of the power switch Q1 and the drain of the power switch Q3. The gate of the power switch Q3 is connected to one end of the resistor R15. The source of the power switch Q3 is connected to the other end of the resistor R15 and grounded. The second isolation drive module 32 is connected to the... The first bridge arm circuit 211 is connected at the midpoint VHS1; the second bridge arm circuit 212 includes a power switch Q2, a resistor R6, a power switch Q4, and a resistor R16. The drain of the power switch Q2 is connected to the input terminal of the DC bus, the gate of the power switch Q2 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the source of the power switch Q2 and the drain of the power switch Q4, the gate of the power switch Q4 is connected to one end of the resistor R16, the other end of the resistor R16 is connected to the source of the power switch Q4 and grounded, and the first isolation drive module 31 is connected to the midpoint VHS2 of the second bridge arm circuit 32.

[0032] Specifically, the control unit 10 is a DSP chip, and the output module 24 includes terminals J1 and J2. Pin 1 of chip U2 is connected to one end of resistor R21, capacitor C13, and resistor R27; pin 2 of chip U2 is connected to one end of resistor R24, capacitor C12, and resistor R26; pin 3 of chip U2 is connected to capacitor C16; pin 5 of chip U2 is connected to resistor R29; pin 6 of chip U2 is connected to capacitor C14 and resistor R30; pin 15 of chip U2 is connected to capacitor C15; and the other ends of resistors R21 and R24 are connected to the DSP chip. Pins 16 and 14 of chip U2 are connected to capacitor C17, and pin 15 of chip U2 is connected to capacitor J2. Connect one end of resistor R20 and one end of resistor R23. Connect the other end of resistor R20 to the cathode of diode D2. Connect the other end of resistor R23 to the anode of diode D2, the gate of power switch Q4, and the junction of resistor R16. Connect pins 9 and 11 of chip U2 to one end of capacitor C11. Connect the other end of capacitor C11 to the cathode of diode D5. Connect the anode of diode D5 to resistor R19. Connect pin 10 of chip U2 to one end of resistor R25 and one end of resistor R28. Connect the other end of resistor R25 to the cathode of diode D4. Connect the other end of resistor R28 to the anode of diode D4, the gate of power switch Q2, and the junction of resistor R6.

[0033] Specifically, pin 1 of chip U3 is connected to one end of resistor R35, capacitor C22, and resistor R41; pin 2 of chip U3 is connected to one end of resistor R39 and resistor R40; the other ends of resistors R35 and R39 are connected to chip DSP; pin 5 of chip U3 is connected to resistor R44; pin 6 of chip U3 is connected to capacitor C23 and resistor R45; pins 3 and 8 of chip U3 are connected to capacitors C27 and C25; pin 16 of chip U3 is connected to capacitors C18 and C21, and the cathode of diode D6; diode D... The anode of diode 6 is connected to resistor R31. Pin 15 of chip U3 is connected to one end of resistor R34 and one end of resistor R36. The other end of resistor R34 is connected to the cathode of diode D7. The anode of diode D7 and the other end of resistor R36 are connected to the gate of power switch Q1 and the junction with resistor R5. Pin 10 of chip U3 is connected to one end of resistor R42 and one end of resistor R43. The other end of resistor R42 is connected to the cathode of diode D8. The other end of resistor R43 and the anode of diode D8 are connected to the gate of power switch Q3 and the junction with resistor R15.

[0034] The inverter circuit 20 uses a high-frequency IGBT, specifically the latest SUPER high-frequency IGBT SIW60N65G2HP2A (650V / 60A, maximum switching frequency 240kHz), with Vce = 1.75V. Switching losses are reduced by 35% compared to traditional IGBTs. The drive circuit 30 uses the CA-IS3221BW driver chip, with 5.7kVRMS (wide-body package) isolation voltage, built-in Miller clamping and overcurrent protection, and a drive voltage of ±15V. The drive circuit 30 can employ SPWM (Sinusoidal Pulse Width Modulation) with a high-frequency loop frequency of 100kHz, optimizing the dead time to 0.8μs to reduce crossover distortion. It uses an LC filter, and the film capacitor is a WIMA MKP1848, 400V / 4.7μF, with an equivalent series resistance (ESR) ≤ 8mΩ. The inductor uses a toroidal iron-silicon-aluminum core (permeability 60), with an inductance of 330μH / 100kHz, and its size is 50% smaller than that of a power frequency inductor. The PWM dead time prevents two devices from conducting simultaneously; that is, when one device is off, a dead time is required before the other (power switch) can be turned on.

