A power supply for a domestic appliance

Abstract

The application relates to a household appliance power supply. The household appliance power supply comprises a power factor correction circuit and a flyback power supply circuit; the power factor correction circuit is used for adjusting a rectified voltage after bridge rectification into a bus input voltage; the power factor correction circuit comprises a power diode, a filter capacitor and a power factor correction switch tube; the flyback power supply circuit comprises a high-frequency transformer, a first rectifier diode, a second rectifier diode, a third rectifier diode, a first filter capacitor, a second filter capacitor and a third filter capacitor. The household appliance power supply provided by the application can save the power factor correction circuit inductance by combining the primary inductance of the high-frequency transformer and the power factor correction inductance, reduce the area of the PCB, and thus reduce the cost of the controller.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric appliance power supply, in particular to a household appliance power supply. BACKGROUND

[0002] The common household appliance power supply is a switching power supply, and the common topology of the switching power supply is a flyback power supply. The load capacity of the flyback power supply is generally tens of watts, and the common structure is to take power from the bus after power factor correction, and to realize low-voltage multi-output through the flyback topology of the power IC and the high-frequency transformer. With the progress of digital power supply technology, household appliance power supply needs to be more digital and smaller, thereby reducing hardware costs.

[0003] The existing household appliance power supply generally includes a power factor correction circuit and a flyback power supply circuit. The power factor correction circuit includes a power factor correction circuit inductor, and the flyback power supply circuit includes a high-frequency transformer. The high-frequency transformer has a primary inductor and inductors of various load circuits. The large number of inductors in the power supply circuit occupies a large PCB area, and the miniaturization of the household appliance power supply is needed. SUMMARY

[0004] To overcome the problems in the related art, the present application provides a household appliance power supply. The household appliance power supply can omit the analog power supply and the power factor correction circuit inductor, reduce the area of the PCB, and reduce the cost of the controller. The household appliance power supply can generate a PWM wave to turn on the power factor correction switch tube, reduce the loss of the current-limiting resistor in the self-oscillation circuit, and also reduce the loss of cutting off the output of the self-oscillation circuit. The present application also provides a bus voltage control circuit and method, which can stabilize the bus voltage at a set voltage.

[0005] A household appliance power supply includes:

[0006] a power factor correction circuit and a flyback power supply circuit;

[0007] The power factor correction circuit is configured to adjust a rectified voltage (VR) after bridge rectification to a bus input voltage (VP).

[0008] The power factor correction circuit includes a power diode (D1), a filter capacitor (C), and a power factor correction switch tube (Q).

[0009] The flyback power supply circuit includes a high-frequency transformer (T1), a first rectifier diode (D2), a second rectifier diode (D3), a third rectifier diode (D4), a first filter capacitor (C1), a second filter capacitor (C2), and a third filter capacitor (C3).

[0010] The flyback power supply circuit is used for connecting the power factor correction circuit, obtaining a load voltage through a high-frequency transformer from the rectified voltage (VR), and driving a load to operate through the load voltage;

[0011] The primary inductance (N1) of the high-frequency transformer is electrically connected to the drain of the power factor correction switch tube (Q), and the primary inductance (N1) of the high-frequency transformer is electrically connected to the anode of the power diode (D1); the first rectifier diode (D2) is connected in series with the first filter capacitor (C1), the second rectifier diode (D3) is connected in series with the second filter capacitor (C2), and the third rectifier diode (D4) is connected in series with the third filter capacitor (C3).

[0012] A household appliance power supply further comprises:

[0013] A self-oscillating circuit, which outputs a pulse width modulation (PWM) wave from the rectified voltage (VR) through self-oscillation;

[0014] The self-oscillating circuit comprises a current-limiting resistor (RZ), a triode (Q2), an operational amplifier (A), a charging capacitor (C), and a voltage stabilizing diode (DZ1);

[0015] The bus input end is grounded through the negative and positive electrodes of the current-limiting resistor (RZ) and the voltage stabilizing diode (DZ1) in sequence; the collector of the triode (Q2) is grounded through the current-limiting resistor (RZ), and the emitter of the triode (Q2) is grounded; the collector of the triode (Q2) is electrically connected to the non-inverting input end of the operational amplifier (A), and the inverting input end of the operational amplifier (A) is grounded through the charging capacitor (C).

