Motor driving circuit and household appliance

Abstract

The utility model discloses a motor driving circuit and a household appliance. The motor driving circuit comprises a power supply branch, a first signal processing branch, an amplification branch, a controller and a motor control branch. The power supply branch is configured to output a power supply for supplying power to the motor based on the first alternating current power supply so as to supply power to the motor, and the power supply branch comprises a first capacitor connected with the motor in parallel. The first signal processing branch is configured to perform current limiting and filtering on the first alternating current power supply and then output the first alternating current power supply. The amplification branch is configured to amplify the current-limited and filtered first alternating current power supply and then output a second alternating current power supply greater than zero. The controller is configured to output a control signal in response to the fact that the voltage of the second alternating current power supply is larger than a first preset voltage threshold value or smaller than a second preset voltage threshold value, and the first preset voltage threshold value is larger than the second preset voltage threshold value. The motor control branch is configured to respond to the control signal and control the motor to operate. Through the mode, the first capacitor with relatively low capacity can be adopted, so that the cost is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of electronic circuit technology, and in particular to a motor drive circuit and a household appliance. Background Art

[0002] Motors are usually installed in large household appliances such as refrigerators and washing machines. The power supply of the motor is obtained from an AC power supply. The power supply end of the motor usually needs to be connected in parallel with an electrolytic capacitor for filtering. During the operation of the motor, there is a process in which the AC power supply gradually decreases. In this case, the electrolytic capacitor connected in parallel with the motor needs to be set to a large-capacity high-voltage aluminum electrolytic capacitor so that the electrolytic capacitor can also play the role of energy storage, thereby providing sufficient voltage to the motor to ensure the normal operation of the motor.

[0003] However, large-capacity, high-voltage aluminum electrolytic capacitors are expensive, resulting in high costs. Utility Model Content

[0004] The embodiments of the present application provide a motor drive circuit and a household appliance, which can use a first capacitor with a lower capacity to reduce costs.

[0005] In a first aspect, an embodiment of the present application provides a motor drive circuit, comprising:

[0006] a power supply branch connected to the motor and the first AC power source, and configured to supply power to the motor based on the output of the first AC power source, wherein the power supply branch includes a first capacitor connected in parallel with the motor;

[0007] A first signal processing branch, connected to the first AC power source, configured to perform current limiting and filtering on the first AC power source before outputting;

[0008] an amplifying branch, connected to the first signal processing branch, and configured to amplify the first AC power after current limiting and filtering and output a second AC power greater than zero;

[0009] a controller connected to the amplifying branch, and configured to output a control signal in response to the voltage of the second AC power source being greater than a first preset voltage threshold or less than a second preset voltage threshold, wherein the first preset voltage threshold is greater than the second preset voltage threshold;

[0010] The motor control branch is connected between the controller and the motor, and is configured to control the operation of the motor in response to the control signal.

[0011] In one or more embodiments, the motor drive circuit further includes a second signal processing branch;

[0012] The second signal processing branch is connected between the amplifying branch and the controller, and the second signal processing branch is configured to limit and filter the second AC power supply and then output it to the controller.

[0013] In one or more embodiments, the power supply branch further includes a rectifier unit;

[0014] The first AC power source is rectified by the rectifier unit and filtered by the first capacitor to supply power to the motor.

[0015] In one or more embodiments, the rectifier unit includes a rectifier bridge;

[0016] The first end of the rectifier bridge is connected to the first end of the first AC power supply, the second end of the rectifier bridge is connected to the second end of the first AC power supply, the third end of the rectifier bridge is connected to the first end of the first capacitor and the first end of the motor, and the fourth end of the rectifier bridge, the second end of the first capacitor and the second end of the motor are all grounded.

[0017] In one or more embodiments, the first signal processing branch includes a first resistor, a second resistor and a second capacitor;

[0018] The first resistor, the second capacitor and the second resistor are connected in series between the first end and the second end of the first AC power supply, the connection point between the first resistor and the second capacitor is connected to the first end of the amplifying branch, and the connection point between the second capacitor and the second resistor is connected to the second end of the amplifying branch.

