Circuit for driving three-phase motor

Abstract

The invention provides a circuit for driving a three-phase motor. The circuit comprises a rectifier bridge module arranged on a circuit substrate, a Boost-PFC module, a three-phase inversion module and a driving module, wherein the Boost-PFC module, the three-phase inversion module and the driving module are integrated on the same DBC substrate. And the DBC substrate is electrically connected to the side surface of the circuit substrate by adopting the same pair of pin groups. The AC input end of the rectifier bridge module is connected with commercial power. The direct current input end of the Boost-PFC module is connected with the direct current output end of the rectifier bridge module. A direct current input end of the three-phase inversion module is connected with a direct current output end of the Boost-PFC module, and three alternating current output ends of the three-phase inversion module are respectively connected with corresponding power supply access ends of the three-phase motor; the power supply access end of the driving module is connected with a first independent power supply. The signal detection end of the driving module is connected with the signal output end of the Boost-PFC module, and the modulation signal output end of the driving module is connected with the modulation signal input end of the Boost-PFC module. Compared with the prior art, the circuit provided by the invention can stably drive the three-phase motor on the premise of meeting the requirements of heat dissipation and high integration level.

Description

Technical Field

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

[0002] With the iteration and update of household appliances, in order to meet the performance requirements of speed regulation, frequency conversion, etc., the drive motors of appliances such as air-conditioning compressors and drum washing machines are gradually adopting three-phase motors. Residential electricity is generally single-phase, and driving the above three-phase motors requires three-phase power supply. Therefore, it is necessary to use a drive circuit to perform phase conversion after connecting the mains to the power supply of such high-power appliances.

[0003] In the prior art, the drive circuit is usually composed 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 drive circuit, the power factor correction module, the rectifier bridge module and the three-phase inverter module need to be designed discretely, that is, the above three modules are designed as independent modules of the circuit and assembled or welded in the circuit substrate. This drive circuit design scheme has a low degree of integration and has the following defects: (1) Due to the discrete setting of the modules, the circuit board needs to be assembled and welded multiple times during the actual production process, which results in high production costs.

[0004] (2) The vibration generated during the operation of the three-phase motor will inevitably affect the driver circuit board itself. The discrete driver circuit has many module solder joints or assembly points that are not concentrated, which makes it easy for components to loosen. Therefore, this type of low-level integrated driver circuit still has the problem of instability.

[0005] (3) The circuit structure itself is not designed reasonably. The driving current output by the existing circuit to the three-phase motor is not stable enough, which makes the working stability of the three-phase motor poor.

[0006] Therefore, the prior art has the problems of low integration and poor stability. Summary of the invention

[0007] The present invention provides a circuit for driving a three-phase motor, which is used to solve the problems of low integration and poor stability in the prior art.

[0008] In a first aspect, to achieve the above-mentioned object, the present invention provides a circuit for driving a three-phase motor, comprising a rectifier bridge module arranged on a circuit substrate and a Boost (boost)-PFC (Power Factor Correction) module, a drive module and a three-phase inverter module integrated on the same DBC (Direct Bond Copper) substrate; the DBC substrate is electrically connected to the side of the circuit substrate using the same pair of pin groups; The DBC substrate includes a ceramic substrate and a multi-layer copper foil, wherein the multi-layer copper foil is arranged on two opposite sides of the ceramic substrate; the multi-layer copper foil includes a power layer, a signal layer and a ground layer connected in sequence; the power layer is connected to the ceramic substrate, and the ground layer is arranged on a 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; The AC input terminal of the rectifier bridge module is used to connect to the mains; The DC input terminal of the Boost-PFC module is connected to the DC output terminal of the rectifier bridge module; The power supply access end of the driving module is connected to an external first independent power supply; the signal detection end of the driving module is connected to the signal output end of the Boost-PFC module; the modulation signal output end of the driving module is connected to the modulation signal input end of the Boost-PFC module; The DC input end of the three-phase inverter module is connected to the DC output end of the Boost-PFC module, and the three AC output ends of the three-phase inverter module are respectively connected to the power supply access ends corresponding to the three-phase motor to be driven.