[0035] It should be noted that the first filtering module 22 includes an inductor L1 and a capacitor C2. One end of inductor L1 is connected to the second bridge arm circuit, and the other end of inductor L1 is connected to capacitor C2. Capacitor C2 is connected to the first bridge arm circuit 211. The capacitor C2 is a thin-film capacitor, and the inductor L1 is made of a toroidal iron-silicon-aluminum magnetic core. The second filtering module 23 includes an inductor L2, an inductor L3, and a capacitor CX1. Inductors L2 and L3 are both common-mode inductors. Capacitor CX1 is located between inductors L2 and L3. One end of inductor L2 is connected to inductor L1, capacitor C2, and the first bridge arm circuit 211, and the other end of inductor L2 is connected to capacitor CX1 and one end of inductor L3. Inductor L3 is connected to the output module 24. The first isolation driving module 31 includes a chip U2 and a first peripheral circuit connected to chip U2. The second isolation driving module 32 includes a chip U3 and a second peripheral circuit connected to chip U3. Both the first and second peripheral circuits include multiple resistors, multiple capacitors, and multiple diodes.

[0036] Specifically, when power switches Q1 and Q4 are turned on, the high-frequency inverter module 21 outputs a positive DC voltage; when power switches Q2 and Q3 are turned on, the high-frequency inverter module 21 outputs a negative DC voltage. The control unit 10 controls the second isolation drive module 32 to emit a 100kHz high-frequency wave, and the control unit 10 controls the first isolation drive module 31 to emit a 50kHz high-frequency wave. The low-frequency sine wave has a frequency of 50Hz. The model numbers of chips U2 and U3 are CA-IS3221BW. In other words, when power switches Q1 and Q4 are turned on, the H-bridge outputs a DC voltage; when power switches Q2 and Q3 are turned on, the H-bridge outputs a negative DC voltage. Alternating this process, the H-bridge outputs positive and negative square waves, which, after passing through the filter circuits L1 and C2, yield an AC sinusoidal voltage. INV_FL_DSP and INV_FH_DSP emit a 100kHz high-frequency wave through the DSP, which, through the isolation driver U2, performs PWM control on Q2 and Q4. INV_SL_DSP and INV_SH_DSP emit a 50kHz high-frequency wave through the DSP, which, through the isolation driver U2, performs PWM control on Q1 and Q3, ultimately outputting a 50Hz sine wave.

[0037] It is worth noting that traditional 20kHz power frequency inverter circuits have the following drawbacks: the 3kW module measures 120×180×80mm and weighs over 2kg; switching losses account for 35% of the total losses, resulting in an efficiency below 95%; the output current THD (Total Harmonic Distortion) is greater than 5%, requiring an additional filter; magnetic components and the heat dissipation system account for 30% of the total cost. Harmonic distortion is caused by the system's non-linearity, and the sum of all additional harmonic levels is called total harmonic distortion, which is frequency-dependent. The drive circuit in this application, by optimizing the PWM duty cycle, reduces THD to below 1.5% and uses IGBT complementary wave generation to reduce dead time and rectification losses.

[0038] Specifically, the low-loss inverter circuit of this application adopts a DC 400V input voltage and an output power of 3KW, with an efficiency of 98.3% at full load. The test verification results are as follows: (1) Temperature rise test: using an infrared thermal imager (FLIR T1020), the IGBT junction temperature is stable below 85℃; (2) Harmonic test: THD is measured by a Keysight DSOX1204G oscilloscope, and the output harmonics are <1.5%. In summary, the low-frequency inverter circuit of this application optimizes the selection of components for 3kW applications, balances performance and cost, adopts an integrated design of planar transformer and LC filter to reduce space occupation, and combines synchronous rectification and soft switching technology to improve efficiency to 98.3%. It can be applied to industrial welding machines (which can be integrated into portable devices after size reduction) and photovoltaic energy storage (reducing inverter costs and promoting the popularization of household energy storage).

