A circuit for driving a three-phase motor

Abstract

The present invention provides a circuit for driving a three-phase motor, which includes a rectifier bridge module disposed on a circuit board and a Boost-PFC module, a three-phase inverter module, and a driving module that are integrally disposed on the same DBC board. The DBC board is electrically connected to the side surface of the circuit board by using the same pair of pin groups. The AC input terminal of the rectifier bridge module is connected to the commercial power supply. The DC input terminal of the Boost-PFC module is connected to the DC output terminal of the rectifier bridge module. The DC input terminal of the three-phase inverter module is connected to the DC output terminal of the Boost-PFC module, and the three AC output terminals of the three-phase inverter module are respectively connected to the corresponding power access terminals of the three-phase motor; the power access terminal of the driving module is connected to a first independent power supply. The signal detection terminal of the driving module is connected to the signal output terminal of the Boost-PFC module, and the modulation signal output terminal of the driving module is connected to the modulation signal input terminal of the Boost-PFC module. Compared with the prior art, the circuit of the present invention can stably drive a three-phase motor on the premise of meeting the requirements of heat dissipation and high integration degree.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated circuits, and particularly relates to a circuit for driving a three-phase motor. Background Art

[0002] With the iterative update of household appliances, in order to meet performance requirements such as speed regulation and frequency conversion, the driving motors of electrical appliances such as air conditioner compressors and drum washing machines are gradually adopting three-phase motors. Residential electricity is generally single-phase power supply, and to drive the above three-phase motors, a three-phase power supply method is required for driving. Therefore, after connecting the mains power to the power input end of such high-power electrical appliances, a driving circuit is needed for phase conversion.

[0003] In the prior art, the driving circuit usually consists of a power factor correction module (PFC module), a rectifier bridge module, and a three-phase inverter module. In order to meet the heat dissipation requirements of the driving circuit, it is necessary to perform a discrete design on the power factor correction module, the rectifier bridge module, and the three-phase inverter module, that is, the above three major modules are designed as independent modules of the circuit at intervals, and assembled or welded to the circuit board. The integration level of this driving circuit design scheme is not high, and there are the following defects:

[0004] (1) Due to the discrete setting of the modules, during the actual production of the circuit board, module assembly and welding need to be carried out multiple times, resulting in a relatively high production cost.

[0005] (2) The vibration generated during the operation of the three-phase motor will inevitably affect the driving circuit board itself. The module solder joints or assembly points of the discrete driving circuit are numerous and not concentrated, making it easy for components to become loose. Therefore, such a driving circuit with a low integration level also has stability problems.

[0006] (3) The circuit structure itself is not reasonably designed, and the driving current output from the existing circuit to the three-phase motor is not stable enough, resulting in poor working stability of the three-phase motor.

[0007] Therefore, the prior art has problems of low integration level and poor stability. Summary of the Invention

[0008] The present invention provides a circuit for driving a three-phase motor, which is used to solve the problems of low integration level and poor stability in the prior art.

[0009] In a first aspect, to achieve the above object, the present invention provides a circuit for driving a three-phase motor, including a rectifier bridge module disposed on a circuit board and a Boost (boost)-PFC (Power Factor Correction) module, a driving module, and a three-phase inverter module integrally disposed on the same DBC (Direct Bond Copper) substrate; the DBC substrate is electrically connected to the side of the circuit board by the same pair of pin groups;

[0010] The DBC substrate includes a ceramic substrate and multiple layers of copper foils, and the multiple layers of copper foils are arranged on opposite sides of the ceramic substrate; the multiple layers of copper foils include a power layer, a signal layer, and a ground layer that are connected in sequence; the power layer is in contact with the ceramic substrate, and the ground layer is arranged on one side of the signal layer away from the ceramic substrate; the signal layer includes a first signal layer and a second signal layer, the drive module transmits signals through the first signal layer, and the Boost-PFC module and the three-phase inverter module transmit signals through the second signal layer;

[0011] The AC input terminal of the rectifier bridge module is used to connect to the mains power supply;

[0012] The DC input terminal of the Boost-PFC module is connected to the DC output terminal of the rectifier bridge module;

[0013] The power supply access terminal of the drive module is connected to an external first independent power supply; the signal detection terminal of the drive module is connected to the signal output terminal of the Boost-PFC module; the modulation signal output terminal of the drive module is connected to the modulation signal input terminal of the Boost-PFC module;

[0014] The DC input terminal of the three-phase inverter module is connected to the DC output terminal of the Boost-PFC module, and the three AC output terminals of the three-phase inverter module are respectively connected to the power supply access terminals corresponding to the three-phase motor to be driven.

[0015] Through the above technical solution, the DBC substrate is a direct copper clad ceramic substrate, which has excellent heat dissipation capacity and insulation performance compared with the traditional PCB circuit substrate. In the circuit of the present invention, the Boost-PFC module, the three-phase inverter module, and the drive module are integrated on the same DBC substrate, realizing the high integration of the Boost-PFC module, the three-phase inverter module, and the drive module, changing the traditional single-board flat structure layout, and improving the space utilization rate. In addition, the main structure of the circuit of the present invention is a double-layer board three-dimensional design, which increases the heat dissipation area and further enhances the heat dissipation effect by using the characteristics of the DBC substrate. Therefore, directly integrating the Boost-PFC module, the three-phase inverter module, and the drive module on the DBC substrate can meet the heat dissipation requirements and improve the circuit integration degree. On this basis, the DBC substrate is electrically connected to the side of the circuit substrate by the same pair of pin groups. Each pin group itself has multiple pins spaced from each other, and the DBC substrate is electrically connected to the circuit substrate by two pin groups, that is, multiple dense connection pins are concentrated on the same DBC substrate for soldering or assembly, so that the solder joints or assembly points of the Boost-PFC module, the three-phase inverter module, and the drive module connecting to the circuit substrate are highly concentrated and are not prone to looseness, improving the stability of the drive circuit at the physical structure level. As for the circuit structure, the circuit of the present invention adds a Boost-PFC module to realize DC boost and reduce grid harmonic pollution. The drive module is powered by an independent power supply to achieve "strong-weak isolation". The drive module is used to correct the power factor according to the Boost voltage or current signal and the known mains (current or voltage) signal, and modulate the DC current output by the Boost-PFC module to the three-phase inverter module, improving the stability and reliability of the three-phase motor circuit network. Compared with the prior art, the circuit of the present invention can stably drive a three-phase motor on the premise of meeting the heat dissipation and high integration requirements, and solves the problems of low integration degree and poor stability of the prior art.