[0016] A household appliance power supply further comprises:

[0017] A bus voltage control circuit, which is connected to a bus input voltage (VP) and the rectified voltage (VR) and outputs a set voltage to a motor coil;

[0018] The bus voltage control circuit comprises a relay (Q3), a bus voltage control fan (M), a first insulated gate bipolar transistor (IGBT) (1), a second insulated gate bipolar transistor (IGBT) (2), a third insulated gate bipolar transistor (IGBT) (3), a fourth insulated gate bipolar transistor (IGBT) (4), a fifth insulated gate bipolar transistor (IGBT) (5), and a sixth insulated gate bipolar transistor (IGBT) (6);

[0019] The relay (Q3) is electrically connected with the GPIO port of the single-chip microcomputer control unit, the collector of the IGBT (1) is electrically connected with the bus input end, the emitter of the IGBT (1) is electrically connected with the U end of the bus voltage control fan (M); the collector of the IGBT (2) is electrically connected with the U end of the bus voltage control fan (M), and the emitter of the IGBT (2) is grounded; the collector of the IGBT (3) is electrically connected with the bus input end, the emitter of the IGBT (3) is electrically connected with the V end of the bus voltage control fan (M); the collector of the IGBT (4) is electrically connected with the V end of the bus voltage control fan (M), and the emitter of the IGBT (4) is grounded; the collector of the IGBT (5) is electrically connected with the bus input end, the emitter of the IGBT (5) is electrically connected with the W end of the bus voltage control fan (M); and the collector of the IGBT (6) is electrically connected with the W end of the bus voltage control fan (M), and the emitter of the IGBT (6) is grounded.

[0020] The control flow of the bus voltage control circuit is as follows:

[0021] The relay (Q3) of the bus voltage control circuit is turned on after a delay;

[0022] The first IGBT, the second IGBT, the third IGBT, the fourth IGBT, the fifth IGBT and the sixth IGBT in the bus voltage control circuit are provided with intermittent pulses, so that the bus driving fan does not rotate, and the motor coil is connected to the load;

[0023] The single-cycle control algorithm is used to stabilize the bus voltage at the set voltage;

[0024] The first IGBT, the second IGBT, the third IGBT, the fourth IGBT, the fifth IGBT and the sixth IGBT in the bus control circuit are provided with running pulses, so that the bus driving fan rotates, and the motor coil is connected to the load.

[0025] A household appliance power supply further comprises:

[0026] A single-chip microcomputer control unit outputs pulse control signals to the first IGBT, the second IGBT, the third IGBT, the fourth IGBT, the fifth IGBT and the sixth IGBT in the bus voltage control circuit according to the bus input voltage (VP);

[0027] The single-chip microcomputer control unit outputs control signals to the relay (Q3) in the bus voltage control circuit according to the bus input voltage (VP);

[0028] The single-chip microcomputer control unit outputs a control signal to a triode (Q2) in the self-oscillation circuit according to the conduction state of the power factor correction switch tube (Q).

[0029] The single-chip microcomputer control unit outputs a control signal to the power factor correction switch tube (Q) after the power factor correction switch tube (Q) is turned on.

[0030] The single-chip microcomputer control unit and the load in the flyback power supply circuit are connected, and the single-chip microcomputer control unit controls the load 1 to operate after the first rectifier diode (D2) is turned on, controls the load 2 to operate after the second rectifier diode (D3) is turned on, and controls the load 3 to operate after the third rectifier diode (D4) is turned on.

[0031] The self-oscillation circuit can adjust the period and duty cycle of the PWM wave:

[0032] The specific calculation formula of the PWM wave period is as follows:

[0033]

[0034] The specific calculation formula of the PWM wave duty cycle is as follows:

[0035]

[0036] Among them, RW1 is a charging resistor, RW2 is a discharging resistor, R3 is an operational amplifier reverse terminal resistor, R1 is a first voltage dividing resistor, R2 is a second voltage dividing resistor, and C is a charging capacitor.

[0037] The single-chip microcomputer control unit outputs a control signal to a triode (Q2) in the self-oscillation circuit according to the conduction state of the power factor correction switch tube (Q).