[0039] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A low-loss inverter circuit based on high-frequency IGBTs, characterized in that, It includes a control unit, an inverter circuit, and a drive circuit. The control unit and the drive circuit are both connected to the inverter circuit, and the drive circuit is connected to the control unit. The inverter circuit includes a high-frequency inverter module, a first filter module, a second filter module, and an output module. One end of the high-frequency inverter module is connected to the DC bus, and the other end of the high-frequency inverter module and the second filter module are both connected to the first filter module. The second filter module is connected to the output module. The drive circuit includes a first isolation drive module and a second isolation drive module, both of which are connected to the high-frequency inverter module. The control unit controls the drive circuit to send a high-frequency signal to the high-frequency inverter module for PWM rectification and outputs a DC voltage to the first filter module. The DC voltage is filtered by the first filter module and the second filter module and then output by the output module as a low-frequency sine wave.

2. The low-loss inverter circuit based on high-frequency IGBT according to claim 1, characterized in that, The high-frequency inverter module includes a first bridge arm circuit and a second bridge arm circuit. The first bridge arm circuit includes a power switch Q1, a resistor R5, a power switch Q3, and a resistor R15. The drain of the power switch Q1 is connected to the input terminal of the DC bus. The gate of the power switch Q1 is connected to one end of the resistor R5. The other end of the resistor R5 is connected to the source of the power switch Q1 and the drain of the power switch Q3. The gate of the power switch Q3 is connected to one end of the resistor R15. The source of the power switch Q3 is connected to the other end of the resistor R15 and grounded. The second isolation drive module is connected to the midpoint VHS1 of the first bridge arm circuit. The second bridge arm circuit includes a power switch Q2, a resistor R6, a power switch Q4, and a resistor R16. The drain of the power switch Q2 is connected to the input terminal of the DC bus. The gate of the power switch Q2 is connected to one end of the resistor R6. The other end of the resistor R6 is connected to the source of the power switch Q2 and the drain of the power switch Q4. The gate of the power switch Q4 is connected to one end of the resistor R16. The other end of the resistor R16 is connected to the source of the power switch Q4 and grounded. The first isolation drive module is connected to the midpoint VHS2 of the second bridge arm circuit.

3. The low-loss inverter circuit based on high-frequency IGBT according to claim 2, characterized in that, The first filtering module includes an inductor L1 and a capacitor C2. One end of the inductor L1 is connected to the second bridge arm circuit, and the other end of the inductor L1 is connected to the capacitor C2. The capacitor C2 is connected to the first bridge arm circuit.

4. The low-loss inverter circuit based on high-frequency IGBT according to claim 3, characterized in that, The capacitor C2 is a thin-film capacitor, and the inductor L1 is made of a toroidal iron-silicon-aluminum magnetic core.

5. The low-loss inverter circuit based on high-frequency IGBT according to claim 3, characterized in that, The second filtering module includes inductor L2, inductor L3 and capacitor CX1. Inductor L2 and inductor L3 are both common-mode inductors. Capacitor CX1 is located between inductor L2 and inductor L3. One end of inductor L2 is connected to inductor L1, capacitor C2 and the first bridge arm circuit. The other end of inductor L2 is connected to capacitor CX1 and one end of inductor L3. Inductor L3 is connected to the output module.

6. The low-loss inverter circuit based on high-frequency IGBT according to claim 5, characterized in that, The first isolation driver module includes a chip U2 and a first peripheral circuit connected to the chip U2. The second isolation driver module includes a chip U3 and a second peripheral circuit connected to the chip U3. Both the first peripheral circuit and the second peripheral circuit include multiple resistors, multiple capacitors and multiple diodes.

7. The low-loss inverter circuit based on high-frequency IGBT according to claim 6, characterized in that, When power switches Q1 and Q4 are turned on, the high-frequency inverter module outputs a positive DC voltage; when power switches Q2 and Q3 are turned on, the high-frequency inverter module outputs a negative DC voltage.

8. The low-loss inverter circuit based on high-frequency IGBT according to claim 1, characterized in that, The control unit controls the second isolation drive module to emit a 100kHz high-frequency wave, and the control unit controls the first isolation drive module to emit a 50kHz high-frequency wave. The frequency of the low-frequency sine wave is 50Hz.

9. The low-loss inverter circuit based on high-frequency IGBT according to claim 6, characterized in that, The model number of the chips U2 and U3 is CA-IS3221BW.

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