Low-power-consumption frequency conversion washing machine control system

Abstract

The utility model provides a low-power-consumption frequency conversion washing machine control system, which is applied to the technical field of washing machine control systems and comprises a driving control board and a display board, and information is transmitted between the display board and the driving control board through UART (Universal Asynchronous Receiver / Transmitter) communication; a power supply circuit is configured on the driving control board and comprises an input module, a switch module and an output module, an alternating-current power supply is connected to the input module for filtering and rectifying to generate direct-current voltage and then input the direct-current voltage to the switch module, and the switch module generates corresponding alternating-current voltage according to the switching frequency of a switching tube; various direct-current voltages are output after being filtered and rectified by the output module; the direct-current voltage comprises a direct-current voltage I, a direct-current voltage II and a direct-current voltage III, and the direct-current voltage II is connected to the step-down converter U4 and then is subjected to step-down to form the direct-current voltage III. Basic functions of the washing machine are achieved through mutual cooperation of the driving control board and the display board, and power consumption can be reduced when the washing machine is in a sleep state through circuit design.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of washing machine control system, specifically relates to a low -power consumption's variable frequency washing machine control system. BACKGROUND

[0002] Automatic washing machine refers to the device that under the control of program setting ware, it is automatic to complete clothes washing, rinsing and dewatering according to requirement.

[0003] After the installation of domestic washing machine, it is generally on the power even in the shutdown state, this will produce certain power consumption, namely shutdown loss. The power consumption of shutdown state is redundant consumption, and reducing the power consumption of shutdown state can effectively save electric energy. CONTENT OF UTILITY MODEL

[0004] In view of the above problems existing in the prior art, the utility model aims at providing a low-power consumption's variable frequency washing machine control system, through the mutual cooperation between drive control board and display board, the basic function of washing machine is realized, and the power consumption can be reduced when washing machine is in sleep state through circuit design.

[0005] A low-power consumption's variable frequency washing machine control system, including drive control board and display board, display board and drive control board between through UART communication transmission information;Drive control board is equipped with power supply circuit, and the power supply circuit includes input module, switch module, output module, and the switch module includes transformer T1 and power supply chip U2, and the power supply chip U2 is built-in with switch tube;After the alternating current power supply is connected input module and is filtered, rectified and generates direct current voltage, then is input to switch module, and switch module generates corresponding alternating current voltage according to the switching frequency of switch tube, and after filtering, rectification of output module, multiple direct current voltages are output to realize power supply;Direct current voltage includes direct current voltage one, direct current voltage two, direct current voltage three, wherein, direct current voltage two is connected into voltage reducer U4 and is reduced to form direct current voltage three.

[0006] Preferably, the input module comprises a connection terminal CN1, a protection unit, a filter unit and a rectifier unit, an alternating voltage is connected through the connection terminal CN1, after noise suppression, overcurrent protection and overvoltage protection by the protection unit, the alternating voltage is filtered and noise suppressed by the filter unit, and then the alternating voltage is converted into a direct current voltage by the rectifier unit; the protection unit comprises a fuse F1, a capacitor CY3, a capacitor CY4 and a resistor RV1, wherein the capacitor CY3 and the capacitor CY4 are used for suppressing common mode noise of the input voltage, the fuse F1 is used for overcurrent protection, and the resistor RV1 is used for overvoltage protection; the filter unit comprises an inductor L1, an inductor L2, an inductor L3, a capacitor CX1, a capacitor CX2 and a capacitor CX3, wherein the inductor L1 is used for suppressing common mode high frequency noise, the inductor L2 and the inductor L3 are used for suppressing differential mode high frequency noise, and the capacitor CX1, the capacitor CX2 and the capacitor CX3 are used for suppressing noise; and the rectifier unit comprises a rectifier bridge BR1, which is used for converting the filtered alternating voltage into a direct current voltage.

