Motor and control method thereof

Abstract

The present invention provides a motor and a control method thereof, wherein the motor includes: a rectifier circuit, a power decoupling circuit and an inverter circuit; wherein the rectifier circuit, the power decoupling circuit and the inverter circuit are connected in parallel to the motor; the rectifier circuit is connected to the input end of the motor, and the inverter circuit is connected to the output end of the motor; the rectifier circuit is used to convert the alternating current input to the motor into direct current, and input the direct current into the power decoupling circuit; the power decoupling circuit is used to store electric energy according to the direct current, and provide electric energy to the motor; the inverter circuit is used to convert the direct current into alternating current and output it through the output end. Through the present invention, the problem of the related art that the electrolytic capacitor is connected in parallel on the DC side as an energy storage and buffer unit, resulting in a short service life and low reliability of the entire control system is solved.

Description

Technical Field

[0001] The present invention relates to the field of electromechanics, and in particular to a motor and a control method thereof. Background Art

[0002] Permanent magnet synchronous motors are widely used in the field of industrial control, and driving them with high reliability and high efficiency has become the focus of relevant scholars. In traditional motor control systems, electrolytic capacitors are usually connected in parallel on the DC side as energy storage and buffer units, but due to the defects of electrolytic capacitors themselves, the service life and reliability of the entire control system are affected. Figure 1 This is a schematic diagram of a traditional single-phase system motor control circuit, such as Figure 1 As shown in the figure, C is an electrolytic capacitor, the left side of capacitor C is a rectifier circuit, the right side is an inverter circuit, and power flows from left to right. This circuit generally requires a parallel electrolytic capacitor C on the DC side for filtering to stabilize the output voltage. However, electrolytic capacitors are large in size, high in cost, low in power density, and high in loss, which will reduce the reliability of the motor control system and shorten its service life.

[0003] There is currently no effective solution to the above-mentioned problems in the related art. Summary of the invention

[0004] The embodiment of the present invention provides a motor and a control method thereof, so as to at least solve the problem in the related art that an electrolytic capacitor is connected in parallel on the DC side as an energy storage and buffer unit, resulting in a short service life and low reliability of the entire control system.

[0005] According to one embodiment of the present invention, a motor is provided, comprising: a rectifier circuit, a power decoupling circuit and an inverter circuit; wherein the rectifier circuit, the power decoupling circuit and the inverter circuit are connected in parallel to the motor; the rectifier circuit is connected to the input end of the motor, and the inverter circuit is connected to the output end of the motor; the rectifier circuit is used to convert the alternating current input to the motor into direct current, and input the direct current into the power decoupling circuit; the power decoupling circuit is used to store electrical energy according to the direct current, and provide electrical energy to the motor; the inverter circuit is used to convert the direct current into alternating current and output it through the output end.

[0006] Furthermore, when the motor is powered on normally, the power decoupling circuit stores electrical energy while providing electrical energy to the motor; when the input voltage cannot meet the requirements of the motor, the power decoupling circuit provides electrical energy to the motor through the stored electrical energy.

[0007] Further, the power decoupling circuit includes: a first power switch tube, a second power switch tube, a first inductor, a second inductor, a first thin film capacitor and a second thin film capacitor; wherein, the collector of the first power switch tube is connected to one end of the first inductor, the other end of the first inductor is connected to one end of the first thin film capacitor connected in series, the other end of the first thin film capacitor is connected to one end of the second thin film capacitor, the other end of the second thin film capacitor is connected to the emitter of the second power switch tube, the collector of the second power switch tube is connected to one end of the second inductor, and the other end of the second inductor is connected to the emitter of the first power switch tube; the connection point between the collector of the second power switch tube and the second inductor is connected to the connection point between the first thin film capacitor and the second thin film capacitor.

[0008] Furthermore, the power decoupling capacitor also includes: a first diode, a second diode and a third diode; wherein the first diode is connected in series between the first inductor and the first film capacitor; one end of the second diode is connected to the emitter of the first power switch tube, and the other end of the second diode is connected to the collector of the second power switch tube.

[0009] According to another embodiment of the present invention, a method for controlling a motor is provided, wherein the motor includes: a rectifier circuit, a power decoupling circuit and an inverter circuit; the method includes: the rectifier circuit converts the alternating current input to the motor into direct current, and inputs the direct current into the power decoupling circuit; the power decoupling circuit stores electrical energy based on the direct current, and provides electrical energy to the motor; the inverter circuit converts the direct current into alternating current and outputs it through an output terminal.