[0016] Preferably, it further includes an MCU (Microcontroller Unit) module. The power access terminal of the MCU module is connected to an external second independent power supply. The on-off instruction output terminal of the MCU module is connected to the on-off instruction receiving terminal of the three-phase inverter module. The first signal detection terminal of the MCU module is connected to the feedback signal output terminal of the drive module. The second signal detection terminal of the MCU module is connected to the AC signal output terminal of the three-phase inverter module.

[0017] Through the above technical solution, the circuit of the present invention realizes the monitoring of the drive module and the three-phase inverter module by setting the MCU module. By collecting the feedback signal of the drive module and the AC signal of the three-phase inverter module, the phase and current value of the output current of the three-phase inverter module can be calculated. Based on the phase and current value of the output current and the built-in optimization program, a high-frequency on-off instruction corresponding to the corresponding phase is output to the three-phase inverter module through the on-off instruction output terminal, so that the three-phase inverter module regulates the on-off of the output of the corresponding phase current, improves the current waveform of each phase current, and further improves the stability of the three-phase motor during operation.

[0018] Preferably, the three-phase inverter module includes a forward current output unit and a reverse current output unit;

[0019] The DC output terminals of the Boost-PFC module are respectively connected to the DC input terminals of the forward current output unit and the reverse current output unit;

[0020] The forward current output terminal of the forward current output unit is connected to the power supply access terminal of the three-phase motor to be driven;

[0021] The reverse current output terminal of the reverse current output unit is connected to the power supply access terminal of the three-phase motor to be driven.

[0022] Through the above technical solution, the forward current output unit in the circuit of the present invention is used to output forward current to the three-phase motor, while the reverse current output unit is used to output reverse current to the three-phase motor. The two current output units alternately output current at a high frequency, so that the three-phase motor operates smoothly in the alternating current with a stable waveform.

[0023] Preferably, the forward current output unit includes a first on-off control sub-unit and three first switch sub-units;

[0024] The power supply access terminal of the first on-off control sub-unit is connected to an external first independent power supply;

[0025] The DC input terminal of the first switch sub-unit is connected to the DC output terminal of the Boost-PFC module. The switch control terminal of the first switch sub-unit is connected to the corresponding on-off control terminal of the first on-off control sub-unit. The forward current output terminal of the first switch sub-unit is connected to the corresponding power supply access terminal of the three-phase motor to be driven.

[0026] Through the above technical solution, the first on-off control subunit is powered by a first independent power supply to achieve "strong-weak isolation". The first switch subunit is controlled by the first on-off control subunit. When the first on-off control subunit outputs a conduction signal, the first switch subunit conducts, and the current of the corresponding phase is output to the three-phase motor. When the first on-off control subunit outputs a turn-off signal, the first switch subunit turns off, and the current of the corresponding phase is cut off. Compared with the prior art, the circuit of this method can flexibly adjust the forward current of each phase input to the three-phase motor, which is beneficial to the frequency conversion and speed regulation of the three-phase motor.

[0027] Preferably, the first switch subunit includes a first switching element and a first freewheeling diode;

[0028] The DC input terminal of the first switching element is connected to the DC output terminal of the Boost-PFC module, the switching control terminal of the first switching element is connected to the corresponding on-off control terminal of the first on-off control subunit, and the forward current output terminal of the first switching element is connected to the corresponding power access terminal of the three-phase motor;

[0029] The anode of the first freewheeling diode is connected to the forward current output terminal of the first switching element, and the cathode of the first freewheeling diode is connected to the DC input terminal of the first switching element.

[0030] Through the above technical solution, the first switch subunit is composed of a first switching element and a first freewheeling diode. A first freewheeling diode is connected in parallel between the forward current output terminal and the DC input terminal of the first switching element, which is beneficial to providing a current freewheeling channel when the first switching element is turned off, ensuring that the current will not suddenly interrupt, protecting the first switching element, and the first freewheeling diode can also play a role in smoothing the current fluctuation and reducing the impact of current mutation on the circuit.

[0031] Preferably, the reverse current output unit includes a second on-off control subunit and three second switch subunits;

[0032] The power access terminal of the second on-off control subunit is connected to an external second independent power supply;

[0033] The DC input terminal of the second switch subunit is connected to the DC output terminal of the Boost-PFC module, the switching control terminal of the second switch subunit is connected to the corresponding on-off control terminal of the second on-off control subunit, and the reverse current output terminal of the second switch subunit is connected to the corresponding power access terminal of the three-phase motor to be driven.

[0034] Preferably, the second switch subunit includes a second switching element and a second freewheeling diode;

[0035] The DC input terminal of the second switching element is connected to the DC output terminal of the Boost-PFC module, the switching control terminal of the second switching element is connected to the corresponding on / off control terminal of the second on / off control sub-unit, and the reverse current output terminal of the second switching element is connected to the corresponding power supply access terminal of the three-phase motor;

[0036] The anode of the second freewheeling diode is connected to the reverse current output terminal of the second switching element, and the cathode of the second freewheeling diode is connected to the DC input terminal of the second switching element.

[0037] Preferably, the Boost-PFC module includes a switching element Q1, a PFC diode D1, and a snubber diode D2;

[0038] The gate of the switching element Q1 serves as the modulation signal input terminal, the emitter of the switching element Q1 serves as the signal output terminal, and the collector of the switching element Q1 is connected to the DC output terminal of the rectifier bridge module;

[0039] The anode of the PFC diode D1 is connected to the collector of the switching element Q1, and the cathode of the PFC diode D1 serves as the DC output terminal of the Boost-PFC module;

[0040] The anode of the snubber diode D2 is connected to the emitter of the switching element Q1, and the cathode of the snubber diode D2 is connected to the collector of the switching element Q1.

[0041] Through the above technical solution, the switching element Q1, as the core switching device of the Boost-PFC module, is regulated by the drive module and can be switched on and off at high frequency according to the modulation signal. The PFC diode, as a current rectifier, can improve the power factor of the power supply. The snubber diode D2, also known as a TVS diode, as a circuit protection element, its main function is to absorb and suppress voltage spikes in the circuit and play a role in protecting the switching element Q1.