[0007] Preferably, the power supply chip U2 is connected to the direct current voltage output by the input module through an adjusting unit, the adjusting unit comprises a resistor R1, a resistor R2, a capacitor C1, a resistor R3 and a diode D4, wherein the resistor R1, the resistor R2 and the resistor R3 form a voltage dividing network for dividing the direct current voltage output by the input module, the divided direct current voltage is connected to the power supply chip U2 through the diode D4 to supply power to the power supply chip U2, the diode D4 is used for ensuring the correct direction of power supply, and the capacitor C1 is used for filtering high frequency noise in the high voltage.

[0008] Preferably, the output module comprises an output unit one, which outputs a direct current voltage one of 12V, the output unit one comprises a diode D1, a resistor R7, a capacitor C3, a capacitor EC4, a capacitor C4 and a resistor R8, wherein the resistor R7 and the capacitor C3 are connected in series and connected to both ends of the diode D1, one end of the diode D1 is connected to a secondary winding of a transformer T1, and the other end is used as an output end to output the direct current voltage one, the output end of the direct current voltage one is connected to the capacitor EC4, the capacitor C4 and the resistor R8 in parallel, and the other ends of the capacitor EC4, the capacitor C4 and the resistor R8 are grounded.

[0009] Preferably, the output module comprises an output unit two, which outputs a direct current voltage two of 15V and a direct current voltage three of 5V; the output unit two comprises a diode D2, a resistor R9, a capacitor C5, a capacitor EC5, a capacitor C6 and a resistor R10, wherein the resistor R9 and the capacitor C5 are connected in series and connected to both ends of the diode D2, one end of the diode D2 is connected to a secondary winding of a transformer T1, and the other end is used as an output end to output the direct current voltage two, the output end of the direct current voltage two is connected to the capacitor EC5, the capacitor C6 and the resistor R10 in parallel, and the other ends of the capacitor EC5, the capacitor C6 and the resistor R10 are grounded.

[0010] Preferably, the output unit two further comprises a step-down converter U4 connected to the second DC voltage, converts the second DC voltage into a third DC voltage and outputs the third DC voltage; the VIN pin of the step-down converter U4 is connected to the second DC voltage, and the VIN pin is connected with the parallel capacitor C8 and capacitor C10; the VOUT pin and the SW pin of the step-down converter U4 are directly connected with the inductor L4; the VOUT pin of the step-down converter U4 outputs the third DC voltage as an output terminal; the VOUT pin of the step-down converter U4 is connected with the parallel capacitor C9, capacitor C11 and capacitor EC6, and the other end of the capacitor C9, capacitor C11 and capacitor EC6 is grounded.

[0011] Preferably, the power supply circuit further comprises a feedback module, the feedback module comprises a triode Q2, for feeding back the signal of the secondary winding of the transformer T1 to the power supply chip U2, so that the power supply chip U2 can adjust the duty cycle of the PWM signal according to the feedback signal.

[0012] Preferably, the drive control board is further provided with a zero-crossing detection circuit, the zero-crossing detection circuit comprises resistors R35, R34, R30, R31, a diode D30, a capacitor C30, a triode Q30, resistors R32, R33, and a capacitor C31; the base of the triode Q30 is connected with the parallel capacitor C30, diode D30 and resistor R31, the other end of the capacitor C30, diode D30 and resistor R31 is grounded, and the other end of the resistor R31 away from the ground is further connected with the resistor R30, resistor R34 and resistor R35 connected in series; the other end of the resistor R35 is connected with the detection point of the power supply circuit to input the AC_L' signal; the emitter of the triode Q30 is grounded, the collector of the triode Q30 is connected with the resistor R32, the other end of the resistor R32 is connected with the supply voltage, and the resistor R33 and capacitor C31 connected in series are connected between the emitter and the collector of the triode Q30, and the AC_INT signal between the resistor R33 and capacitor C31 is input into the control board main control chip MCU.