[0010] Furthermore, when the motor is powered on normally, the power decoupling circuit stores electrical energy while providing electrical energy to the motor; when the input voltage cannot meet the requirements of the motor, the power decoupling circuit provides electrical energy to the motor through the stored electrical energy.

[0011] Further, the power decoupling circuit includes: a first power switch tube, a second power switch tube, a first inductor, a second inductor, a first thin film capacitor and a second thin film capacitor; wherein, the collector of the first power switch tube is connected to one end of the first inductor, the other end of the first inductor is connected to one end of the first thin film capacitor connected in series, the other end of the first thin film capacitor is connected to one end of the second thin film capacitor, the other end of the second thin film capacitor is connected to the emitter of the second power switch tube, the collector of the second power switch tube is connected to one end of the second inductor, and the other end of the second inductor is connected to the emitter of the first power switch tube; the connection point between the collector of the second power switch tube and the second inductor is connected to the connection point between the first thin film capacitor and the second thin film capacitor.

[0012] Furthermore, the power decoupling capacitor also includes: a first diode, a second diode and a third diode; wherein the first diode is connected in series between the first inductor and the first film capacitor; one end of the second diode is connected to the emitter of the first power switch tube, and the other end of the second diode is connected to the collector of the second power switch tube.

[0013] Furthermore, when the motor is powered on normally, the first power switch tube and the second power switch tube are both turned on, the second inductor is charged through the rectifier circuit, and power is supplied to the motor through the first film capacitor and the second film capacitor.

[0014] Furthermore, when the input voltage cannot meet the demand of the motor, the first power switch tube and the second power switch tube are both turned off, and the second inductor releases the stored electrical energy.

[0015] Through the present invention, a power decoupling circuit is provided in the motor so that ripple and pulse power are released through the decoupling circuit, thereby improving the power quality of the output voltage and improving the stability and reliability of the motor, thereby solving the problem in the related art of using electrolytic capacitors in parallel on the DC side as energy storage and buffering units, resulting in a short service life and low reliability of the entire control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 It is a schematic diagram of the motor control circuit of the traditional single-phase system;

[0018] Figure 2 is a circuit diagram of a motor according to this embodiment;

[0019] Figure 3 is an optional circuit diagram of a motor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0022] Example 1

[0023] Figure 2 is a circuit diagram of a motor according to this embodiment, such as Figure 2 As shown, the motor includes: a rectifier circuit, a power decoupling circuit and an inverter circuit; wherein the rectifier circuit, the power decoupling circuit and the inverter circuit are connected in parallel to the motor; the rectifier circuit is connected to the input end of the motor, and the inverter circuit is connected to the output end of the motor;

[0024] Among them, the rectifier circuit is used to convert the AC power input into the motor into DC power, and input the DC power into the power decoupling circuit; the power decoupling circuit is used to store electric energy according to the DC power and provide electric energy to the motor; the inverter circuit is used to convert the DC power into AC power and output it through the output end.

[0025] Furthermore, in an optional implementation of the present embodiment, when the motor is powered on normally, the power decoupling circuit stores electrical energy while providing electrical energy to the motor; when the input voltage cannot meet the requirements of the motor, the power decoupling circuit provides electrical energy to the motor through the stored electrical energy.

[0026] It can be seen that Figure 2 As shown in the figure, power flows from left to right, passing through the power decoupling circuit in the middle. Part of the grid energy is stored in the decoupling circuit, and the other part directly supplies power to the permanent magnet synchronous motor. When the grid voltage is low, this part of the released energy provides power to the permanent magnet synchronous motor, reducing the required storage energy of the capacitor, that is, reducing the capacitance of the capacitor.

[0027] Furthermore, the power decoupling circuit of this embodiment may further include: a first power switch tube S1, a second power switch tube S2, a first inductor L1, a second inductor L2, a first film capacitor C1 and a second film capacitor C2; wherein,

[0028] The collector of the first power switch tube S1 is connected to one end of the first inductor L1, the other end of the first inductor L1 is connected to one end of the first film capacitor C1 connected in series, the other end of the first film capacitor C1 is connected to one end of the second film capacitor C2, the other end of the second film capacitor C2 is connected to the emitter of the second power switch tube S2, the collector of the second power switch tube S2 is connected to one end of the second inductor L2, and the other end of the second inductor L2 is connected to the emitter of the first power switch tube S1; the connection point between the collector of the second power switch tube S1 and the second inductor L2 is connected to the connection point between the first film capacitor C1 and the second film capacitor C2.