[0042] Preferably, the switching element Q1 is any one of MOSFET, IGBT, or BJT.

[0043] Preferably, the rectifier bridge module adopts a full-bridge rectifier module.

[0044] Through the above technical solution, the full-bridge rectifier circuit can rectify both the positive and negative half-cycles of the mains electricity, thereby obtaining a smoother DC output.

[0045] In a second aspect, to achieve the above object, the present invention also provides a method for driving a three-phase motor, which is implemented by using the above circuit for driving a three-phase motor. The method of the present invention includes:

[0046] Obtain a first signal output from the signal output terminal of the Boost-PFC module;

[0047] According to a preset mains power signal and a first signal, correct the power factor and input a modulation signal to the modulation signal input terminal of the Boost-PFC module;

[0048] According to the modulation signal, adjust the duty cycle of the output of the Boost-PFC module to obtain a first direct current;

[0049] Adopt a three-phase inverter module to shunt and invert the first direct current and output a three-phase alternating current to the three-phase motor.

[0050] Preferably, the first signal includes the output voltage and output current of the Boost-PFC module; according to the preset mains power signal and the first signal, correcting the power factor and inputting a modulation signal to the modulation signal input terminal of the Boost-PFC module includes:

[0051] Calculate the current power factor according to the preset mains power signal, the output voltage of the Boost-PFC module and the output current of the Boost-PFC module;

[0052] Judge whether the current power factor is greater than the target power factor. If so, maintain the current power factor and input a modulation signal to the modulation signal input terminal of the Boost-PFC module; if not, increase the current power factor until the current power factor is greater than the target power factor, and input a modulation signal to the modulation signal input terminal of the Boost-PFC module.

[0053] The present invention has at least the following advantages:

[0054] 1) The circuit of the present invention integrates the Boost-PFC module, the three-phase inverter module and the drive module on the same DBC substrate to meet the heat dissipation requirements. On this basis, the DBC substrate is electrically connected to the side of the circuit substrate by the same pair of pin groups, so that the welding points or assembly points of the Boost-PFC module, the three-phase inverter module and the drive module connecting to the circuit substrate are highly concentrated and are not likely to become loose, improving the stability of the drive circuit at the physical structure level. As for the circuit structure, the circuit of the present invention adds a Boost-PFC module to realize DC boost and reduce grid harmonic pollution. The drive module is powered by an independent power supply to achieve "strong-weak isolation". The drive module is used to correct the power factor and negatively feedback and regulate the direct current output by the Boost-PFC module to the three-phase inverter module, so that the value of the direct current output by the Boost-PFC module to the three-phase inverter module is maintained within a predetermined range, improving the stability and reliability of the three-phase motor circuit network. Compared with the prior art, the circuit of the present invention can stably drive a three-phase motor on the premise of meeting the heat dissipation and high integration requirements. Moreover, the DBC substrate of the present application has strong electromagnetic shielding ability and can achieve high-quality signal transmission.

[0055] 2) By setting up the MCU module in the circuit of the present invention, the monitoring of the drive module and the three-phase inverter module can be realized. By collecting the feedback signal of the drive module and the AC signal of the three-phase inverter module, the phase and current value of the output current of each phase of the three-phase inverter module can be calculated. And based on the phase and current value of the output current of each phase, through the built-in optimization program, a high-frequency on-off instruction corresponding to the phase is output to the three-phase inverter module through the on-off instruction output terminal, so that the three-phase inverter module regulates the on-off of the output of the corresponding phase current, improves the current waveform of each phase current, and further improves the stability of the three-phase motor during operation.

[0056] 3) The method of the present invention first obtains the first signal output from the signal output terminal of the Boost-PFC module, then corrects the power factor according to the preset mains signal and the first signal and inputs a modulation signal to the modulation signal input terminal of the Boost-PFC module. Then, according to the modulation signal, the duty cycle output by the Boost-PFC module is adjusted to obtain a smooth and stable first DC current. Finally, the three-phase inverter module is used to shunt and invert the first DC current to output a stable and smooth three-phase AC current to the three-phase motor, thereby improving the stability of the three-phase motor during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0058] Figure 1 It is a schematic diagram of the circuit for driving a three-phase motor in Embodiment 1 of the present invention;

[0059] Figure 2 It is a schematic diagram of the structure of the circuit for driving a three-phase motor in Embodiment 1 of the present invention arranged on the DBC substrate and the circuit substrate;

[0060] Figure 3 It is a schematic diagram of the structure of the DBC substrate provided in the embodiment of the present invention;

[0061] Figure 4 It is a schematic diagram of the circuit for driving a three-phase motor in Embodiment 2 of the present invention;

[0062] Figure 5 It is a schematic circuit diagram of the circuit for driving a three-phase motor in Embodiment 3 of the present invention;

[0063] Figure 6 It is a schematic circuit diagram of the Boost-PFC module and the three-phase inverter module in Embodiment 3 of the present invention;

[0064] Figure 7 This is the layout diagram of the DBC substrate electronic components for the circuit used to drive a three-phase motor in the fourth embodiment of the present invention;

[0065] Figure 8 This is the flowchart of the method for driving a three-phase motor in the fifth embodiment of the present invention.

[0066] Reference numerals:

[0067] 100, circuit board; 200, DBC substrate; 210, ceramic substrate; 220, power layer; 230, first signal layer; 240, second signal layer; 250, ground layer; 201, pin group; 300, three-phase motor; 1, rectifier bridge module; 2, Boost-PFC module; 3, drive module; 4, three-phase inverter module; 41, forward current output unit; 42, reverse current output unit; 5, MCU module. Detailed implementation manners

[0068] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation manners, structures, features, and their effects of the present invention as follows.

[0069] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0070] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0071] This embodiment discloses a circuit for driving a three-phase motor, which is used to stably drive the three-phase motor on the premise of meeting the requirements of heat dissipation and high integration.

[0072] Embodiment 1

[0073] As Figure 1 shown, this embodiment discloses a circuit for driving a three-phase motor, which includes a rectifier bridge module 1, a Boost-PFC module 2, a drive module 3, and a three-phase inverter module 4.