[0009] 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. 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, 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. 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 utilizing the characteristics of the DBC substrate. Therefore, directly integrating the Boost-PFC module, the three-phase inverter module, and the drive module into the DBC substrate can meet the heat dissipation requirements and improve the degree of circuit integration. On this basis, the DBC substrate uses the same pair of pin groups to be electrically connected to the side of the circuit substrate. The same pin group itself has multiple pins spaced apart from each other, and the DBC substrate uses two pin groups to achieve electrical connection with the circuit substrate, that is, multiple dense connection pins are concentrated on the same DBC substrate for welding or assembly, so that the soldering points or assembly points of the Boost-PFC module, the three-phase inverter module and the drive module connected to the circuit substrate are highly concentrated, and are not easy to loosen, which improves the stability of the drive circuit at the physical structure level. As for the circuit structure, the circuit of the present invention is equipped with a Boost-PFC module to achieve DC boost and reduce grid harmonic pollution. The drive module is powered by an independent power supply to achieve "strong and 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, thereby 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 the three-phase motor under the premise of meeting the requirements of heat dissipation and high integration, solving the problems of low integration and poor stability of the prior art.

[0010] Preferably, it also includes an MCU (Microcontroller Unit) module, the power supply access terminal of the MCU module is connected to an external second independent power supply, the on-off command output terminal of the MCU module is connected to the on-off command 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, and the second signal detection terminal of the MCU module is connected to the AC signal output terminal of the three-phase inverter module.

[0011] Through the above technical scheme, the circuit of the present invention realizes monitoring of the driving module and the three-phase inverter module by setting the MCU module, and can calculate the phase and current value of the output current of the three-phase inverter module by collecting the feedback signal of the driving module and the AC signal of the three-phase inverter module, and according to the phase and current value of the output current, based on the built-in optimization program, outputs the high-frequency on-off instruction of the corresponding phase to the three-phase inverter module through the on-off instruction output terminal, so that the three-phase inverter module regulates the output on-off of the corresponding phase current, improves the current waveform of each phase current, and thus improves the stability of the three-phase motor during operation.

[0012] Preferably, the three-phase inverter module includes a forward current output unit and a reverse current output unit; The DC output terminal of the Boost-PFC module is connected to the DC input terminal of the forward current output unit and the reverse current output unit respectively; The forward current output terminal of the forward current output unit is connected to the power supply input terminal of the three-phase motor to be driven; 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.

[0013] Through the above technical scheme, the forward current output unit in the circuit of the present invention is used to output forward current to the three-phase motor, and the reverse current output unit is used to output reverse current to the three-phase motor. The two current output units output current alternately at a high frequency, so that the three-phase motor can operate smoothly in the AC current with a stable waveform.

[0014] Preferably, the forward current output unit includes 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, 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 access end corresponding to the three-phase motor to be driven.

[0015] Through the above technical solution, the first on-off control subunit is powered by the first independent power supply to achieve "strong and weak isolation". The first switch subunit is controlled by the first on-off control subunit. When the first on-off control subunit outputs an on-signal, the first switch subunit is turned on, and the current of the corresponding phase is output to the three-phase motor. When the first on-off control subunit outputs an off-signal, the first switch subunit is turned 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 of the input three-phase motor, which is beneficial to the frequency conversion and speed regulation of the three-phase motor.

[0016] Preferably, 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, 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; 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.

[0017] Through the above technical solution, the first switch subunit is composed of a first switch element and a first freewheeling diode. The first freewheeling diode is connected in parallel between the forward current output terminal and the DC input terminal of the first switch element, which is beneficial to provide a current freewheeling channel when the first switch element is turned off, ensuring that the current will not be suddenly interrupted, thereby protecting the first switch element. The first freewheeling diode can also smooth current fluctuations and reduce the impact of current mutations on the circuit.

[0018] Preferably, the reverse current output unit includes 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, the switch controlled end of the second switch subunit 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 subunit is connected to the power access end corresponding to the three-phase motor to be driven.