[0013] Preferably, the drive control board is further provided with a bus voltage detection circuit, the bus voltage detection circuit comprises resistors R80, R81, R82, R83, R84, capacitors C80, C81, and a diode D80; the resistors R80, R81, R82 and R83 are connected in series, and the other end of the resistor R80 is connected with the detection point P of the power supply circuit; the resistors R82 and R83 are connected with the parallel resistor R84 and capacitor C80, and the other end of the resistor R84 and capacitor C80 is grounded; the other end of the resistor R83 is connected with the parallel diode D80 and capacitor C81, and the other end of the capacitor C81 is grounded; the other end of the diode D80 is connected with the supply voltage, and the signal Vfb_bus between the diode D80, capacitor C81 and resistor R83 is input into the control board main control chip MCU.

[0014] The low-power frequency conversion washing machine control system has the advantages that through the cooperation between the driving control board and the display board, the display board transmits instructions to the driving control board, various functions of the washing machine are realized in the working mode, low power consumption is maintained in the sleep mode, and shutdown loss can be reduced.

[0015] The power supply circuit in the driving control board is designed to convert the input AC voltage into various DC voltages to form various power supply voltages for system selection.

[0016] The control system has precise voltage stabilization control and fast protection response, ensures stable operation under various working conditions, perfect protection function reduces damage to core components, and prolongs the service life of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, and are used together with the embodiments of the present application to explain the present application, and do not constitute a limitation on the present application. In the drawings:

[0018] Figure 1 is a circuit diagram of the present application;

[0019] Figure 2 is a circuit diagram of the power supply circuit of the present application;

[0020] Figure 3 is a circuit diagram of the input module of the power supply circuit of the present application;

[0021] Figure 4 is a circuit diagram of the output module of the power supply circuit of the present application;

[0022] Figure 5 is a circuit diagram of the zero-crossing detection circuit of the present application;

[0023] Figure 6 is a circuit diagram of the bus voltage detection circuit of the present application;

[0024] Figure 7 is a work flow chart of the present application. DETAILED DESCRIPTION

[0025] Embodiment one

[0026] As Figure 1As shown, a low-power variable frequency washing machine control system includes a drive control board and a display board, the drive control board includes a control board main control chip MCU, the display board includes a display board main control chip MCU, and the display board and the drive control board transmit information through UART communication. In order to realize the function of the washing machine, the load connected to the drive control board includes a motor, a water inlet valve, a tractor, a drainage pump, a soft valve and a door lock, and the display board is connected with a water level sensor, a safety switch and function buttons.

[0027] The drive control board is provided with a power supply circuit, such as Figure 2 As shown, the power supply circuit includes an input module, a switching module, an output module and a feedback module. The power supply circuit is used to convert the input AC voltage into corresponding DC voltage to supply power to the display board or the load. The DC voltage in this embodiment includes a first DC voltage of 12V, a second DC voltage of 15V and a third DC voltage of 5V, wherein the first DC voltage is used to supply power to the water inlet valve, the tractor, the drainage pump, the soft valve and the door lock on the drive control board, the second DC voltage is used to supply power to the IPM of the motor on the drive control board, and the third DC voltage is used to supply power to the control board main control chip MCU or other weak current units.

[0028] As shown in Figure 3 The input module includes a connection terminal CN1, a protection unit, a filter unit and a rectifier unit. The protection unit includes a fuse F1, a capacitor CY3, a capacitor CY4 and a resistor RV1, wherein the capacitor CY3 and the capacitor CY4 are used to suppress the common mode noise of the input voltage, the fuse F1 is used for overcurrent protection, and the resistor RV1 is used for overvoltage protection.

[0029] The filter unit includes inductors L1, L2, L3, capacitors CX1, CX2 and CX3, wherein the inductor L1 is a common mode inductor for suppressing common mode high frequency noise and reducing electromagnetic interference, the inductors L2 and L3 are differential mode inductors for suppressing differential mode high frequency noise and ensuring power quality, and the capacitors CX1, CX2 and CX3 cooperate with the inductors to form a filter network for further suppressing noise.