[0019] In one or more embodiments, the amplifying branch includes a first operational amplifier, a first diode, a second diode, a third resistor, a fourth resistor, and a fifth resistor;

[0020] The anode of the first diode and the cathode of the second diode are both connected to the non-inverting input terminal of the first operational amplifier, the cathode of the first diode and the anode of the second diode are both connected to the inverting input terminal of the first operational amplifier, the third resistor and the fourth resistor are connected in series between the first power supply and the ground, the connection point between the third resistor and the fourth resistor is connected to the non-inverting input terminal of the first operational amplifier, and the fifth resistor is connected between the inverting input terminal and the output terminal of the first operational amplifier;

[0021] The inverting input terminal of the first operational amplifier is the first terminal of the amplifying branch, the non-inverting input terminal of the first operational amplifier is the second terminal of the amplifying branch, and the output terminal of the first operational amplifier is the third terminal of the amplifying branch.

[0022] In one or more embodiments, the second signal processing branch includes a sixth resistor and a third capacitor;

[0023] The sixth resistor and the third capacitor are connected in series between the output end of the amplifying branch and the ground, and the connection point between the sixth resistor and the third capacitor is connected to the controller.

[0024] In a second aspect, an embodiment of the present application provides a household appliance, comprising a motor and the motor drive circuit as described above, wherein the motor drive circuit is connected to the motor.

[0025] The beneficial effects of the present application are as follows: the motor drive circuit of the embodiment of the present application includes a power supply branch, a first signal processing branch, an amplification branch, a controller and a motor control branch. The power supply branch is configured to output a power supply for powering the motor based on the first AC power supply output, so as to power the motor, wherein the power supply branch includes a first capacitor connected in parallel with the motor. The first signal processing branch is configured to output the first AC power supply after current limiting and filtering. The amplification branch is configured to amplify the first AC power supply after current limiting and filtering and output a second AC power supply greater than zero. The controller is configured to output a control signal in response to the voltage of the second AC power supply being greater than a first preset voltage threshold or less than a second preset voltage threshold, wherein the first preset voltage threshold is greater than the second preset voltage threshold. The motor control branch is configured to control the operation of the motor in response to the control signal. Through the above method, the motor will only run during the time period when the voltage of the second AC power supply is greater than the first preset voltage threshold or less than the second preset voltage threshold, and the time period when the voltage of the second AC power supply is greater than the first preset voltage threshold can correspond to the time period when the voltage of the first AC power supply is greater than the third preset voltage threshold when the first AC power supply is in the positive half cycle, and the time period when the voltage of the second AC power supply is less than the second preset voltage threshold can correspond to the time period when the voltage of the first AC power supply is less than the fourth preset voltage threshold when the first AC power supply is in the negative half cycle. The third preset voltage threshold is determined by the first preset voltage threshold and the amplified value of the amplification branch, and the fourth preset voltage threshold is determined by the second preset voltage threshold and the amplified value of the amplification branch. It can be seen from this that the motor will only run when the absolute value of the voltage of the first AC power supply is large. At this time, the voltage of the first AC power supply can meet the power supply demand of the motor, then the first capacitor only needs to play a filtering role, and no longer needs to play a role in energy storage, so that a first capacitor with a lower capacity can be used to reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] One or more embodiments are exemplarily described by the figures in the corresponding drawings, and these exemplary descriptions are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0027] Figure 1The structure of the motor drive circuit provided in the embodiment of the present application is shown in FIG. Figure 1 ;

[0028] Figure 2 is a schematic diagram of a first AC power source and a second AC power source provided in an embodiment of the present application;

[0029] Figure 3 The structure of the motor drive circuit provided in the embodiment of the present application is shown in FIG. Figure 2 ;

[0030] Figure 4 The structure of the motor drive circuit provided in the embodiment of the present application is shown in FIG. Figure 3 ;

[0031] Figure 5 is with Figure 4 Schematic diagram of circuit structure corresponding to the structure shown. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] It should be noted that, when an element is described as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may exist therebetween.

[0034] In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no structural conflict between them.

[0035] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of the motor drive circuit provided in the embodiment of the present application. Figure 1 As shown, the motor driving circuit 100 includes a power supply branch 10, a first signal processing branch 20, an amplifying branch 30, a controller 40 and a motor control branch 50. The power supply branch 10 includes a first capacitor C1 connected in parallel with the motor 300.

[0036] The power supply branch 10 is connected to the motor 300 and the first AC power supply 200, specifically, the first end of the power supply branch 10 is connected to the first end of the first AC power supply 200, the second end of the power supply branch 10 is connected to the second end of the first AC power supply 200, and the first capacitor C1 in the power supply branch 10 is connected in parallel with the motor 300. The first signal processing branch 20 is connected to the first AC power supply 200, specifically, the first end of the first signal processing branch 20 is connected to the first end of the first AC power supply 200, and the second end of the first signal processing branch 20 is connected to the second end of the first AC power supply 200. The amplification branch 30 is connected to the first signal processing branch 20. The controller 40 is connected to the amplification branch 30. The motor control branch 50 is connected between the controller 40 and the motor 300. In some embodiments, the first AC power supply 200 is configured as a mains power supply (i.e., industrial frequency AC power).