[0019] Preferably, the second switch subunit comprises 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, 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; 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.

[0020] Preferably, the Boost-PFC module includes a switching element Q1, a PFC diode D1 and an absorption diode D2; The gate of the switch element Q1 is used as a modulation signal input terminal, the emitter of the switch element Q1 is used as a signal output terminal, and the collector of the switch element Q1 is connected to the DC output terminal of the rectifier bridge module; 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; 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 .

[0021] Through the above technical solution, the switch element Q1, as the core switch 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 absorption diode D2, also known as the TVS diode, is a circuit protection element. Its main function is to absorb and suppress voltage spikes in the circuit, thereby protecting the switch element Q1.

[0022] Preferably, the switch element Q1 is any one of MOSFET, IGBT or BJT.

[0023] Preferably, the rectifier bridge module adopts a full-bridge rectifier module.

[0024] Through the above technical solution, the full-bridge rectifier circuit can rectify both the positive and negative half-cycles of the mains power, thereby obtaining a smoother DC output.

[0025] In a second aspect, in order to achieve the above object, the present invention further 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 comprises: Obtain a first signal output from a signal output terminal of the Boost-PFC module; According to the preset mains signal and the first signal, the power factor is corrected and a modulation signal is input to the modulation signal input terminal of the Boost-PFC module; According to the modulation signal, the duty cycle of the Boost-PFC module output is adjusted to obtain a first direct current; A three-phase inverter module is used to shunt and invert the first direct current, and output a three-phase alternating current to the three-phase motor.

[0026] Preferably, the first signal includes the output voltage of the Boost-PFC module and the output current of the Boost-PFC module; according to the preset mains signal and the first signal, correcting the power factor and inputting the modulation signal to the modulation signal input terminal of the Boost-PFC module, including: The current power factor is calculated based on the preset mains signal, the output voltage of the Boost-PFC module and the output current of the Boost-PFC module; Determine whether the current power factor is greater than the target power factor. If so, maintain the current power factor and input the 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 the modulation signal to the modulation signal input terminal of the Boost-PFC module.

[0027] The present invention has at least the following advantages: 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 uses the same pair of pin groups to be electrically connected to the side of the circuit substrate, so that the solder joints or assembly points of the Boost-PFC module, the three-phase inverter module, and the drive module connected to the circuit substrate are highly concentrated, and are not easy to loosen, which improves the stability of the drive circuit at the physical structure level. As for the circuit structure, the circuit of the present invention is equipped with a Boost-PFC module to achieve DC boost and reduce grid harmonic pollution. The drive module is powered by an independent power supply to achieve "strong and weak isolation". The drive module is used to correct the power factor and negatively feedback-regulate the DC current output by the Boost-PFC module to the three-phase inverter module, so that the DC current value output by the Boost-PFC module to the three-phase inverter module is maintained within a predetermined range, thereby 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 the three-phase motor while meeting the requirements of heat dissipation and high integration. And the DBC substrate of the present application has strong electromagnetic shielding ability and can achieve high-quality signal transmission.

[0028] 2) The circuit of the present invention realizes monitoring of the driving module and the three-phase inverter module by setting an MCU module. By collecting the feedback signal of the driving 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. According to the phase and current value of the output current of each phase, based on the built-in optimization program, the high-frequency on-off command of the corresponding phase is output to the three-phase inverter module through the on-off command output terminal, so that the three-phase inverter module regulates the output on-off of the corresponding phase current, improves the current waveform of each phase current, and thus improves the stability of the three-phase motor during operation.