[0074] Among them, the AC input terminal of the rectifier bridge module 1 is connected to the mains power supply, which is used to convert the AC 220V of the mains power supply into DC 220V for output. The Boost-PFC module 2 is used for boosting and reducing grid harmonic pollution. Its DC input terminal is connected to the DC output terminal of the rectifier bridge module 1, and is used to boost the DC 220V to a predetermined voltage. The DC input terminal of the three-phase inverter module 4 is connected to the DC output terminal of the Boost-PFC module 2, and its three AC output terminals are respectively connected to the corresponding power access terminals of the three-phase motor 300. The three-phase inverter module 4 is used to receive the output current of the Boost-PFC module 2 and convert the direct current into three-phase alternating current through inversion to supply the three-phase motor 300.

[0075] On the basis of the above circuit design, the power access terminal of the drive module 3 is connected to an external first independent power supply (+15V) to achieve "strong-weak isolation" and avoid damage to the drive module 3 by strong electricity. The signal detection terminal of the drive module 3 is connected to the signal output terminal of the Boost-PFC module 2 to obtain the voltage or current signal of the Boost-PFC module 2. The modulation signal output terminal of the drive module 3 is connected to the modulation signal input terminal of the Boost-PFC module 2 to correct the power factor according to the voltage or current signal of the Boost-PFC module 2 and the mains power signal, and modulate the DC current output by the Boost-PFC module 2 to the three-phase inverter module 4 according to the power factor until the DC current value and DC waveform output by the Boost-PFC module 2 to the three-phase inverter module 4 are maintained within a predetermined range to improve the stability and reliability of the three-phase motor 300 circuit network.

[0076] Further, as Figure 2 shown, in order to meet the requirements of heat dissipation and structural stability, the above rectifier bridge module 1 is arranged on the circuit board 100, while the Boost-PFC module 2, the drive module 3 and the three-phase inverter module 4 are integrally arranged in the same DBC board 200. The DBC board 200 is electrically connected to the side surface of the circuit board 100 by the same pair of pin groups 201.

[0077] Through the above structural improvement, as a direct copper clad ceramic substrate, the DBC substrate 200 has excellent heat dissipation capacity and insulation performance compared with the traditional PCB circuit substrate 100. In this invention, the Boost-PFC module 2, the three-phase inverter module 4, and the drive module 3 are integrated on the same specially designed DBC substrate 200 adapted to the above three modules, achieving a high degree of integration of the Boost-PFC module 2, the three-phase inverter module 4, and the drive module 3, changing the traditional single-board flat layout structure, and realizing a high degree of integration of the three modules by using the specially designed DBC substrate 200, improving the space utilization rate. In addition, the main structure of the circuit of this invention is a double-layer board three-dimensional design, increasing the heat dissipation area, and further enhancing the heat dissipation effect by using the characteristics of the DBC substrate 200. Therefore, directly integrating the Boost-PFC module 2, the three-phase inverter module 4, and the drive module 3 on the DBC substrate 200 can meet the heat dissipation requirements and improve the circuit integration degree. The DBC substrate 200 is electrically connected to the side of the circuit substrate 100 by the same pair of pin groups 201, making the solder joints or assembly points of the Boost-PFC module 2, the three-phase inverter module 4, and the drive module 3 connected to the circuit substrate 100 highly concentrated, not easily loosening, and improving the stability of the drive circuit at the physical structure level.

[0078] Different from the conventional DBC substrate, the above specially designed DBC substrate 200 is realized by a nitrogen baking process flow, and the specially designed DBC substrate 200 is based on the highly integrated design of the Boost-PFC module 2, the three-phase inverter module 4, and the drive module 3.

[0079] See Figure 3 , more specifically, the DBC substrate 200 includes a ceramic substrate and multiple layers of copper foil, and the multiple layers of copper foil are arranged on opposite sides of the ceramic substrate; the multiple layers of copper foil include a power layer, a signal layer, and a ground layer connected in sequence; the power layer is in contact with the ceramic substrate, and the ground layer is arranged on the side of the signal layer away from the ceramic substrate; the signal layer includes a first signal layer and a second signal layer, the drive module transmits signals through the first signal layer, and the Boost-PFC module and the three-phase inverter module transmit signals through the second signal layer.

[0080] Specifically, this application also makes changes to the DBC substrate 200. The DBC substrate 200 is provided with a ceramic substrate 210 and multiple layers of copper foil. The power layer 220, the signal layer, and the ground layer 250 are formed by the multiple layers of copper foil, and the ground layer 250 is arranged on the side of the signal layer away from the ceramic substrate 210, which can improve the electromagnetic shielding ability and heat dissipation ability of the DBC substrate 200. The signal layer is mainly used to transmit control signals and feedback signals, such as the control signals of the drive module, the status feedback signals of the power module, etc.

[0081] The copper foil thickness of the grounding layer 250 can be designed according to actual needs. More preferably, the signal layers of the present application include a first signal layer 230 and a second signal layer 240. By arranging different signal layers, high-speed signals (high-frequency drive signals of the drive module) and power signals (such as large-current lines of the Boost-PFC module and the three-phase inverter module) are arranged in layers, reducing the electromagnetic coupling between them. In addition, the grounding layer 250 is placed on one side adjacent to the signal layer as the return path of the signal to reduce the loop area and electromagnetic radiation.

[0082] More preferably, a dielectric layer is further provided between the copper foils of each layer. The dielectric layer is made of an insulating material such as polyimide (PI) or epoxy resin. More preferably, the dielectric layer is polyimide. Polyimide has good insulation properties, mechanical properties and thermal stability, can withstand higher temperatures, and at the same time has a low dielectric constant, which can reduce the delay and loss of signal transmission and is suitable for high-frequency signal transmission areas. In a more preferred embodiment, an electromagnetic shielding material such as nano-metal particles or magnetic materials is added to the dielectric layer. The electromagnetic shielding material is used to enhance the shielding ability of the dielectric layer to electromagnetic signals. These additives are used to absorb or reflect electromagnetic signals and prevent them from propagating in the dielectric layer, thereby reducing electromagnetic coupling. And, the surface of the dielectric layer is coated with a coating to reduce the surface roughness of the dielectric layer, thereby reducing the scattering and reflection of electromagnetic signals on the surface of the dielectric layer and further reducing electromagnetic coupling. In addition, grooves are provided in the dielectric layer, and the signal layer is embedded in the grooves. The grooves completely cover the edges of the signal layer, thereby reducing the leakage of electromagnetic signals to the outside and the coupling with other layers.