[0038] The single-chip microcomputer control unit outputs a high level to the base of the triode (Q2) in the self-oscillation circuit, cuts off the input of the non-inverting terminal of the operational amplifier (A), and stops the self-oscillation circuit from generating the PWM wave.

[0039] The single-chip microcomputer control unit is powered on after the power factor correction switch tube (Q) is turned on.

[0040] When the PWM wave is stopped, the single-chip microcomputer control unit controls the power factor correction switch tube (Q) to be in a conduction state.

[0041] The drain of the power factor correction switch tube (Q) is sequentially connected to the positive and negative electrodes of the power diode (D1) and the ground of the filter capacitor (C), and the source of the power factor correction switch tube (Q) is grounded.

[0042] The technical scheme provided in the application can have the following beneficial effects:

[0043] The household appliance power supply provided by the application comprises a power factor correction circuit and a flyback power supply circuit, the power factor correction switch tube can realize the function of switching DC voltage boost, the primary side inductance of the high-frequency transformer is electrically connected to the drain of the power factor correction switch tube, and the primary side inductance of the high-frequency transformer is electrically connected to the anode of the power diode; the first rectifier diode is connected in series with the first filter capacitor, the second rectifier diode is connected in series with the second filter capacitor, and the third rectifier diode is connected in series with the third filter capacitor, and the flyback power supply circuit can realize the function of reducing voltage and driving the load to operate. In the connection relationship of the two groups of circuits, the primary side inductance of the high-frequency transformer and the power factor correction circuit inductance are combined in the application, the power factor correction circuit inductance can be saved, the area of the PCB is reduced, and the cost of the household appliance power supply is reduced.

[0044] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory and are not restrictive of the application. BRIEF DESCRIPTION OF DRAWINGS

[0045] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the several views.

[0046] Figure 1 is a power factor correction circuit and a flyback power supply circuit schematic diagram shown by an embodiment of the application;

[0047] Figure 2 is a self-oscillation circuit schematic diagram shown by an embodiment of the application;

[0048] Figure 3 is a bus voltage control circuit schematic diagram shown by an embodiment of the application;

[0049] Figure 4 is a bus voltage control method schematic diagram shown by an embodiment of the application. DETAILED DESCRIPTION

[0050] The preferred embodiments of the application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the application are shown in the drawings, it should be understood that the application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the application more thorough and complete, and to fully convey the scope of the application to those skilled in the art.

[0051] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term "and / or," as used herein, refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0052] It should be understood that although the terms "first," "second," "third," etc. can be used herein to describe various information, the information should not be limited by these terms. These terms are only used to distinguish one piece of information from another. For example, a first information can also be termed a second information, and, similarly, a second information can also be termed a first information, without departing from the scope of the present application. Therefore, the features defined with "first," "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically defined.

[0053] The commonly used power supply of the electric appliance cannot output PWM wave to control the working state of the power supply when the single-chip microcomputer control unit is not powered on at the start. After the single-chip microcomputer control unit establishes stable power supply, the self-excitation output end is cut off from the self-excitation oscillation circuit output, causing great power loss.

[0054] In view of the above problems, the present application provides a household appliance power supply, please refer to Figure 1 , Figure 1 is a power factor correction circuit and flyback power supply circuit schematic diagram shown in an embodiment of the present application.

[0055] Embodiment one

[0056] A household appliance power supply includes:

[0057] A power factor correction circuit and a flyback power supply circuit.

[0058] The power factor correction circuit is used to connect the bus input end, and adjust the rectified voltage VR after bridge rectification to the bus input voltage VP. The power factor correction circuit includes a bridge rectification circuit for bridge rectification, which is not shown in the figure. Figure 1

[0059] The power factor correction circuit includes a power diode D1, a filter capacitor C and a power factor correction switch tube Q.

[0060] The drain of the power factor correction switch tube Q is connected to the positive and negative electrodes of the power diode D1 and the ground of the filter capacitor C in sequence, and the source of the power factor correction switch tube Q is grounded. ​

[0061] The power factor correction switch tube Q is turned on, and the rectified voltage VR is changed from a direct current voltage to an alternating current voltage. The single-chip microcomputer control unit is powered on after the power factor correction switch tube Q is turned on, and outputs a control signal to the power factor correction switch tube Q;

[0062] The flyback power supply circuit includes a high-frequency transformer T1, a first rectifier diode D2, a second rectifier diode D3, a third rectifier diode D4, a first filter capacitor C1, a second filter capacitor C2, and a third filter capacitor C3.