[0029] 3) The method of the present invention first obtains the 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 the 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, and output a stable and smooth three-phase AC current to the three-phase motor, thereby improving the stability of the three-phase motor operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 Schematic diagram of a circuit for driving a three-phase motor in Embodiment 1 of the present invention; Figure 2 It is a schematic structural diagram of a circuit for driving a three-phase motor in Embodiment 1 of the present invention arranged on a DBC substrate and a circuit substrate; Figure 3 It is a structural schematic diagram of a DBC substrate provided in an embodiment of the present invention; Figure 4 Schematic diagram of a circuit for driving a three-phase motor in Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of a circuit for driving a three-phase motor in Embodiment 3 of the present invention; Figure 6 The schematic diagram of the circuit of the Boost-PFC module and the three-phase inverter module in the third embodiment of the present invention; Figure 7 This is a layout diagram of electronic components of a DBC substrate of a circuit for driving a three-phase motor in a fourth embodiment of the present invention; Figure 8 Flow chart of a method for driving a three-phase motor in Embodiment 5 of the present invention.

[0032] Reference numerals: 100, circuit substrate; 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 DESCRIPTION

[0033] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0036] This embodiment discloses a circuit for driving a three-phase motor, which is used to stably drive the three-phase motor while meeting the requirements of heat dissipation and high integration.

[0037] Embodiment 1 like Figure 1 As 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 .

[0038] Among them, the AC input end of the rectifier bridge module 1 is connected to the mains, and is used to convert the AC 220V of the mains into a DC 220V output. The Boost-PFC module 2 is used to boost and reduce the harmonic pollution of the power grid, and its DC input end is connected to the DC output end of the rectifier bridge module 1, and is used to boost the DC 220V to a predetermined voltage. 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 its three AC output ends are respectively connected to the power access ends corresponding to 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 DC power into three-phase AC power through inversion to supply the three-phase motor 300.

[0039] On the basis of the above circuit design, the power access end of the driving module 3 is connected to the external first independent power supply (+15V) to achieve "strong and weak isolation" to prevent strong electricity from damaging the driving module 3. The signal detection end of the driving module 3 is connected to the signal output end of the Boost-PFC module 2 to obtain the voltage or current signal of the Boost-PFC module 2. The modulation signal output end of the driving module 3 is connected to the modulation signal input end 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 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, so as to improve the stability and reliability of the circuit network of the three-phase motor 300.

[0040] Further, such as Figure 2 As shown, in order to meet the requirements of heat dissipation and structural stability, the above-mentioned rectifier bridge module 1 is set on the circuit substrate 100, and the Boost-PFC module 2, the drive module 3 and the three-phase inverter module 4 are integrated in the same DBC substrate 200. The DBC substrate 200 is electrically connected to the side of the circuit substrate 100 using the same pair of pin groups 201.

[0041] Through the above structural improvement, the DBC substrate 200, as a direct copper-clad ceramic substrate, has excellent heat dissipation capacity and insulation performance compared with the traditional PCB circuit substrate 100. The circuit of the present invention integrates the Boost-PFC module 2, the three-phase inverter module 4, and the drive module 3 on the same special DBC substrate 200 adapted to the above three modules, realizing the high integration of the Boost-PFC module 2, the three-phase inverter module 4 and the drive module 3, changing the traditional single-board flat structure layout, and using the special DBC substrate 200 to achieve the high integration of the three modules, and improving the space utilization. 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 utilizing 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 into the DBC substrate 200 can meet the heat dissipation requirements and improve the degree of circuit integration. The DBC substrate 200 is electrically connected to the side of the circuit substrate 100 using the same pair of pin groups 201, so that the solder joints or assembly points where the Boost-PFC module 2, the three-phase inverter module 4, and the drive module 3 are connected to the circuit substrate 100 are highly concentrated and less likely to loosen, thereby improving the stability of the drive circuit at the physical structure level.

[0042] Different from the conventional DBC substrate, the above-mentioned special DBC substrate 200 is realized by using a nitrogen baking process, and the special DBC substrate 200 is a highly integrated design based on the Boost-PFC module 2 , the three-phase inverter module 4 , and the drive module 3 .

[0043] See also Figure 3 More specifically, the DBC substrate 200 includes a ceramic substrate and a multi-layer copper foil, the multi-layer copper foil is arranged on two opposite sides of the ceramic substrate; the multi-layer copper foil includes a power layer, a signal layer and a ground layer connected in sequence; the power layer is connected to the ceramic substrate, and the ground layer is arranged on a side of the signal layer away from the ceramic substrate; the signal layer includes a first signal layer and a second signal layer, the driving 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.