[0083] Specifically, the specific production process flow of the above-mentioned special DBC substrate 200 is as follows:

[0084] Incoming material inspection -> Warehousing -> Loading -> Printing -> Solder paste die bonding -> Electronic component assembly -> Vacuum reflow component soldering -> Reflow soldering appearance inspection -> Ultrasonic cleaning -> Silver paste die bonding -> Baking -> AL wire soldering -> Plasma cleaning -> Palladium-plated copper wire / gold wire soldering -> Gate inspection -> Encapsulation -> Curing -> Electroplating -> Electroplating appearance inspection -> Electroplating baking -> Trimming and forming -> Withstand voltage test -> Normal temperature test -> Laser marking -> FQA electrical test -> Appearance inspection -> FQA inspection -> Finished product packaging.

[0085] Different from the prior art, the above-specified DBC substrate 200 completes solder joint welding by means of vacuum reflow, making the heating of each pad on the highly integrated printed circuit board of the DBC substrate 200 uniform, thereby making it possible to weld each dense solder joint of the above-mentioned several major modules. On this basis, the DBC substrate 200 also uses ultrasonic technology to clean the solder joint impurities, avoiding short circuits caused by the bridging of conductive impurities in the densely distributed solder joints. After ultrasonic cleaning, the silver glue die bonding method is used to enhance the heat dissipation effect and the adhesion ability of electronic components.

[0086] Compared with the prior art, the circuit of the present invention can stably drive the three-phase motor 300 on the premise of meeting the requirements of heat dissipation and high integration.

[0087] More specifically, the present application also provides the detailed manufacturing process of the DBC substrate 200:

[0088] Select a suitable ceramic substrate 210 according to the application requirements, and use methods such as chemical cleaning or physical polishing to treat the surface of the ceramic substrate 210 to remove surface impurities and contaminants, ensuring the surface flatness and cleanliness of the ceramic substrate 210.

[0089] Select copper foil: For the power layer 220, select a relatively thick copper foil with a thickness of 200 - 500 μm or even thicker to meet the requirements of large current transmission. For the signal layers (including the first signal layer 230 and the second signal layer 240), select a relatively thin copper foil, usually with a thickness of about 35 - 70 μm, to reduce signal transmission loss and electromagnetic interference. For the ground layer 250, select a copper foil with an appropriate thickness according to the required grounding performance and heat dissipation performance, and its thickness can be adjusted according to specific design requirements. In addition, the copper foil needs to be cleaned to remove surface oil, oxides and other impurities. Chemical cleaning agents or physical cleaning methods such as ultrasonic cleaning can be used to ensure the cleanliness of the copper foil surface. The copper foil surface is roughened, for example, by chemical etching or mechanical polishing, etc., to increase the roughness of the copper foil surface, which helps to improve the bonding strength between the copper foil and the ceramic substrate 210.

[0090] Place the treated copper foil on the ceramic substrate 210 and heat it in a high-temperature furnace to about 1065 °C. At this temperature, the copper atoms in the copper foil react with the oxygen atoms on the ceramic surface to form compounds such as CuAlO2, realizing the firm bonding of the copper foil and the ceramic substrate 210. Precisely control the temperature, time and atmosphere during the bonding process to ensure the quality and consistency of the bonding. The heating process needs to be heated up slowly to avoid stress generation between the copper foil and the ceramic substrate 210 due to too rapid temperature change, which affects the bonding strength.

[0091] Use photolithography technology to transfer the designed circuit pattern of the power layer 220 onto the copper foil.

[0092] For the first signal layer 230 and the second signal layer 240, the photolithography and etching processes are also adopted.

[0093] First, a photoresist is coated on the copper foil. The circuit pattern of the signal layer required, such as the high-frequency drive signal of the drive module and the status feedback signal of the power module, is exposed through a mask plate, and then developed to expose the copper foil part to be retained. Then, the etching process is used to remove the redundant copper foil to form the circuit pattern of the first signal layer 230. Then, based on the first signal layer 230, the copper layer of the second signal layer 240 is electroplated, and the circuit pattern is formed on the second signal layer 240 using the exposure, development, and etching processes. Then, according to the design requirements, the control signal of the drive module is arranged on the first signal layer 230, and the relevant signals of the large-current lines of the Boost-PFC module and the three-phase inverter module are arranged on the second signal layer 240 to achieve the hierarchical arrangement of high-speed signals and power signals and reduce electromagnetic coupling.

[0094] The copper foil circuit pattern of the ground layer 250 is fabricated and arranged on the side of the signal layer away from the ceramic substrate 210. The copper foil of the ground layer 250 also forms the required grounding network through the photolithography and etching processes, providing a stable reference potential for the entire circuit and serving as the return path of the signal to reduce the loop area and lower electromagnetic radiation.

[0095] It should be noted that between the fabrications of different copper foil layers, a coating process is also used to uniformly coat the liquid polyimide on the formed copper foil layer, and then a curing treatment is performed to make it form a solid dielectric layer.

[0096] The circuit principle of this embodiment is as follows:

[0097] The commercial power current of AC 220V is rectified by the rectifier bridge module 1 to obtain a DC current and flows into the Boost-PFC module 2. During this period, the drive module 3 calculates the power factor of the boost of the Boost-PFC module 2, corrects the power factor, and adjusts the output current of the Boost-PFC module 2 to make the output current value of the Boost-PFC module 2 reach a predetermined range. Then, the three-phase inverter module 4 converts the output current of the Boost-PFC module 2 into a three-phase AC current and outputs it to the three-phase motor 300.

[0098] Embodiment 2

[0099] As Figure 5 shown, based on Embodiment 1, the circuit for driving a three-phase motor disclosed in this embodiment further includes an MCU module 5.

[0100] Among them, the power supply input terminal of the MCU module 5 is connected to an external second independent power supply (+5V) to achieve "strong-weak isolation", enabling the MCU module 5 to operate in a stable power supply environment. The first signal detection terminal of the MCU module 5 is connected to the feedback signal output terminal of the drive module 3, and the second signal detection terminal of the MCU module 5 is connected to the AC signal output terminal of the three-phase inverter module 4 to monitor the drive module 3 and the three-phase inverter module 4. The on-off instruction output terminal of the MCU module 5 is connected to the on-off instruction receiving terminal of the three-phase inverter module 4 to achieve the regulation of the three-phase inverter module 4 by the MCU module 5.