[0030] The filter unit is also connected with a discharge chip U5, and the type of the discharge chip U5 in this embodiment is PN8200. At the input end of the power supply circuit, the discharge chip U5 controls the charging and discharging of the X-class capacitor in the filter unit to ensure the safety of the operation after power failure.

[0031] The rectifier unit includes a rectifier bridge BR1 for converting the filtered AC voltage into a DC voltage. The output end of the rectifier bridge BR1 is also connected with a capacitor EC1 for filtering the rectified DC voltage to improve voltage stability.

[0032] In addition, the input module further comprises a relay K1, which is used as a switch control of the power supply, and a diode D5 connected to the relay K1, which is used to protect the coil of the relay K1 from being damaged by voltage backlashes.

[0033] The switch module comprises a transformer T1 and a power supply chip U2. As shown in Figure 3 The power supply chip U2 is connected to the DC voltage output by the input module through an adjusting unit, which comprises a resistor R1, a resistor R2, a capacitor C1, a resistor R3 and a diode D4. The resistor R1, the resistor R2 and the resistor R3 form a voltage dividing network, which is used to divide the DC voltage output by the input module. The divided DC voltage is connected to the power supply chip U2 through the diode D4 to supply power to the power supply chip U2. The diode D4 is used to ensure the correct direction of the power supply, and the capacitor C1 is used to filter high-frequency noise in the high voltage.

[0034] The power supply chip U2 is built-in with a switch tube, which is connected to the primary winding of the transformer T1. The PWM signal of the power supply chip U2 controls the on-off frequency of the switch tube to drive the transformer T1 to work. The primary winding of the transformer T1 receives a high-frequency switching signal, and the secondary winding outputs a corresponding DC voltage. The output DC voltage can be adjusted by changing the high-frequency switching signal. Specifically, when the switch tube is turned on, the primary winding of the transformer T1 stores magnetic field energy; when the switch tube is turned off, the secondary winding of the transformer T1 releases energy, so that the secondary winding provides an output voltage.

[0035] The output module comprises an output unit one and an output unit two. The output unit one outputs a 12V DC voltage one, and the output unit two outputs a 15V DC voltage two and a 5V DC voltage three.

[0036] As shown in Figure 4 The output unit one comprises a diode D1, a resistor R7, a capacitor C3, a capacitor EC4, a capacitor C4 and a resistor R8. The resistor R7 and the capacitor C3 are connected in series and connected to the two ends of the diode D1, respectively. One end of the diode D1 is connected to the secondary winding of the transformer T1, and the other end is used as an output terminal to output the DC voltage one. The output terminal of the DC voltage one is connected to the capacitor EC4, the capacitor C4 and the resistor R8 in parallel, and the other ends of the capacitor EC4, the capacitor C4 and the resistor R8 are grounded.

[0037] The output unit two comprises a diode D2, a resistor R9, a capacitor C5, a capacitor EC5, a capacitor C6 and a resistor R10. The resistor R9 and the capacitor C5 are connected in series and connected to the two ends of the diode D2, respectively. One end of the diode D2 is connected to the secondary winding of the transformer T1, and the other end is used as an output terminal to output the DC voltage two. The output terminal of the DC voltage two is connected to the capacitor EC5, the capacitor C6 and the resistor R10 in parallel, and the other ends of the capacitor EC5, the capacitor C6 and the resistor R10 are grounded.

[0038] In addition, the output unit two further comprises a step-down converter U4, which is connected to the direct current voltage two, converts the direct current voltage two into a direct current voltage three and outputs. Specifically, the VIN pin of the step-down converter U4 is connected to the direct current voltage two, and the parallel connection of the capacitor C8 and the capacitor C10 is connected to the VIN pin; the VOUT pin and the SW pin of the step-down converter U4 are directly connected to the inductor L4; the VOUT pin of the step-down converter U4 outputs the direct current voltage three as an output terminal; and the parallel connection of the capacitor C9, the capacitor C11 and the capacitor EC6 is connected to the VOUT pin of the step-down converter U4, and the other ends of the capacitor C9, the capacitor C11 and the capacitor EC6 are grounded.