[0044] Specifically, the present application also changes the DBC substrate 200. The DBC substrate 200200 is provided with a ceramic substrate 210 and a multi-layer copper foil. The power layer 220, the signal layer and the ground layer 250 are formed by the multi-layer 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 signal of the drive module, the state feedback signal of the power module, etc.

[0045] The copper foil thickness of the grounding layer 250 can be designed according to actual needs. Preferably, the signal layer of the present application includes 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 high-current lines of the Boost-PFC module and the three-phase inverter module) are arranged in layers to reduce electromagnetic coupling between them. In addition, the grounding layer 250 is placed on the side adjacent to the signal layer as a return path for the signal to reduce the loop area and reduce electromagnetic radiation.

[0046] Preferably, a dielectric layer is provided between each layer of copper foil, and the dielectric layer is composed of an insulating material, such as polyimide (PI) or epoxy resin. Preferably, the dielectric layer is polyimide. Polyimide has good insulation properties, mechanical properties and thermal stability, can withstand high temperatures, and 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, electromagnetic shielding materials, such as nano-metal particles or magnetic materials, are 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 to prevent them from propagating in the dielectric layer, thereby reducing electromagnetic coupling. In addition, the surface of the dielectric layer is coated with a coating, so that the roughness of the surface of the dielectric layer is reduced, thereby reducing the scattering and reflection of the electromagnetic signal on the surface of the dielectric layer, thereby reducing electromagnetic coupling. In addition, a groove is provided in the dielectric layer, and the signal layer is embedded in the groove. The groove completely covers the edge of the signal layer, thereby reducing the leakage of the electromagnetic signal to the outside and the coupling with other layers.

[0047] Specifically, the specific production process of the above-mentioned special DBC substrate 200 is as follows: Incoming material inspection>Warehousing>Loading>Printing>Solder paste bonding>Electronic component assembly>Vacuum reflow component welding>Reflow soldering appearance inspection>Ultrasonic cleaning>Silver glue bonding>Bake>AL wire welding>Plasma cleaning>Pd-plated copper wire / gold wire welding>Door inspection>Plastic sealing>Curing>Electroplating>Electroplating appearance inspection>Electroplating baking>Rebar cutting and forming>Voltage resistance test>Room temperature test>Laser marking>FQA electrical test>Appearance inspection>FQA inspection>Finished product packaging.

[0048] Different from the prior art, the above-mentioned special DBC substrate 200 uses vacuum reflow to complete solder joint welding, so that each pad of the highly integrated DBC substrate 200 printed board is heated evenly, thereby making it possible to weld each dense solder joint of the above-mentioned several large modules. On this basis, the DBC substrate 200 also uses ultrasonic technology to clean impurities in the solder joints to avoid short circuits in densely distributed solder joints due to bridging of conductive impurities. After ultrasonic cleaning, silver glue is used to fix the crystal to enhance the heat dissipation effect and the adhesion ability of electronic components.

[0049] Compared with the prior art, the circuit of the present invention can stably drive the three-phase motor 300 while meeting the requirements of heat dissipation and high integration.

[0050] More specifically, the present application also provides a detailed manufacturing process of the DBC substrate 200: A suitable ceramic substrate 210 is selected according to application requirements, and the surface of the ceramic substrate 210 is processed by chemical cleaning or physical polishing to remove impurities and pollutants on the surface, thereby ensuring the surface flatness and cleanliness of the ceramic substrate 210 .

[0051] Select copper foil: For the power layer 220, select thicker copper foil with a thickness of 200-500μm or even thicker to meet the needs of large current transmission. For the signal layer (including the first signal layer 230 and the second signal layer 240), select relatively thin copper foil, usually about 35-70μm thick, to reduce signal transmission loss and electromagnetic interference. For the grounding layer 250, select copper foil of 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 impurities such as oil and oxides on the surface. Chemical cleaning agents or physical cleaning methods, such as ultrasonic cleaning, can be used to ensure the cleanliness of the copper foil surface. Surface roughening of the copper foil, such as by chemical etching or mechanical polishing, increases the roughness of the copper foil surface, which helps to improve the bonding strength between the copper foil and the ceramic substrate 210.