[0101] In this embodiment, the chip model of the MCU module 5 can adopt the IMC302A series of chips, which is an intelligent power regulation chip that can meet the output power regulation, frequency modulation, and speed regulation requirements of the three-phase motor 300.

[0102] Through the above circuit design, the MCU module 5 collects the feedback signal of the drive module 3 and the AC signal of the three-phase inverter module 4, can calculate the phase and current value of the output current of each phase of the three-phase inverter module 4, and based on the phase and current value of the output current of each phase, through the built-in optimization program, outputs the high-frequency on-off instruction of the corresponding phase to the three-phase inverter module 4 through the on-off instruction output terminal, enabling the three-phase inverter module 4 to regulate the on-off of the output of the corresponding phase current, thereby improving the current waveform of each phase current, and further improving the stability of the three-phase motor 300 during operation.

[0103] Embodiment Three

[0104] As Figure 5 shown, on the basis of Embodiment Two, this embodiment discloses a circuit for driving a three-phase motor. Its rectifier bridge module 1 adopts a full-bridge rectifier module, and rectifies both the positive and negative half-cycles of the commercial power through full-bridge rectification, which can make the current output by the rectifier bridge module 1 smoother, is beneficial to reducing the impact when the three-phase motor 300 starts or stops, and improves the running stability of the three-phase motor 300.

[0105] In order to further improve the power factor of the power supply of the three-phase motor 300, in this embodiment, the Boost-PFC module 2 includes a switching element Q1, a PFC diode D1, and a snubber diode D2.

[0106] Among them, as Figure 5As shown, the gate of the switching element Q1 serves as the modulation signal input terminal, the emitter of the switching element Q1 serves as the signal output terminal, and the collector of the switching element Q1 is connected to the DC output terminal of the rectifier bridge module 1. The positive electrode of the PFC diode D1 is connected to the collector of the switching element Q1, and the negative electrode of the PFC diode D1 serves as the DC output terminal of the Boost-PFC module 2. The positive electrode of the absorption diode D2 is connected to the emitter of the switching element Q1, and the negative electrode of the absorption diode D2 is connected to the collector of the switching element Q1.

[0107] It should be added that the Boost-PFC module 2 is also provided with large-capacitance filtering on the periphery. One end of the large capacitor is connected to the emitter of the switching element Q1, and the other end is connected to the negative electrode of the PFC diode D1 to improve the stability of the output current.

[0108] Through the above circuit design, the switching element Q1 is regulated by the drive module 3 and can be switched on and off at high frequency according to the modulation signal. The PFC diode, as a current rectifier, can improve the power factor of the power supply. As for the absorption diode D2, as a circuit protection element, its main function is to absorb and suppress voltage spikes in the circuit and play a role in protecting the switching element Q1.

[0109] Preferably, the switching element Q1 can be any one of MOSFET, IGBT or BJT. Among them, the IGBT has the best performance and can meet the daily needs of household appliances. For some electrical appliances with low requirements for switching frequency or low power, using MOSFET as the switching element Q1 can reduce production costs.

[0110] In this embodiment, in order to supply stable alternating current to the three-phase motor 300, the circuit of the present invention is implemented by alternately outputting the current direction at a high frequency.

[0111] Specifically, the three-phase inverter module 4 includes a forward current output unit 41 and a reverse current output unit 42. The DC output terminal of the Boost-PFC module 2 is respectively connected to the DC input terminals of the forward current output unit 41 and the reverse current output unit 42. The forward current output terminal of the forward current output unit 41 is connected to the power supply access terminal of the three-phase motor 300. The reverse current output terminal of the reverse current output unit 42 is connected to the power supply access terminal of the three-phase motor 300.

[0112] More specifically, the forward current output unit 41 includes a first on-off control sub-unit and three first switching sub-units. The power supply access terminal of the first on-off control sub-unit is connected to the first independent power supply (+15V) to achieve "strong-weak isolation".

[0113] The DC input terminal of the first switching sub-unit is connected to the DC output terminal of the Boost-PFC module 2. The switching control terminal of the first switching sub-unit is connected to the corresponding on-off control terminal of the first on-off control sub-unit. The forward current output terminal of the first switching sub-unit is connected to the corresponding power access terminal of the three-phase motor 300.

[0114] In this embodiment, the first on-off control sub-unit is Figure 4 the shown driving chip U1, and the first switching sub-unit includes IGBT tubes Q1, Q2 and Q3. The driving chip U1 is provided with input pins connected to the MCU module 5 to receive the instructions output by the MCU module 5. The output pins of the driving chip U1, as the on-off control terminals of the first on-off control sub-unit, are respectively connected to the bases of the IGBT tubes Q1, Q2 and Q3 to control the conduction and cut-off of the IGBT tubes Q1, Q2 and Q3.

[0115] Furthermore, the first switching sub-unit includes a first switching element and a first freewheeling diode. In this embodiment, the first switching sub-unit generally refers to the IGBT tubes Q1, Q2 and Q3, and the first freewheeling diodes generally refer to the freewheeling diodes D3, D4 and D5. The DC input terminal of the first switching element is connected to the DC output terminal of the Boost-PFC module 2. The switching control terminal of the first switching element is connected to the corresponding on-off control terminal of the first on-off control sub-unit. The forward current output terminal of the first switching element is connected to the corresponding power access terminal of the three-phase motor 300. The positive pole of the first freewheeling diode is connected to the forward current output terminal of the first switching element, and the negative pole of the first freewheeling diode is connected to the DC input terminal of the first switching element.

[0116] By connecting the first freewheeling diode in parallel between the forward current output terminal and the DC input terminal of the first switching element, it is beneficial to provide a current freewheeling channel when the first switching element is turned off, ensuring that the current will not suddenly interrupt, protecting the first switching element, and the first freewheeling diode can also play a role in smoothing the current fluctuation and reducing the impact of current mutation on the circuit.