[0039] As shown in Figure 2 The feedback module comprises a triode Q2, which is configured to feed back the signal of the secondary winding of the transformer T1 to the power supply chip U2, so that the power supply chip U2 can adjust the duty cycle of the PWM signal according to the feedback signal, thereby adjusting the energy transmission amount of the primary winding, and finally realizing the voltage stabilization of the output voltage.

[0040] As shown in Figure 5 The drive control board is further provided with a zero-crossing detection circuit, which comprises the resistor R35, the resistor R34, the resistor R30, the resistor R31, the diode D30, the capacitor C30, the triode Q30, the resistor R32, the resistor R33 and the capacitor C31.

[0041] The base of the triode Q30 is connected to the parallel connection of the capacitor C30, the diode D30 and the resistor R31, and the other ends of the capacitor C30, the diode D30 and the resistor R31 are grounded; the resistor R31 is further connected to the resistor R30, the resistor R34 and the resistor R35 in sequence at the end away from the ground, and the other end of the resistor R35 is connected to the detection point of the power supply circuit to input the AC_L' signal.

[0042] The emitter of the triode Q30 is grounded, the collector of the triode Q30 is connected to the resistor R32, the other end of the resistor R32 is connected to the direct current voltage three, and the resistor R33 and the capacitor C31 are connected in series between the emitter and the collector of the triode Q30; the AC_INT signal between the resistor R33 and the capacitor C31 is input into the main control chip MCU of the control board, and when the alternating voltage crosses zero, the zero-crossing detection circuit can output a clear jump signal as an indication signal of the zero-crossing point, facilitating the subsequent operation of the main control chip MCU.

[0043] As shown in Figure 6 The drive control board is further provided with a bus voltage detection circuit, which comprises the resistor R80, the resistor R81, the resistor R82, the resistor R83, the resistor R84, the capacitor C80, the capacitor C81 and the diode D80.

[0044] Among them, the resistance R80, the resistance R81, the resistance R82, the resistance R83 are connected in series, the other end of the resistance R80 is connected with the detection point P of the power supply circuit. The resistance R82, the resistance R83 are connected with the parallel resistance R84, the capacitor C80, the other end of the resistance R84, the capacitor C80 is grounded. The other end of the resistance R83 is connected with the parallel diode D80, the capacitor C81, the other end of the capacitor C81 is grounded, the other end of the diode D80 is connected with the direct current voltage three, the signal Vfb_bus between the diode D80, the capacitor C81, the resistance R83 is connected with the control board main control chip MCU.

[0045] As shown in Figure 3 , the power supply circuit is provided with a detection point P of a bus voltage detection circuit, the bus voltage detection circuit converts the high voltage bus signal into a stable and safe detection signal Vfb_bus through voltage division, filtering and clamping protection, and provides a reliable voltage reference for the control and protection of the subsequent circuit.

[0046] Working principle: the low-power variable frequency washing machine control system, as shown in Figure 7 , the washing machine is powered on, and the drive control board and the display board are initialized in hardware and software respectively. Within 20S after the washing machine is powered on or the running is completed, the display board scans the function keys and sends a reset instruction to the drive control board.

[0047] Determine whether there is a start signal at this time, if there is a start signal, the display board sends a related instruction to the drive control board, the drive control board drives the related load to run and completes the corresponding washing machine function. After the washing machine function is run, the display board scans the function keys again and sends a reset instruction to the drive control board, and then determines whether there is a start signal at this time.

[0048] If there is no start signal of the washing machine, the display board sends a sleep instruction to the drive control board, and the display board and the drive control board enter the sleep mode at this time, reducing the power consumption of the shutdown. In the sleep mode, if the drive control board receives the communication instruction of the display board, the drive control board is automatically awakened to drive the corresponding load to run.