[0063] The flyback power supply circuit is used to connect the power factor correction circuit, so that the rectified voltage VR is obtained through the high-frequency transformer to obtain a load voltage, and the load is driven to operate through the load voltage.

[0064] The primary inductance N1 of the high-frequency transformer is electrically connected to the drain of the power factor correction switch tube Q, and the primary inductance N1 of the high-frequency transformer is electrically connected to the anode of the power diode D1; the first rectifier diode D2 is connected in series with the first filter capacitor C1, the second rectifier diode D3 is connected in series with the second filter capacitor C2, and the third rectifier diode D4 is connected in series with the third filter capacitor C3.

[0065] D1, D2, and D3 are rectifier diodes, and C1, C2, and C3 are filter capacitors. When the voltage of the rectifier diode is greater than or equal to a threshold value, the single-chip microcomputer control unit controls the load 1, the load 2, and the load 3 to operate.

[0066] The household appliance power supply provided by the embodiment of the application includes a power factor correction circuit and a flyback power supply circuit. The power factor correction switch tube can realize the function of switching direct current voltage to boost voltage. The primary inductance of the high-frequency transformer is electrically connected to the drain of the power factor correction switch tube, and the primary inductance of the high-frequency transformer is electrically connected to the anode of the power diode. The first rectifier diode is connected in series with the first filter capacitor, the second rectifier diode is connected in series with the second filter capacitor, and the third rectifier diode is connected in series with the third filter capacitor. Through the flyback power supply circuit, the function of reducing voltage and driving the load to operate can be realized. In the connection relationship of the two groups of circuits, the primary inductance of the high-frequency transformer and the inductance of the power factor correction circuit are combined in the embodiment of the application, so that the inductance of the power factor correction circuit can be omitted, the area of the PCB is reduced, and the cost of the household appliance power supply is reduced.

[0067] Embodiment two

[0068] The single-chip microcomputer control unit cannot be powered immediately after the starting of the commonly used household appliance power supply, and there is a blank period for waiting for power on, during which the load cannot be driven to work. After the single-chip microcomputer control unit establishes stable power supply, the prior art generally cuts off the output of the self-oscillation circuit at the self-oscillation output end, which causes great power loss.

[0069] Figure 2 is a self-oscillation circuit schematic diagram shown in the embodiment of the present application.

[0070] Please refer to Figure 2 , the input of the self-oscillation circuit is a rectified voltage VR, which is output as a PWM wave through self-oscillation of the power factor correction switch tube.

[0071] The self-oscillation circuit comprises a current-limiting resistor RZ, a triode Q2, an operational amplifier A and a stabilizing diode DZ1, a charging resistor RW1, a discharging resistor RW2, an operational amplifier reverse end resistor R3, a first voltage-dividing resistor R1, a second voltage-dividing resistor R2 and a charging capacitor C.

[0072] The bus input end is grounded through the negative and positive poles of the current-limiting resistor RZ and the stabilizing diode DZ1 in sequence; the collector of the triode Q2 is grounded through the current-limiting resistor RZ, and the emitter of the triode Q2 is grounded; the collector of the triode Q2 is electrically connected to the non-inverting input end of the operational amplifier A, and the reverse input end of the operational amplifier A is grounded through the charging capacitor C.

[0073] The rectified voltage VR is the voltage before the primary inductor N1 of the high-frequency transformer after bridge rectification, and the rectified voltage VR is generally about 310V, and the bus input voltage VP is generally set to 380V, so that the rectified voltage VR is lower than the bus input voltage VP, which is conducive to reducing the power consumption at the current-limiting resistor RZ.

[0074] DZ1 is a stabilizing diode, and the selected voltage value of DZ1 is not higher than the voltage value of the power supply of the operational amplifier.