[0117] Similar to the circuit design structure of the above-mentioned forward current output unit 41, in this embodiment, the reverse current output unit 42 includes a second on-off control sub-unit and three second switching sub-units. The power access terminal of the second on-off control sub-unit is connected to the second independent power supply (+5V). The DC input terminal of the second switching sub-unit is connected to the DC output terminal of the Boost-PFC module 2. The switching control terminal of the second switching sub-unit is connected to the corresponding on-off control terminal of the second on-off control sub-unit. The reverse current output terminal of the second switching sub-unit is connected to the corresponding power access terminal of the three-phase motor 300.

[0118] Different from the forward current output unit 41, in this embodiment, the second on-off control sub-unit is Figure 4the driving chip U2 therein, and the second switching elements of the second switching subunit generally refer to the IGBT tubes Q5, Q6, and Q7.

[0119] More specifically, the second switching subunit includes a second switching element and a second freewheeling diode. The DC input terminal of the second switching element is connected to the DC output terminal of the Boost-PFC module 2, the switching control terminal of the second switching element is connected to the corresponding on-off control terminal of the second on-off control subunit, and the reverse current output terminal of the second switching element is connected to the corresponding power access terminal of the three-phase motor 300. The positive pole of the second freewheeling diode is connected to the reverse current output terminal of the second switching element, and the negative pole of the second freewheeling diode is connected to the DC input terminal of the second switching element.

[0120] In this embodiment, during the process of the forward current output unit 41 outputting a forward current, the three second switching subunits are always in the off state.

[0121] Compared with the prior art, this embodiment makes specific improvements to the Boost-PFC module 2 and the three-phase inverter module 4, and uses full-bridge rectification technology for rectification, so that the three-phase current output by the circuit of the present invention has excellent smoothness, which is beneficial to the smooth operation of the three-phase motor.

[0122] Embodiment Four

[0123] Based on Embodiment Three, in this embodiment, the above-mentioned IGBTs and diodes are all integrally arranged on the DBC substrate 200, and a pair of pin groups 201 for connecting the circuit substrate 100 are arranged on both sides of the DBC substrate 200.

[0124] As Figure 7 shown, this embodiment optimizes the process layout of 17 chips (IGBTs, diodes, driving chip U1, and driving chip U2) on the DBC substrate 200.

[0125] Specifically, a stencil for 17 chips is opened on the DBC substrate 200, which is realized by using the nitrogen baking process described in CN116741764 A, so that the layout of these chips is more compact, stable and conducive to pipeline production.

[0126] Preferably, the driving module 3 chip of this embodiment can adopt the bridge-less PFC control chip described in CN116741764 A.

[0127] Compared with the prior art, this embodiment ensures that the positions of the chips will not drift by increasing the stencil opening rate and compact design, thereby further improving the physical structure stability of the circuit of the present invention.

[0128] Embodiment Five

[0129] As Figure 8As shown, this embodiment provides a method for driving a three-phase motor, which is implemented by using the circuit for driving a three-phase motor described in the above embodiment. The method of the present invention includes:

[0130] S10: Obtain a first signal output from the signal output terminal of the Boost-PFC module.

[0131] It should be noted that the above first signal can be the boosted voltage signal of the Boost-PFC module or a current signal.

[0132] S20: Correct the power factor according to the preset mains signal and the first signal, and input a modulation signal to the modulation signal input terminal of the Boost-PFC module.

[0133] It should be noted that the mains signal is AC 220V / 50Hz. Generally, such a signal is a known signal.

[0134] S30: Adjust the duty cycle output by the Boost-PFC module according to the modulation signal to obtain a first DC current.

[0135] S40: Use a three-phase inverter module to shunt and invert the first DC current, and output a three-phase AC current to the three-phase motor.

[0136] Further, the above S20 is specifically:

[0137] Correcting the power factor according to the preset mains signal and the first signal and inputting a modulation signal to the modulation signal input terminal of the Boost-PFC module includes:

[0138] Calculate the current power factor according to the preset mains signal, the output voltage of the Boost-PFC module, and the output current of the Boost-PFC module;

[0139] Judge whether the current power factor is greater than the target power factor. If so, maintain the current power factor and input a modulation signal to the modulation signal input terminal of the Boost-PFC module; if not, increase the current power factor until the current power factor is greater than the target power factor, and input a modulation signal to the modulation signal input terminal of the Boost-PFC module;

[0140] The first signal includes the output voltage of the Boost-PFC module and the output current of the Boost-PFC module.

[0141] Specifically, the calculation algorithm of the above current power factor is:

[0142] ;

[0143] Wherein, is the output voltage of the Boost-PFC module, is the output current of the Boost-PFC module, is the mains voltage, is the mains current.

[0144] If is less than the target power factor, then by modulating the duty cycle of the output current of the Boost-PFC module 2, increase to improve until it is greater than the target power factor.

[0145] Compared with the prior art, the method of the present invention first obtains a first signal output from the signal output end of the Boost-PFC module, then corrects the power factor according to the preset mains signal and the first signal and inputs a modulation signal to the modulation signal input end of the Boost-PFC module, and then adjusts the duty cycle output by the Boost-PFC module according to the modulation signal to obtain a smooth and stable first DC current. Finally, a three-phase inverter module is used to shunt and invert the first DC current to output a stable and smooth three-phase AC current to the three-phase motor, thereby improving the stability of the operation of the three-phase motor.

[0146] Those of ordinary skill in the art can understand that all or part of the steps of implementing the above embodiments can be completed by hardware related to program instructions. The foregoing program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps including the above method embodiments; and the foregoing storage medium includes: various media such as ROM, RAM, magnetic disk, or optical disk that can store program codes.