[0029] Furthermore, the power decoupling capacitor in this embodiment further includes: a first diode D1, a second diode D2 and a third diode D3; wherein,

[0030] The first diode D1 is connected in series between the first inductor L and the first film capacitor C1; one end of the second diode D2 is connected to the emitter of the first power switch tube S1, and the other end of the second diode D2 is connected to the collector of the second power switch tube S2.

[0031] Based on the above power decoupling circuit, in a specific implementation of this embodiment, the motor in this embodiment can be a permanent magnet synchronous motor without electrolytic capacitors, and the circuit of the motor is as follows: Figure 3 shown.

[0032] When the power switch tubes S1 and S2 are both turned on, the electric energy of the rectifier link charges L2, and the voltage across the inductor is the grid input voltage, and the inductor current rises. At this time, the motor is powered by the film capacitor, and the voltage across the film capacitor decreases. When the power switch tubes S1 and S2 are both turned off, L2 begins to release the stored electric energy. At this time, there are two circuits to provide electric energy to the motor. One is that the grid energy directly provides the film capacitor and motor energy through the inductor L1 and D1; the other is that the inductor L2 continues to flow through D2D3 to provide energy for the motor and the film capacitor C2, and the inductor current decreases. At this time, the film capacitor is in a charging state, and the voltage across the two ends increases.

[0033] By controlling the on and off of the switch tubes S1 and S2, the power circuit is decoupled. The power circuit absorbs all ripple voltages through the charge and discharge of L2, thereby improving the power quality on the DC bus side.

[0034] That is to say, this embodiment further provides a method for controlling a motor, wherein the motor includes: a rectifier circuit, a power decoupling circuit and an inverter circuit; the method includes:

[0035] Step S102, the rectifier circuit converts the AC power input to the motor into DC power, and inputs the DC power to the power decoupling circuit;

[0036] Step S104, the power decoupling circuit stores electric energy according to the direct current and provides electric energy to the motor;

[0037] Step S106: the inverter circuit converts the DC power into AC power and outputs the AC power through the output terminal.

[0038] Among them, the above step S104 can be further implemented as follows: when the motor is powered on normally, the power decoupling circuit stores electrical energy while providing electrical energy to the motor; when the input voltage cannot meet the motor requirements, the power decoupling circuit provides electrical energy to the motor through the stored electrical energy.

[0039] It should be noted that the power decoupling circuit of this embodiment may further include: a first power switch tube S1, a second power switch tube S2, a first inductor L1, a second inductor L2, a first film capacitor C1 and a second film capacitor C2; wherein,

[0040] The collector of the first power switch tube S1 is connected to one end of the first inductor L1, the other end of the first inductor L1 is connected to one end of the first film capacitor C1 connected in series, the other end of the first film capacitor C1 is connected to one end of the second film capacitor C2, the other end of the second film capacitor C2 is connected to the emitter of the second power switch tube S2, the collector of the second power switch tube S2 is connected to one end of the second inductor L2, and the other end of the second inductor L2 is connected to the emitter of the first power switch tube S1; the connection point between the collector of the second power switch tube S1 and the second inductor L2 is connected to the connection point between the first film capacitor C1 and the second film capacitor C2.

[0041] Furthermore, the power decoupling capacitor in this embodiment also includes: a first diode D1, a second diode D2 and a third diode D3; wherein the first diode D1 is connected in series between the first inductor L and the first film capacitor C1; one end of the second diode D2 is connected to the emitter of the first power switch tube S1, and the other end of the second diode D2 is connected to the collector of the second power switch tube S2.