[0075] When the charge of the charging capacitor C is low, the voltage at the non-inverting input end of the operational amplifier is higher than the voltage at the reverse input end of the operational amplifier, at which time the output voltage U O of the operational amplifier DZ1 = +V O The charging capacitor C is positively charged through RW1, D1 and R3, and the time constant is

[0076] τ1 = (RW1 + R3)C;

[0077] When the charge capacitor C has a high amount of electricity, the voltage at the non-inverting input of the operational amplifier is lower than the voltage at the inverting input of the operational amplifier, at which time the output voltage U O = -V DZ1 , U O The charge capacitor C is discharged through RW2, D2 and R3, and the equivalent resistance when the diode is turned on is ignored, so the time constant is

[0078] τ2 = (RW2 + R3)C

[0079] Using the three-element method of the first-order RC circuit, the period and duty cycle can be solved:

[0080]

[0081]

[0082] where T is the period and q is the duty cycle, and the period and duty cycle can be adjusted by adjusting RW1, RW2, R3 and C. For example, increasing the charge capacitor C and increasing the discharge resistance RW2 can increase the duty cycle q while increasing the period T.

[0083] By alternately charging and discharging the charge capacitor C, the output voltage of the operational amplifier is switched back and forth between +V DZ1 and -V DZ1 , thereby outputting a PWM wave to the power factor correction switch tube.

[0084] The transistor Q2 in the self-oscillating circuit is connected to ground via the resistor R1, and the transistor Q2 is electrically connected to the resistor R2, and the base of the transistor is controlled by the GPIO port of the single-chip microcomputer control unit.

[0085] When the single-chip microcomputer control unit is powered stably, the output of the self-oscillating circuit can be cut off. By outputting a high level to the base of the transistor Q2 in the self-oscillating circuit through the GPIO port of the single-chip microcomputer control unit, the input of the operational amplifier is cut off, so that the self-oscillating circuit stops generating a PWM wave. The output of the self-oscillating circuit is about +5V, while the voltage at the non-inverting input of the operational amplifier is less than +1V. Compared with cutting off the output of the self-oscillating circuit, cutting off the input of the operational amplifier can effectively reduce the loss on the current limiting resistor RZ.

[0086] The embodiment of the application provides a self-excited oscillation circuit, which is connected with a bus input end to ground via a current-limiting resistor and a negative electrode and a positive electrode of a voltage stabilizing diode in sequence; a collector of a triode is connected to ground via the current-limiting resistor, and an emitter of the triode is connected to ground; the collector of the triode is electrically connected to a non-inverting input end of an operational amplifier, and an inverting input end of the operational amplifier is connected to ground via a charging capacitor. The self-excited oscillation circuit can generate a PWM wave to make a power factor correction switch tube conduct, can reduce the loss of the current-limiting resistor in the self-excited oscillation circuit by using a voltage after a rectifier bridge as input, and can reduce the loss of cutting off the output of the self-excited oscillation circuit by cutting off the input of the non-inverting input end of the operational amplifier.

[0087] Embodiment three

[0088] When the single-chip microcomputer control unit is not powered on, the load connected to the bus cannot work, at this time, the IGBT can make the bus voltage continuously rise, a temporary load needs to be connected to stabilize the bus voltage, and the temporary load is replaced by the load needing to be driven after the bus voltage is stabilized.

[0089] The embodiment of the application provides a bus voltage control circuit and a control method, Figure 3 It is a bus voltage control circuit schematic diagram shown by the embodiment of the application.

[0090] Please refer to Figure 3 The bus voltage control circuit comprises a relay Q3, a bus voltage control fan M, a first insulated gate bipolar transistor IGBT1, a second insulated gate bipolar transistor IGBT2, a third insulated gate bipolar transistor IGBT3, a fourth insulated gate bipolar transistor IGBT4, a fifth insulated gate bipolar transistor IGBT5 and a sixth insulated gate bipolar transistor IGBT6.

[0091] The relay Q3 is electrically connected with the GPIO port of the single-chip microcomputer control unit, the collector of the IGBT1 is electrically connected with the bus input end, the emitter of the IGBT1 is electrically connected with the U terminal of the bus voltage control fan M; the collector of the IGBT2 is electrically connected with the U terminal of the bus voltage control fan M, and the emitter of the IGBT2 is grounded; the collector of the IGBT3 is electrically connected with the bus input end, the emitter of the IGBT3 is electrically connected with the V terminal of the bus voltage control fan M; the collector of the IGBT4 is electrically connected with the V terminal of the bus voltage control fan M, and the emitter of the IGBT4 is grounded; the collector of the IGBT5 is electrically connected with the bus input end, the emitter of the IGBT5 is electrically connected with the W terminal of the bus voltage control fan M; the collector of the IGBT6 is electrically connected with the W terminal of the bus voltage control fan M, and the emitter of the IGBT6 is grounded. The U terminal of the control fan M is a first fan wiring terminal, the V terminal of the control fan M is a second fan wiring terminal, and the W terminal of the control fan M is a third fan wiring terminal.