[0147] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the equivalent embodiments by using the above-disclosed technical content without departing from the technical solution of the present invention. However, any brief modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A circuit for driving a three-phase motor, characterized in that: It comprises a rectifier bridge module (1) arranged on a circuit substrate (100) and a Boost-PFC module (2), a drive module (3) and a three-phase inverter module (4) which are integrated and arranged on the same DBC substrate (200); the DBC substrate (200) is electrically connected to the side surface of the circuit substrate (100) using the same pair of pin groups (201); The DBC substrate (200) comprises a ceramic substrate (210) and a multi-layer copper foil, wherein the multi-layer copper foil is arranged on two opposite sides of the ceramic substrate (210); the multi-layer copper foil comprises a power layer (220), a signal layer and a ground layer (250) which are connected in sequence; the power layer (220) is connected to the ceramic substrate (210), and the ground layer (250) is arranged on a side of the signal layer away from the ceramic substrate (210); the signal layer comprises a first signal layer (230) and a second signal layer (240), the drive module performs signal transmission through the first signal layer (230), and the Boost-PFC module and the three-phase inverter module perform signal transmission through the second signal layer (240); The AC input end of the rectifier bridge module (1) is used to connect to the mains; The DC input end of the Boost-PFC module (2) is connected to the DC output end of the rectifier bridge module (1); The power supply input end of the driving module (3) is connected to an external first independent power supply; the signal detection end of the driving module (3) is connected to the signal output end of the Boost-PFC module (2); and the modulation signal output end of the driving module (3) is connected to the modulation signal input end of the Boost-PFC module (2); The DC input end of the three-phase inverter module (4) is connected to the DC output end of the Boost-PFC module (2), and the three AC output ends of the three-phase inverter module (4) are respectively connected to the power supply access ends corresponding to the three-phase motor (300) to be driven; the three-phase inverter module (4) comprises a forward current output unit (41) and a reverse current output unit (42); The DC output end of the Boost-PFC module (2) is respectively connected to the DC input ends of the forward current output unit (41) and the reverse current output unit (42); The forward current output end of the forward current output unit (41) is connected to a power supply input end of a three-phase motor (300) to be driven; The reverse current output end of the reverse current output unit (42) is connected to a power supply access end of a three-phase motor (300) to be driven; The forward current output unit (41) comprises a first on-off control subunit and three first switch subunits; The power supply access terminal of the first on-off control subunit is connected to an external first independent power supply; The DC input end of the first switch subunit is connected to the DC output end of the Boost-PFC module (2), the switch controlled end of the first switch subunit is connected to the on-off control end corresponding to the first on-off control subunit, and the forward current output end of the first switch subunit is connected to the power supply access end corresponding to the three-phase motor (300) to be driven.

2. The circuit for driving a three-phase motor according to claim 1, characterized in that: It also comprises an MCU module (5), wherein a power supply input terminal of the MCU module (5) is connected to an external second independent power supply, an on / off instruction output terminal of the MCU module (5) is connected to an on / off instruction receiving terminal of the three-phase inverter module (4), a first signal detection terminal of the MCU module (5) is connected to a feedback signal output terminal of the drive module (3), and a second signal detection terminal of the MCU module (5) is connected to an AC signal output terminal of the three-phase inverter module (4).

3. The circuit for driving a three-phase motor according to claim 1, characterized in that: The first switch subunit includes a first switch element and a first freewheeling diode; The DC input end of the first switch element is connected to the DC output end of the Boost-PFC module (2), the switch controlled end of the first switch element is connected to the on-off control end corresponding to the first on-off control subunit, and the forward current output end of the first switch element is connected to the power supply access end corresponding to the three-phase motor (300); The anode of the first freewheeling diode is connected to the forward current output terminal of the first switching element, and the cathode of the first freewheeling diode is connected to the DC input terminal of the first switching element.

4. The circuit for driving a three-phase motor according to claim 1, characterized in that: The reverse current output unit (42) comprises a second on-off control subunit and three second switch subunits; The power supply access terminal of the second on-off control subunit is connected to an external second independent power supply; The DC input end of the second switch subunit is connected to the DC output end of the Boost-PFC module (2), the switch controlled end of the second switch subunit is connected to the corresponding on / off control end of the second on / off control subunit, and the reverse current output end of the second switch subunit is connected to the corresponding power supply access end of the three-phase motor (300) to be driven.

5. The circuit for driving a three-phase motor according to claim 4, characterized in that: The second switch subunit includes a second switch element and a second freewheeling diode; The DC input end of the second switch element is connected to the DC output end of the Boost-PFC module (2), the switch controlled end of the second switch element is connected to the on-off control end corresponding to the second on-off control subunit, and the reverse current output end of the second switch element is connected to the power supply access end corresponding to the three-phase motor (300); The anode of the second freewheeling diode is connected to the reverse current output terminal of the second switch element, and the cathode of the second freewheeling diode is connected to the DC input terminal of the second switch element.

6. The circuit for driving a three-phase motor according to claim 1, characterized in that: The Boost-PFC module (2) comprises a switch element Q1, a PFC diode D1 and an absorption diode D2; The gate of the switch element Q1 serves as the modulation signal input terminal, the emitter of the switch element Q1 serves as the signal output terminal of the Boost-PFC module (2), and the collector of the switch element Q1 is connected to the DC output terminal of the rectifier bridge module (1); The positive electrode of the PFC diode D1 is connected to the collector of the switch element Q1, and the negative electrode of the PFC diode D1 serves as a DC output end of the Boost-PFC module (2); An anode of the absorption diode D2 is connected to the emitter of the switching element Q1 , and a cathode of the absorption diode D2 is connected to the collector of the switching element Q1 .

7. A method for driving a three-phase motor, characterized in that: The method is implemented by using a circuit for driving a three-phase motor as claimed in any one of claims 1 to 6, and comprises: Acquire a first signal outputted by a signal output terminal of a Boost-PFC module (2); According to a preset mains power signal and the first signal, the power factor is corrected and a modulation signal is input to a modulation signal input terminal of the Boost-PFC module (2); According to the modulation signal, adjusting the duty cycle output by the Boost-PFC module (2) to obtain a first direct current; A three-phase inverter module (4) is used to shunt and invert the first direct current, and output a three-phase alternating current to the three-phase motor (300).

8. The method for driving a three-phase motor according to claim 7, characterized in that: The first signal includes the output voltage of the Boost-PFC module (2) and the output current of the Boost-PFC module (2); and the method of correcting the power factor and inputting a modulation signal to the modulation signal input terminal of the Boost-PFC module (2) according to the preset mains signal and the first signal comprises: Calculating a current power factor according to a preset mains power signal, an output voltage of the Boost-PFC module (2), and an output current of the Boost-PFC module (2); Determine whether the current power factor is greater than the target power factor; if so, maintain the current power factor and input a modulation signal to the modulation signal input end of the Boost-PFC module (2); if not, increase the current power factor until the current power factor is greater than the target power factor and input a modulation signal to the modulation signal input end of the Boost-PFC module (2).

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