[0037] Specifically, the power supply branch 10 is configured to output a power supply for the motor 300 based on the first AC power supply 200 to power the motor 300. The first signal processing branch 20 is configured to limit the current and filter the first AC power supply 200 before outputting it. The amplification branch 30 is configured to amplify the first AC power supply 200 after current limiting and filtering and output a second AC power supply greater than zero. The controller 40 is configured to output a control signal in response to the voltage of the second AC power supply being greater than a first preset voltage threshold or less than a second preset voltage threshold. The first preset voltage threshold is greater than the second preset voltage threshold, and both the first preset voltage threshold and the second preset voltage threshold are greater than 0. The motor control branch 50 is configured to control the operation of the motor 300 in response to the control signal. In a specific embodiment, the motor control branch 50 is configured to generate a start signal of the motor 300 in response to the control signal to control the operation of the motor 300; conversely, the motor control branch 50 is also configured to stop generating the start signal of the motor 300 when the control signal is not received to control the motor 300 to stop running. Among them, the first preset voltage threshold and the second preset voltage threshold can be set based on the actual application scenario, and the embodiment of the present application does not impose any specific limitation on this.

[0038] The following combination Figure 2 The first AC power source 200 and the second AC power source 400 are shown for illustration.

[0039] like Figure 2As shown, the horizontal axis is time and the vertical axis is voltage. The first AC power supply 200 includes a positive half-cycle and a negative half-axis in each cycle. After the first AC power supply 200 passes through the first signal processing branch 20 and the amplification branch 30, it is converted into a second AC power supply 400. In this embodiment, the amplification branch 30 is specifically configured to add a preset voltage value VT to the first AC power supply 200 (i.e., the entire first AC power supply 200 is translated upward by the preset voltage value VT) to achieve the amplification of the first AC power supply 200 after current limiting and filtering. Subsequently, the voltage of the second AC power supply 400 is greater than zero, so as to facilitate the subsequent processing of the waveform of the entire second AC power supply 400. This is because the controller 40 can usually only process positive voltages. If the first AC power supply 200 is directly input to the controller 40, it will result in the loss of waveforms. Afterwards, when the voltage of the second AC power supply 400 is greater than the first preset voltage threshold VREF1 or less than the second preset voltage threshold VREF2, the controller 40 outputs a control signal to the motor control branch 50 so that the motor control branch 50 controls the motor 300 to run.

[0040] Taking the period from t1 to t4 as an example (the other periods are the same as this period), the time period when the voltage of the second AC power source 400 is greater than the first preset voltage threshold VREF1 corresponds to the time period between t1 and t2. The time period between t1 and t2 is also the time period when the voltage of the first AC power source 200 is greater than the third preset voltage threshold VREF3. The third preset voltage threshold VREF3 is determined by the first preset voltage threshold VREF1 and the amplified value of the amplifying branch 30. For example, in this embodiment, it is assumed that the amplified value of the amplifying branch 30 is the preset voltage value VT. Then the third preset voltage threshold VREF3 is the difference between the first preset voltage threshold VREF1 and the preset voltage value VT.

[0041] Similarly, the time period during which the voltage of the second AC power source 400 is less than the second preset voltage threshold VREF2 corresponds to the time period between t3 and t4. The time period between t3 and t4 is also the time period during which the voltage of the first AC power source 200 is less than the fourth preset voltage threshold VREF4. The fourth preset voltage threshold VREF4 is determined by the second preset voltage threshold VREF2 and the amplified value of the amplifying branch 30. For example, in this embodiment, it is assumed that the amplified value of the amplifying branch 30 is the preset voltage value VT. Then the fourth preset voltage threshold VREF4 is the difference between the second preset voltage threshold VREF2 and the preset voltage value VT.

[0042] Among them, the time period from t1 to t2 and the time period from t3 to t4 are time periods for controlling the operation of the motor 300. It can be seen that only when the voltage of the first AC power source 200 is greater than the third preset voltage threshold VREF3, or the voltage of the first AC power source 200 is less than the fourth preset voltage threshold 400, the controller 40 will output a control signal to control the operation of the motor 300 through the motor control circuit 50. In other words, only when the absolute value of the voltage of the first AC power source 200 is large, the controller 40 will output a control signal to control the operation of the motor 300 through the motor control circuit 50.