[0092] The bus voltage control circuit inputs the bus input voltage VP and the rectified voltage VR, and outputs the bus input voltage VP to the motor coil. After the bus input voltage VP is stabilized at the set voltage, the bus voltage control fan M is outputted with the set voltage.

[0093] Figure 4 It is a bus voltage control method diagram shown in the embodiment of the application.

[0094] Please refer to Figure 4 A bus voltage control method, comprising:

[0095] A1, delay opening the relay Q3 of the bus voltage control circuit.

[0096] After the bus input voltage VP is inputted, the relay of the bus voltage control circuit is in the off state by using the GPIO port of the single-chip microcomputer control unit.

[0097] A2, all IGBTs in the bus voltage control circuit are provided with intermittent pulses, so that the bus driving fan does not rotate, and the motor coil is connected to the load.

[0098] The IGBT is a switch tube, and by providing intermittent pulses to the IGBT, the IGBT can be kept in the off state.

[0099] The single-chip microcomputer control unit provides intermittent pulses to all IGBTs, which can switch the load circuit to the second load circuit, so that the bus driving fan does not rotate, and the motor coil is connected to the load. The motor coil has an order of magnitude of tens of ohms, which is used to consume power and prevent the bus voltage from continuously rising.

[0100] A3, using a single cycle control algorithm to stabilize the bus voltage at a set voltage.

[0101] A4, providing running pulses to all IGBTs in the bus voltage control circuit, making the bus drive fan rotate, and connecting the motor coil out of the load.

[0102] The single-chip microcomputer control unit provides running pulses to all IGBTs in the bus voltage control circuit, can switch the load circuit to the first load circuit, so that the load becomes the bus drive motor, and the motor coil is connected out of the load.

[0103] The bus voltage control circuit and method provided by the embodiments of the present application can provide intermittent pulses to all IGBTs in the bus voltage control circuit by delaying the opening of the relay of the bus voltage control circuit, so that the bus drive fan does not rotate, and the motor coil is connected to the load. Using a single cycle control algorithm to stabilize the bus voltage at a set voltage, so that the bus voltage does not continuously rise when the single-chip microcomputer control unit is not powered on. Then, the motor coil is connected out of the load, running pulses are provided to all IGBTs in the bus voltage control circuit, the bus drive fan is made to rotate, and the bus drive fan can operate under stable bus voltage.

[0104] The solutions of the present application have been described in detail above with reference to the accompanying drawings. In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments. Those skilled in the art should also know that the actions and modules involved in the specification are not necessarily required by the present application. In addition, it can be understood that the steps in the method embodiments of the present application can be adjusted, combined and reduced in sequence according to actual needs, and the modules in the device embodiments of the present application can be combined, divided and reduced according to actual needs.

[0105] Those skilled in the art will also appreciate that the various example logical blocks, modules, circuits, and algorithm steps described in connection with the present application herein can be implemented as electronic hardware, computer software, or a combination of the two.

[0106] The computer software can be coded using any suitable machine code or computer language that can be subject to well- defined and repetitive processing. Note that the computer software can be written in an interpreted language or can be written in a compiled language that is converted into a computer independent intermediate representation code or object code suitable for usage on a variety of computers (i.e., different machines) or that is converted into a proprietary

[0107] Embodiments of the present application have been described above, with the understanding that these embodiments are exemplary only, and not exhaustive, and are not limited to the embodiments disclosed. Many modifications and variations of the described embodiments are possible, without departing from the scope and spirit of the described embodiments. The selection of terms to be used in the description is intended to best explain the principles of the embodiments, practical application, or improvement over the technology in the art, or to enable other ordinary skilled in the art to understand the embodiments disclosed herein.