[0052] The treated copper foil is placed on the ceramic substrate 210 and heated to about 1065°C in a high temperature furnace. 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, thereby achieving a strong bond between the copper foil and the ceramic substrate 210. The temperature, time and atmosphere during the bonding process are precisely controlled to ensure the quality and consistency of the bonding. The heating process needs to be slowly heated to avoid stress between the copper foil and the ceramic substrate 210 due to rapid temperature changes, which affects the bonding strength.

[0053] The designed circuit pattern of the power layer 220 is transferred to the copper foil using photolithography technology.

[0054] The first signal layer 230 and the second signal layer 240 are also subjected to photolithography and etching processes.

[0055] First, photoresist is coated on the copper foil, and the signal layer circuit pattern including the high-frequency drive signal of the drive module, the state feedback signal of the power module, etc. is exposed through a mask, and then developed to expose the copper foil portion to be retained. Then, an etching process is used to remove the excess copper foil to form a circuit pattern of the first signal layer 230. Then, on the basis of the first signal layer 230, the copper layer of the second signal layer 240 is electroplated, and a circuit pattern is formed on the second signal layer 240 using exposure, development, and etching processes. Then, according to the design requirements, the control signal of the drive module is arranged in the first signal layer 230, and the related signals of the high-current circuit of the Boost-PFC module and the three-phase inverter module are arranged in the second signal layer 240, so as to realize the hierarchical arrangement of high-speed signals and power signals and reduce electromagnetic coupling.

[0056] The copper foil circuit pattern of the grounding layer 250 is made and arranged on the side of the signal layer away from the ceramic substrate 210. The copper foil of the grounding layer 250 is also formed into the required grounding network through photolithography and etching processes to provide a stable reference potential for the entire circuit and serve as a return path for the signal to reduce the loop area and reduce electromagnetic radiation.

[0057] It should be noted that, between the production of different copper foil layers, a coating process is also used to evenly coat liquid polyimide on the formed copper foil layer, and then perform a curing process to form a solid dielectric layer.

[0058] The circuit principle of this embodiment is: After the AC 220V mains current is rectified by the rectifier bridge module 1, a DC current is obtained and flows into the Boost-PFC module 2. During this period, the driving module 3 calculates the power factor of the boosted voltage of the Boost-PFC module 2, corrects the power factor, and adjusts the output current of the Boost-PFC module 2 so that the output current value of the Boost-PFC module 2 reaches 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.

[0059] Embodiment 2 like Figure 5 As shown, based on the first embodiment, the circuit for driving a three-phase motor disclosed in this embodiment further includes an MCU module 5.

[0060] Among them, the power access end of the MCU module 5 is connected to an external second independent power supply (+5V) to achieve "strong and weak isolation" so that the MCU module 5 can work in a stable power supply environment. The first signal detection end of the MCU module 5 is connected to the feedback signal output end of the drive module 3, and the second signal detection end of the MCU module 5 is connected to the AC signal output end of the three-phase inverter module 4 to monitor the drive module 3 and the three-phase inverter module 4. The on-off command output end of the MCU module 5 is connected to the on-off command receiving end of the three-phase inverter module 4 to achieve the regulation of the three-phase inverter module 4 by the MCU module 5.

[0061] In this embodiment, the chip model of the MCU module 5 can adopt the IMC302A series chip, which is an intelligent power control chip that can meet the output power regulation, frequency modulation and speed change requirements of the three-phase motor 300.

[0062] Through the above circuit design, the MCU module 5 collects the feedback signal of the driving module 3 and the AC signal of the three-phase inverter module 4, and can calculate the phase and current value of the output current of each phase of the three-phase inverter module 4, and according to the phase and current value of the output current of each phase, based on 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, so that the three-phase inverter module 4 regulates the output on-off of the corresponding phase current, thereby improving the current waveform of each phase current, and then improving the stability of the three-phase motor 300 during operation.