[0043] In the related art, since the AC power supply is used to directly power the motor after passing through the electrolytic capacitor, as the AC power supply gradually decreases, the AC power supply cannot meet the power supply demand of the motor. In this case, it is necessary to set the electrolytic capacitor to a capacitor with a larger capacity to play the role of energy storage, thereby maintaining the power supply demand of the motor.

[0044] In the embodiment of the present application, since the controller 40 will output a control signal to control the operation of the motor 300 through the motor control circuit 50 only when the absolute value of the voltage of the first AC power supply 200 is large, the voltage of the first AC power supply 200 can continue to meet the power supply demand of the motor 300, and the first capacitor C1 only needs to play a filtering role without the need to play an energy storage role, so that a first capacitor C1 with a lower capacity can be used to reduce costs.

[0045] In one embodiment, if Figure 3 As shown, the motor driving circuit 100 further includes a second signal processing branch 60 .

[0046] The second signal processing branch 60 is connected between the amplifying branch 30 and the controller 40. The second signal processing branch 60 is configured to limit and filter the second AC power supply and then output it to the controller 40 to protect the controller 40.

[0047] In one embodiment, if Figure 4 As shown, the power supply branch 10 further includes a rectifier unit 11 .

[0048] The first AC power source 200 is rectified by the rectifier unit 11 and filtered by the first capacitor C1 to supply power to the motor 300. The rectifier unit 11 can rectify the first AC power source 200 into a DC power source.

[0049] Please refer to Figure 5 , Figure 5 An example is shown with Figure 4 A circuit structure corresponding to the structure shown. In this embodiment, the first end of the first AC power source 200 is a neutral line and the second end is a live line.

[0050] like Figure 5 As shown, the rectifier unit 11 includes a rectifier bridge U1.

[0051] Among them, the first end of the rectifier bridge U1 is connected to the first end of the first AC power supply 200, the second end of the rectifier bridge U1 is connected to the second end of the first AC power supply 200, the third end of the rectifier bridge U1 is connected to the first end of the first capacitor C1 and the first end of the motor 300, and the fourth end of the rectifier bridge U1, the second end of the first capacitor C1 and the second end of the motor 300 are all grounded GND.

[0052] The rectifier bridge U1 is used to achieve full-wave rectification of the first AC power source 200 .

[0053] In this embodiment, the first signal processing branch 20 includes a first resistor R1 , a second resistor R2 , and a second capacitor C2 .

[0054] Among them, the first resistor R1, the second capacitor C2 and the second resistor R2 are connected in series between the first end and the second end of the first AC power supply 200 in sequence, the connection point of the first resistor R1 and the second capacitor C2 is connected to the first end of the amplification branch 30 (that is, the inverting input end of the first operational amplifier U2), and the connection point of the second capacitor C2 and the second resistor R2 is connected to the second end of the amplification branch 30 (that is, the non-inverting input end of the first operational amplifier U2).

[0055] The first resistor R1 and the second resistor R2 are current limiting resistors. The second capacitor C2 is a filter capacitor.

[0056] In this embodiment, the amplifying branch 30 includes a first operational amplifier U2 , a first diode D1 , a second diode D2 , a third resistor R3 , a fourth resistor R4 , and a fifth resistor R5 .

[0057] Among them, the anode of the first diode D1 and the cathode of the second diode D2 are both connected to the non-inverting input terminal of the first operational amplifier U2, the cathode of the first diode D1 and the anode of the second diode D2 are both connected to the inverting input terminal of the first operational amplifier U2, the third resistor R3 and the fourth resistor R4 are connected in series between the first power supply V1 and the ground GND, the connection point between the third resistor R3 and the fourth resistor R4 is connected to the non-inverting input terminal of the first operational amplifier U2, and the fifth resistor R5 is connected between the inverting input terminal and the output terminal of the first operational amplifier U2.

[0058] The inverting input terminal of the first operational amplifier U2 is the first terminal of the amplifying branch 30 , the non-inverting input terminal of the first operational amplifier U2 is the second terminal of the amplifying branch 30 , and the output terminal of the first operational amplifier U2 is the third terminal of the amplifying branch 30 .