Claims

1. A power supply for a domestic appliance, characterized in that, Comprise: Power factor correction circuit and flyback power supply circuit; The power factor correction circuit is used to adjust the bridge rectified rectified voltage (VR) to bus input voltage (VP); The power factor correction circuit comprises: power diode (D1), filter capacitor (C) and power factor correction switch tube (Q); The drain of the power factor correction switch tube (Q) is grounded via the anode and cathode of the power diode (D1) and the filter capacitor (C) in turn, and the source of the power factor correction switch tube (Q) is grounded; The flyback power supply circuit comprises: high-frequency transformer (T1), first rectifier diode (D2), second rectifier diode (D3), third rectifier diode (D4), first filter capacitor (C1), second filter capacitor (C2) and third filter capacitor (C3); The flyback power supply circuit is used to connect the power factor correction circuit, obtain the load voltage through the high-frequency transformer from the rectified voltage (VR), and drive the load to run through the load voltage; One end of the primary inductance (N1) of the high-frequency transformer is connected to the rectified voltage (VR), the other end of the primary inductance (N1) of the high-frequency transformer is electrically connected to the drain of the power factor correction switch tube (Q), and the other end of the primary inductance (N1) of the high-frequency transformer is electrically connected to the anode of the power diode (D1); the first rectifier diode (D2) is connected in series with the first filter capacitor (C1), the second rectifier diode (D3) is connected in series with the second filter capacitor (C2), and the third rectifier diode (D4) is connected in series with the third filter capacitor (C3); The first secondary inductance (N2) of the high-frequency transformer is connected to load 1 through the first rectifier diode (D2), the second secondary inductance (N3) of the high-frequency transformer is connected to load 2 through the second rectifier diode (D3), and the third secondary inductance (N4) of the high-frequency transformer is connected to load 3 through the third rectifier diode (D4); The power supply of the household appliance further comprises: Self-oscillation circuit, the self-oscillation circuit outputs pulse width modulation PWM wave from the rectified voltage (VR) through self-oscillation; The self-oscillation circuit comprises: current limiting resistor (RZ), transistor (Q2), operational amplifier (A), charging capacitor (C), voltage stabilizing diode (DZ1), charging resistor (RW1), discharging resistor (RW2), operational amplifier inverting terminal resistor (R3), first voltage dividing resistor (R1), second voltage dividing resistor (R2), first diode (D1) and second diode (D2); The rectified voltage (VR) is grounded via the current limiting resistor (RZ) and the negative and positive electrodes of the voltage stabilizing diode (DZ1) in turn; the collector of the transistor (Q2) is grounded via the voltage stabilizing diode (DZ1), and the emitter of the transistor (Q2) is grounded; the collector of the transistor (Q2) is electrically connected to the non-inverting input terminal of the operational amplifier (A), and the inverting input terminal of the operational amplifier (A) is grounded via the charging capacitor (C); The collector of the triode (Q2) is grounded via the first voltage dividing resistor (R1), and the output of the operational amplifier (A) is connected via the second voltage dividing resistor (R2), the inverting input of the operational amplifier (A) is connected to the negative electrode of the first diode (D1) and the positive electrode of the second diode (D2) via the operational amplifier inverting terminal resistor (R3), the positive electrode of the first diode (D1) is connected to the output of the operational amplifier (A) via the charging resistor (RW1), and the negative electrode of the second diode (D2) is connected to the output of the operational amplifier (A) via the discharging resistor (RW2).