[0063] Embodiment 3 like Figure 5 As shown, based on the second embodiment, the embodiment discloses a circuit for driving a three-phase motor, wherein the rectifier bridge module 1 adopts a full-bridge rectifier module, and rectifies both the positive and negative half-cycles of the AC power through full-bridge rectification, so that the current output by the rectifier bridge module 1 can be smoother, which is beneficial to reduce the impact when the three-phase motor 300 starts or stops, and improve the running stability of the three-phase motor 300.

[0064] 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 switch element Q1 , a PFC diode D1 and an absorption diode D2 .

[0065] Among them, Figure 5 As 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 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 2. The anode of the absorption diode D2 is connected to the emitter of the switching element Q1, and the cathode of the absorption diode D2 is connected to the collector of the switching element Q1.

[0066] It should be noted that the Boost-PFC module 2 is also provided with a large capacitor filter 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 cathode of the PFC diode D1, so as to improve the stability of the output current.

[0067] Through the above circuit design, the switch element Q1 is regulated by the driving module 3 and can be turned 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 the voltage spike in the circuit, and play a role in protecting the switch element Q1.

[0068] Preferably, the switch element Q1 can be any one of MOSFET, IGBT or BJT, among which IGBT has the best performance and can meet the daily needs of household appliances. For some electrical appliances that do not require high switching frequency or have low power, using MOSFET as the switch element Q1 can reduce production costs. In this embodiment, in order to supply stable AC power to the three-phase motor 300, the circuit of the present invention adopts a method of alternating the output current direction at a high frequency.

[0069] Specifically, the three-phase inverter module 4 includes a forward current output unit 41 and a reverse current output unit 42. The DC output end of the Boost-PFC module 2 is connected to the DC input end of the forward current output unit 41 and the reverse current output unit 42 respectively. The forward current output end of the forward current output unit 41 is connected to the power supply access end of the three-phase motor 300. The reverse current output end of the reverse current output unit 42 is connected to the power supply access end of the three-phase motor 300.

[0070] More specifically, the forward current output unit 41 includes 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 a first independent power supply (+15V) to achieve "strong-weak isolation".

[0071] 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 access end corresponding to the three-phase motor 300.

[0072] In this embodiment, the first on-off control subunit is Figure 4The driving chip U1 shown in the figure, and the first switch subunit includes IGBT tubes Q1, Q2 and Q3. The driving chip U1 is provided with an input pin connected to the MCU module 5 to receive the instruction output by the MCU module 5. The output pin of the driving chip U1 is used as the on-off control terminal of the first on-off control subunit, and is respectively connected to the base of the IGBT tubes Q1, Q2 and Q3 to control the on and off of the IGBT tubes Q1, Q2 and Q3.

[0073] Further, the first switch subunit includes a first switch element and a first freewheeling diode. In the present embodiment, the first switch subunit generally refers to IGBT tubes Q1, Q2 and Q3, and the first freewheeling diode generally refers to freewheeling diodes D3, D4 and D5. 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 positive pole of the first freewheeling diode is connected to the forward current output end of the first switch element, and the negative pole of the first freewheeling diode is connected to the DC input end of the first switch element.

[0074] 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 be suddenly interrupted, thereby protecting the first switching element. The first freewheeling diode can also smooth current fluctuations and reduce the impact of current mutations on the circuit.

[0075] Similar to the circuit design structure of the forward current output unit 41, in this embodiment, the reverse current output unit 42 includes 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 the second independent power supply (+5V). The DC input terminal of the second switch subunit is connected to the DC output terminal of the Boost-PFC module 2, the switch controlled terminal of the second switch subunit is connected to the on-off control terminal corresponding to the second on-off control subunit, and the reverse current output terminal of the second switch subunit is connected to the power supply access terminal corresponding to the three-phase motor 300.