[0059] The first diode D1 and the second diode D2 enable the entire waveform of the first AC power supply 200 after current limiting and filtering to be input to the inverting input terminal of the first operational amplifier U2. The voltage of the first power supply V1 is divided by the third resistor R3 and the fourth resistor R4, and the voltage at the connection point between the third resistor R3 and the fourth resistor R4 is used as the preset voltage value VT in the above embodiment. The combination of the first operational amplifier U2, the first diode D1, the second diode D2, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 can output the entire waveform of the first AC power supply 200 after current limiting and filtering plus the preset voltage value VT, and the output power is the second AC power supply.

[0060] In this embodiment, the second signal processing branch 60 includes a sixth resistor R6 and a third capacitor C3.

[0061] The sixth resistor R6 and the third capacitor C3 are connected in series between the output end of the amplifying branch 30 and the ground GND, and the connection point between the sixth resistor R6 and the third capacitor C3 is connected to the controller 40 .

[0062] The sixth resistor R6 is a current limiting resistor and forms an RC filter with the third capacitor C3.

[0063] The embodiment of the present application further provides a household appliance. The household appliance comprises a motor and a motor driving circuit 100 in any embodiment of the present application. The motor driving circuit 100 is connected to the motor 300.

[0064] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

[0065] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Under the idea of ​​the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. It should be understood by ordinary technicians in this field that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A motor drive circuit, characterized in that: include: a power supply branch connected to the motor and the first AC power source, and configured to supply power to the motor based on the output of the first AC power source, wherein the power supply branch includes a first capacitor connected in parallel with the motor; A first signal processing branch, connected to the first AC power source, configured to perform current limiting and filtering on the first AC power source before outputting; an amplifying branch, connected to the first signal processing branch, and configured to amplify the first AC power after current limiting and filtering and output a second AC power greater than zero; a controller connected to the amplifying branch, and configured to output a control signal in response to the voltage of the second AC power source being greater than a first preset voltage threshold or less than a second preset voltage threshold, wherein the first preset voltage threshold is greater than the second preset voltage threshold; The motor control branch is connected between the controller and the motor, and is configured to control the operation of the motor in response to the control signal.

2. The motor drive circuit according to claim 1, characterized in that: The motor drive circuit also includes a second signal processing branch; The second signal processing branch is connected between the amplifying branch and the controller, and the second signal processing branch is configured to limit and filter the second AC power supply and then output it to the controller.

3. The motor drive circuit according to claim 1 or 2, characterized in that: The power supply branch also includes a rectifier unit; The first AC power source is rectified by the rectifier unit and filtered by the first capacitor to supply power to the motor.

4. The motor drive circuit according to claim 3, characterized in that: The rectifier unit includes a rectifier bridge; The first end of the rectifier bridge is connected to the first end of the first AC power supply, the second end of the rectifier bridge is connected to the second end of the first AC power supply, the third end of the rectifier bridge is connected to the first end of the first capacitor and the first end of the motor, and the fourth end of the rectifier bridge, the second end of the first capacitor and the second end of the motor are all grounded.

5. The motor drive circuit according to claim 1, characterized in that: The first signal processing branch includes a first resistor, a second resistor and a second capacitor; The first resistor, the second capacitor and the second resistor are connected in series between the first end and the second end of the first AC power supply, the connection point between the first resistor and the second capacitor is connected to the first end of the amplifying branch, and the connection point between the second capacitor and the second resistor is connected to the second end of the amplifying branch.

6. The motor drive circuit according to claim 1, characterized in that: The amplifying branch includes a first operational amplifier, a first diode, a second diode, a third resistor, a fourth resistor and a fifth resistor; The anode of the first diode and the cathode of the second diode are both connected to the non-inverting input terminal of the first operational amplifier, the cathode of the first diode and the anode of the second diode are both connected to the inverting input terminal of the first operational amplifier, the third resistor and the fourth resistor are connected in series between the first power supply and the ground, the connection point between the third resistor and the fourth resistor is connected to the non-inverting input terminal of the first operational amplifier, and the fifth resistor is connected between the inverting input terminal and the output terminal of the first operational amplifier; The inverting input terminal of the first operational amplifier is the first terminal of the amplifying branch, the non-inverting input terminal of the first operational amplifier is the second terminal of the amplifying branch, and the output terminal of the first operational amplifier is the third terminal of the amplifying branch.

7. The motor drive circuit according to claim 2, characterized in that: The second signal processing branch includes a sixth resistor and a third capacitor; The sixth resistor and the third capacitor are connected in series between the output end of the amplifying branch and the ground, and the connection point between the sixth resistor and the third capacitor is connected to the controller.

8. A household appliance, characterized in that: It comprises a motor and a motor driving circuit as described in any one of claims 1 to 7, wherein the motor driving circuit is connected to the motor.

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