2. A power supply for a domestic appliance according to claim 1, characterised in that, Further comprising: A bus voltage control circuit, the bus voltage control circuit is connected to the bus input voltage (VP) and the rectified voltage (VR), and outputs a set voltage to the motor coil; The bus voltage control circuit comprises: a relay (Q3), a bus voltage control fan (M), a first insulated gate bipolar transistor IGBT (1), a second insulated gate bipolar transistor IGBT (2), a third insulated gate bipolar transistor IGBT (3), a fourth insulated gate bipolar transistor IGBT (4), a fifth insulated gate bipolar transistor IGBT (5) and a sixth insulated gate bipolar transistor IGBT (6); The relay (Q3) is electrically connected to the GPIO port of the single-chip microcomputer control unit, the collector of the first insulated gate bipolar transistor IGBT (1) is electrically connected to the bus input voltage (VP), and the emitter of the first insulated gate bipolar transistor IGBT (1) is electrically connected to the U terminal of the bus voltage control fan (M); the collector of the second insulated gate bipolar transistor IGBT (2) is electrically connected to the U terminal of the bus voltage control fan (M), and the emitter of the second insulated gate bipolar transistor IGBT (2) is grounded; the collector of the third insulated gate bipolar transistor IGBT (3) is electrically connected to the bus input voltage (VP), and the emitter of the third insulated gate bipolar transistor IGBT (3) is electrically connected to the V terminal of the bus voltage control fan (M); the collector of the fourth insulated gate bipolar transistor IGBT (4) is electrically connected to the V terminal of the bus voltage control fan (M), and the emitter of the fourth insulated gate bipolar transistor IGBT (4) is grounded; the collector of the fifth insulated gate bipolar transistor IGBT (5) is electrically connected to the bus input voltage (VP), and the emitter of the fifth insulated gate bipolar transistor IGBT (5) is electrically connected to the W terminal of the bus voltage control fan (M); the collector of the sixth insulated gate bipolar transistor IGBT (6) is electrically connected to the W terminal of the bus voltage control fan (M), and the emitter of the sixth insulated gate bipolar transistor IGBT (6) is grounded.

3. A power supply for a domestic appliance according to claim 2, characterised in that, The control flow of the bus voltage control circuit is: The relay (Q3) of the bus voltage control circuit is turned on with a delay; Providing intermittent pulses to the first, second, third, fourth, fifth and sixth insulated gate bipolar transistors (IGBTs) in the bus voltage control circuit to stop the bus driving fan from rotating and connect the motor coil to the load; Using a single cycle control algorithm to stabilize the bus voltage at a set voltage; Providing running pulses to the first, second, third, fourth, fifth and sixth insulated gate bipolar transistors (IGBTs) in the bus voltage control circuit to make the bus driving fan rotate and disconnect the motor coil from the load.

4. A power supply for a domestic appliance according to claim 2, characterised in that, Further comprising: A single-chip microcomputer control unit that outputs pulse control signals to the first, second, third, fourth, fifth and sixth insulated gate bipolar transistors (IGBTs) in the bus voltage control circuit according to the bus input voltage (VP); The single-chip microcomputer control unit outputs control signals to the relay (Q3) in the bus voltage control circuit according to the bus input voltage (VP); The single-chip microcomputer control unit outputs control signals to the triode (Q2) in the self-oscillation circuit according to the conduction of the power factor correction switch tube (Q); The single-chip microcomputer control unit outputs control signals to the power factor correction switch tube (Q) after it is turned on; The single-chip microcomputer control unit and the load in the flyback power supply circuit are connected, and the load 1 is controlled to operate after the first rectifier diode (D2) is turned on, the load 2 is controlled to operate after the second rectifier diode (D3) is turned on, and the load 3 is controlled to operate after the third rectifier diode (D4) is turned on.

5. A power supply for a domestic appliance according to claim 1, characterized in that, The self-oscillation circuit can adjust the period and duty cycle of the PWM wave: The specific calculation formula of the PWM wave period is as follows: ； The specific calculation formula of the PWM wave duty cycle is as follows: ； Where RW1 is the charging resistance, RW2 is the discharging resistance, R3 is the reverse terminal resistance of the operational amplifier, R1 is the first voltage dividing resistance, R2 is the second voltage dividing resistance, and C is the charging capacitor.

6. A power supply for a domestic appliance according to claim 4, characterised in that, The output of control signals to the triode (Q2) in the self-oscillation circuit includes: The single-chip microcomputer control unit outputs high level to the base of the triode (Q2) in the self-oscillation circuit, cuts off the input of the non-inverting terminal of the operational amplifier (A), and makes the self-oscillation circuit stop generating PWM wave.

7. A power supply for a domestic appliance according to claim 4, characterised in that, The single-chip microcomputer control unit is powered on after the power factor correction switch tube (Q) is turned on.

8. A power supply for a domestic appliance according to claim 6, characterised in that, When the generation of the PWM wave is stopped, the single-chip microcomputer control unit controls the power factor correction switch tube (Q) to be in the on state.

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