[0076] Different from the forward current output unit 41, in this embodiment, the second on-off control subunit is Figure 4 The driving chip U2 in the embodiment, and the second switching element of the second switching sub-unit generally refers to IGBT tubes Q5, Q6 and Q7.

[0077] More specifically, 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 positive electrode of the second freewheeling diode is connected to the reverse current output end of the second switch element, and the negative electrode of the second freewheeling diode is connected to the DC input end of the second switch element.

[0078] In this embodiment, when the forward current output unit 41 is outputting the forward current, the three second switch sub-units are always in the off state.

[0079] Compared with the prior art, this embodiment makes specific improvements to the Boost-PFC module 2 and the three-phase inverter module 4, and adopts full-bridge rectification technology for rectification, so that the output three-phase current of the circuit of the present invention has excellent stability, which is conducive to the smooth operation of the three-phase motor.

[0080] Embodiment 4 On the basis of the third embodiment, the present embodiment integrates all the above-mentioned IGBTs and diodes on the DBC substrate 200 , and sets a pair of pin groups 201 for connecting to the circuit substrate 100 on both sides of the DBC substrate 200 .

[0081] like Figure 7 As shown, this embodiment optimizes the process layout of 17 chips (IGBT, diode, driver chip U1 and driver chip U2) on the DBC substrate 200.

[0082] Specifically, a steel mesh with 17 chips is formed on the DBC substrate 200 using the nitrogen baking process described in CN116741764 A, so that the layout of these chips is more compact, stable and conducive to assembly line production.

[0083] Preferably, the chip of the driving module 3 of this embodiment may adopt the bridgeless PFC control chip described in CN116741764 A.

[0084] Compared with the prior art, this embodiment ensures that the position of each chip will not drift by increasing the steel mesh opening ratio and compact design, thereby further improving the stability of the circuit of the present invention in terms of physical structure.

[0085] Embodiment 5 like Figure 8 As 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 recorded in the above embodiment. The method of the present invention includes: S10: Acquire a first signal outputted by a signal output terminal of the Boost-PFC module.

[0086] It should be noted that the first signal may be a boosted voltage signal of the Boost-PFC module or a current signal.

[0087] S20: According to the preset mains signal and the first signal, the power factor is corrected and a modulation signal is input to the modulation signal input terminal of the Boost-PFC module.

[0088] It should be noted that the mains power signal is AC 220V / 50Hz. Generally, such a signal is a known signal.

[0089] S30: According to the modulation signal, adjust the duty cycle of the Boost-PFC module output to obtain a first direct current.

[0090] S40: using 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.

[0091] Furthermore, the above S20 is specifically: According to the preset mains signal and the first signal, correcting the power factor and inputting the modulation signal to the modulation signal input terminal of the Boost-PFC module comprises: The current power factor is calculated based on the preset mains signal, the output voltage of the Boost-PFC module and the output current of the Boost-PFC module; 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 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. The first signal includes the output voltage of the Boost-PFC module and the output current of the Boost-PFC module.

[0092] Specifically, the calculation algorithm of the current power factor is: ; in, 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.

[0093] like If the power factor is less than the target power factor, the duty cycle of the output current of Boost-PFC module 2 is modulated to increase ,improve , until it is greater than the target power factor.

[0094] Compared with the prior art, the method of the present invention first obtains the 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, inputs the 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, and output a stable and smooth three-phase AC current to the three-phase motor, thereby improving the stability of the three-phase motor operation.

[0095] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above-mentioned method embodiment; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc. Various media that can store program codes.

[0096] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still 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.

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 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.

4. The circuit for driving a three-phase motor according to claim 3, characterized in that: 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.

5. The circuit for driving a three-phase motor according to claim 4, 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.

6. The circuit for driving a three-phase motor according to claim 3, 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.

7. The circuit for driving a three-phase motor according to claim 6, 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.

8. 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 .

9. A method for driving a three-phase motor, characterized in that: The method is implemented by using the circuit for driving a three-phase motor as described in any one of claims 1 to 8, 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).

10. The method for driving a three-phase motor according to claim 9, 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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