[0042] Based on this, when the motor is powered on normally, the first power switch tube S1 and the second power switch tube S2 are both turned on, the second inductor L2 is charged through the rectifier circuit, and the motor is powered through the first film capacitor C1 and the second film capacitor C2. When the input voltage cannot meet the motor requirements, the first power switch tube S1 and the second power switch tube S2 are both turned off, and the second inductor L2 releases the stored electrical energy.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A motor, characterized in that: include: A rectifier circuit, a power decoupling circuit and an inverter circuit; wherein the rectifier circuit, the power decoupling circuit and the inverter circuit are sequentially connected in series to the motor; the rectifier circuit is connected to the power input terminal, and the output terminal of the inverter circuit is connected to the motor; The rectifier circuit is used to convert the alternating current input to the motor into direct current, and input the direct current into the power decoupling circuit; The power decoupling circuit is used to store electric energy according to the direct current and to provide electric energy to the motor; The inverter circuit is used to convert the direct current into alternating current and output it through the output terminal; The power decoupling circuit includes: a first power switch tube, a second power switch tube, a first inductor, a second inductor, a first film capacitor and a second film capacitor; wherein the collector of the first power switch tube is connected to one end of the first inductor, the other end of the first inductor is connected to one end of the first film capacitor connected in series, the other end of the first film capacitor is connected to one end of the second film capacitor, the other end of the second film capacitor is connected to the emitter of the second power switch tube, the collector of the second power switch tube is connected to one end of the second inductor, and the other end of the second inductor is connected to the emitter of the first power switch tube; the connection point between the collector of the second power switch tube and the second inductor is connected to the connection point between the first film capacitor and the second film capacitor; The power decoupling circuit also includes: a first diode, a second diode and a third diode; wherein the first diode is connected in series between the first inductor and the first thin film capacitor, the anode of the first diode is connected to the first inductor, and the cathode of the first diode is connected to the first thin film capacitor; the cathode of the second diode is connected to the emitter of the first power switch tube, and the anode of the second diode is connected to the emitter of the second power switch tube; the third diode is connected in series between the second inductor and the second thin film capacitor, the anode of the third diode is connected to the second inductor, and the cathode of the third diode is connected to the second thin film capacitor.

2. The motor according to claim 1, characterized in that When the motor is powered on normally, the power decoupling circuit stores electric energy while providing electric energy to the motor; When the input voltage cannot meet the demand of the motor, the power decoupling circuit provides electrical energy to the motor through the stored electrical energy.

3. A method for controlling a motor, characterized in that: The motor comprises: a rectifier circuit, a power decoupling circuit and an inverter circuit, wherein the rectifier circuit, the power decoupling circuit and the inverter circuit are sequentially connected in series to the motor; the method comprises: The rectifier circuit converts the AC power input to the motor into DC power, and inputs the DC power to the power decoupling circuit; The power decoupling circuit stores electric energy according to the direct current and provides electric energy to the motor; The inverter circuit converts the DC power into AC power and outputs it through the output terminal; The power decoupling circuit includes: a first power switch tube, a second power switch tube, a first inductor, a second inductor, a first film capacitor and a second film capacitor; wherein the collector of the first power switch tube is connected to one end of the first inductor, the other end of the first inductor is connected to one end of the first film capacitor connected in series, the other end of the first film capacitor is connected to one end of the second film capacitor, the other end of the second film capacitor is connected to the emitter of the second power switch tube, the collector of the second power switch tube is connected to one end of the second inductor, and the other end of the second inductor is connected to the emitter of the first power switch tube; the connection point between the collector of the second power switch tube and the second inductor is connected to the connection point between the first film capacitor and the second film capacitor; The power decoupling circuit also includes: a first diode, a second diode and a third diode; wherein the first diode is connected in series between the first inductor and the first thin film capacitor, the anode of the first diode is connected to the first inductor, and the cathode of the first diode is connected to the first thin film capacitor; the cathode of the second diode is connected to the emitter of the first power switch tube, and the anode of the second diode is connected to the emitter of the second power switch tube; the third diode is connected in series between the second inductor and the second thin film capacitor, the anode of the third diode is connected to the second inductor, and the cathode of the third diode is connected to the second thin film capacitor.

4. The method according to claim 3, characterized in that: When the motor is powered on normally, the power decoupling circuit stores electric energy while providing electric energy to the motor; When the input voltage cannot meet the demand of the motor, the power decoupling circuit provides electrical energy to the motor through the stored electrical energy.

5. The method according to claim 3, characterized in that: When the motor is powered on normally, the first power switch tube and the second power switch tube are both turned on, the second inductor is charged through the rectifier circuit, and power is supplied to the motor through the first film capacitor and the second film capacitor.

6. The method according to claim 3, characterized in that When the input voltage cannot meet the demand of the motor, the first power switch tube and the second power switch tube are both turned off, and the second inductor releases the stored electrical energy.

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