[0049] When the washing machine enters the sleep mode, the power consumption is mainly concentrated in the power supply circuit, the zero-crossing detection circuit and the bus voltage detection circuit. In order to reduce the power consumption of the power supply circuit, a discharge chip U5 with low power consumption is selected to replace the discharge resistor. In order to reduce the zero-crossing detection circuit, the resistance value of the resistor R35 is set to 1MΩ, the resistance value of the resistor R34 and the resistor R30 is set to 470KΩ, and at the same time, in order to ensure that the output waveform of the zero-crossing detection circuit is consistent with the frequency of the input alternating current waveform, the resistance value of R31 is adjusted to 11KΩ. In order to reduce the power consumption of the bus voltage detection circuit, the resistor R80, the resistor R81 and the resistor R82 are set to be precision resistors with a resistance value of 1MΩ, and the resistor R84 is set to be a precision resistor with a resistance value of 24KΩ. The actual measured power consumption of the variable frequency washing machine control system in the sleep mode after the system is turned off in the embodiment is 0.39W, which can effectively reduce the power consumption.

[0050] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A low power consumption variable frequency washing machine control system, characterized by, The display panel and the driving control panel transmit information through UART communication; The driving control panel is provided with a power supply circuit, which comprises an input module, a switching module and an output module, the switching module comprises a transformer T1 and a power supply chip U2, and the power supply chip U2 is internally provided with a switching tube; After the alternating current power is filtered and rectified in the input module, a direct current voltage is generated and input to the switching module, the switching module generates corresponding alternating current voltages according to the switching frequency of the switching tube, and after filtering and rectification by the output module, a plurality of direct current voltages are output to realize power supply; The direct current voltage comprises a direct current voltage one, a direct current voltage two and a direct current voltage three, wherein the direct current voltage two is input to a voltage reduction converter U4 to form the direct current voltage three.

2. The low power consumption variable frequency washing machine control system according to claim 1, wherein, The input module comprises a connection terminal CN1, a protection unit, a filter unit and a rectifier unit, the alternating current voltage is input through the connection terminal CN1, and after noise suppression, overcurrent protection and overvoltage protection of the protection unit, the alternating current voltage is filtered and noise suppressed by the filter unit, and then rectified by the rectifier unit to form a direct current voltage; The protection unit comprises a fuse F1, capacitors CY3 and CY4 and a resistor RV1, wherein the capacitors CY3 and CY4 are used to suppress common mode noise of the input voltage, the fuse F1 is used for overcurrent protection, and the resistor RV1 is used for overvoltage protection; The filter unit comprises inductors L1, L2 and L3, capacitors CX1, CX2 and CX3, wherein the inductor L1 is used to suppress common mode high frequency noise, the inductors L2 and L3 are used to suppress differential mode high frequency noise, and the capacitors CX1, CX2 and CX3 are used to suppress noise; The rectifier unit comprises a rectifier bridge BR1, which is used to convert the filtered alternating current voltage into a direct current voltage.

3. The low power consumption variable frequency washing machine control system according to claim 1, wherein, The power supply chip U2 is connected to the direct current voltage output by the input module through an adjusting unit, the adjusting unit comprises resistors R1, R2 and R3, a capacitor C1 and a diode D4, wherein the resistors R1, R2 and R3 form a voltage dividing network for dividing the direct current voltage output by the input module, the divided direct current voltage is input to the power supply chip U2 through the diode D4 to realize power supply of the power supply chip U2, the diode D4 is used to ensure the correct direction of power supply, and the capacitor C1 is used to filter high frequency noise in the high voltage.

4. The low power consumption variable frequency washing machine control system according to claim 1, wherein, The output module comprises an output unit one, which outputs a 12V direct current voltage one, the output unit one comprises a diode D1, a resistor R7, a capacitor C3, capacitors EC4 and C4 and a resistor R8, wherein the resistor R7 and the capacitor C3 are connected in series and connected to both ends of the diode D1, one end of the diode D1 is connected to the secondary winding of the transformer T1, and the other end is used as an output end to output the direct current voltage one, the output end of the direct current voltage one is connected to the capacitors EC4 and C4 and the resistor R8 in parallel, and the other ends of the capacitors EC4 and C4 and the resistor R8 are grounded.

5. The low power consumption variable frequency washing machine control system according to claim 1, wherein, The output module comprises an output unit two, which outputs a 15V direct current voltage two and a 5V direct current voltage three. The output unit two includes a diode D2, a resistor R9, a capacitor C5, a capacitor EC5, a capacitor C6 and a resistor R10. The resistor R9 and the capacitor C5 are connected in series and connected to both ends of the diode D2, one end of the diode D2 is connected to the secondary winding of the transformer T1, and the other end outputs a direct current voltage two as an output terminal. The capacitor EC5, the capacitor C6 and the resistor R10 are connected in parallel and connected to the output terminal of the direct current voltage two, and the other ends of the capacitor EC5, the capacitor C6 and the resistor R10 are grounded.

6. The low power consumption variable frequency washing machine control system according to claim 5, wherein, The output unit two further includes a step-down converter U4 connected to the direct current voltage two, which converts the direct current voltage two into a direct current voltage three and outputs the direct current voltage three. The VIN pin of the step-down converter U4 is connected to the direct current voltage two, and the capacitor C8 and the capacitor C10 are connected in parallel to the VIN pin. The inductor L4 is directly connected to the VOUT pin and the SW pin of the step-down converter U4. The VOUT pin of the step-down converter U4 outputs the direct current voltage three as an output terminal. The capacitor C9, the capacitor C11 and the capacitor EC6 are connected in parallel to the VOUT pin of the step-down converter U4, and the other ends of the capacitor C9, the capacitor C11 and the capacitor EC6 are grounded.

7. The low power consumption variable frequency washing machine control system according to claim 1, wherein, The power supply circuit further includes a feedback module including a triode Q2, which is used to feed back the signal of the secondary winding of the transformer T1 to the power supply chip U2, so that the power supply chip U2 can adjust the duty cycle of the PWM signal according to the feedback signal.

8. The low power consumption variable frequency washing machine control system according to claim 1, wherein, The drive control board is further provided with a zero-crossing detection circuit, which includes a resistor R35, a resistor R34, a resistor R30, a resistor R31, a diode D30, a capacitor C30, a triode Q30, a resistor R32, a resistor R33 and a capacitor C31. The base of the triode Q30 is connected to the capacitor C30, the diode D30 and the resistor R31 in parallel. The other ends of the capacitor C30, the diode D30 and the resistor R31 are grounded. The resistor R31 is further connected to the resistor R30, the resistor R34 and the resistor R35 in series. The other end of the resistor R35 is connected to a detection point of the power supply circuit to input the AC_L' signal. The emitter of the triode Q30 is grounded. The collector of the triode Q30 is connected to the resistor R32. The other end of the resistor R32 is connected to a power supply voltage. The resistor R33 and the capacitor C31 are connected in series between the emitter and the collector of the triode Q30. The AC_INT signal between the resistor R33 and the capacitor C31 is input into the control board main control chip MCU.

9. The low power consumption variable frequency washing machine control system according to claim 1, wherein, The drive control board is further provided with a bus voltage detection circuit, which includes a resistor R80, a resistor R81, a resistor R82, a resistor R83, a resistor R84, a capacitor C80, a capacitor C81 and a diode D80. The resistance R80, the resistance R81, the resistance R82, the resistance R83 are connected in series, one end of the resistance R80 is connected with the detection point P of the power supply circuit; the resistance R82 and the resistance R83 are connected with the parallel resistance R84 and the capacitor C80, the other end of the resistance R84 and the capacitor C80 is grounded, the other end of the resistance R83 is connected with the parallel diode D80 and the capacitor C81, the other end of the capacitor C81 is grounded, the other end of the diode D80 is connected with the power supply voltage, the signal Vfb_bus between the diode D80, the capacitor C81 and the resistance R83 is connected with the main control chip MCU of the control panel.

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