CN113315446A

CN113315446A - SPIM motor drive circuit and method

Info

Publication number: CN113315446A
Application number: CN202110624027.8A
Authority: CN
Inventors: 刘占军; 马少才
Original assignee: Shanghai Rujing Intelligent Control Technology Co ltd
Current assignee: Shanghai Rujing Intelligent Control Technology Co ltd
Priority date: 2021-06-04
Filing date: 2021-06-04
Publication date: 2021-08-27

Abstract

The invention provides a SPIM motor driving circuit and a method, comprising a driver and an alternating current unit; the driver is connected with a first winding of the SPIM motor and comprises a voltage-multiplying rectifying unit, a direct-current bus and a half-bridge inverter unit; the voltage-multiplying rectification unit is connected with the direct current bus, the direct current bus is connected with the half-bridge inversion unit, the half-bridge inversion unit is connected with one end of the first winding, and the other end of the first winding is connected with input alternating current of the voltage-multiplying rectification unit through a neutral point of the direct current bus; the alternating current unit is connected with a second winding of the SPIM motor. The SPIM motor driving circuit and the method can realize smaller starting current and smaller energy loss, and only need to provide partial energy required by the SPIM motor.

Description

SPIM motor drive circuit and method

Technical Field

The present invention relates to a Single Phase Induction Motor (SPIM), and more particularly, to a SPIM Motor driving circuit and method.

Background

SPIM motors refer to asynchronous motors that use a single phase AC power supply. The SPIM motor has the advantages of convenient use, wide application, simple structure, low cost, low noise, small interference to a radio system and the like because only single-phase alternating current is needed, so the SPIM motor is commonly used in household appliances with low power and small power machines, such as electric fans, washing machines, refrigerators, air conditioners, range hoods, electric drills, medical instruments, small fans, household water pumps and the like.

In the prior art, a SPIM motor is generally composed of a stator, a rotor, a bearing, a casing, an end cover and the like. Because the output power is not large, the rotor of the SPIM motor usually adopts a squirrel-cage rotor, and the stator is provided with a set of working windings called as Main windings (M windings for short), which can only generate positive and negative alternating pulsating magnetic fields in the air gap of the motor, but can not generate a rotating magnetic field, so that the starting torque can not be generated. In order to generate a rotating magnetic field in the air gap of the motor, an auxiliary winding (Aux, abbreviated as a winding) is also required on the stator. Because the magnetic field generated by the auxiliary winding and the magnetic field of the main winding are combined in the air gap of the motor to generate a rotating magnetic field, the motor generates starting torque, so that the rotor can rotate by itself.

The prior art SPIM motor starts in the manner shown in FIG. 1. However, in this way, the starting current of the main winding is too large, which is 5-10 times of the rated current, so that the SPIM motor generates heat seriously, and energy waste is caused.

The SPIM motor starts to enter the running state after being started, and at this time, the capacitor can be connected in the way shown in FIG. 1, or in the way of partial connection shown in FIG. 2, or in the way of only main winding connection shown in FIG. 3. However, in the above mode of operation of the SPIM motor, since the design of the SPIM motor cannot guarantee that the start and operation meet the optimal operating point at the same time, and the flux linkage of the motor is generally elliptical, the torque and rotation speed fluctuation can be caused, and the energy consumption is large; meanwhile, the SPIM motor cannot be adjusted and controlled to be at the optimal working point according to the load condition, and the energy consumption is also high.

When the SPIM motor adopts power electronic devices, the SPIM motor can adopt various operation modes as shown in FIGS. 4-6, and has the advantages of small starting current, stable flux linkage control, small fluctuation of rotating speed and torque, small energy loss, stable rotating speed control and the like. However, all of the energy of the SPIM motor comes from the drive, resulting in the drive needing to withstand the full motor power.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a driving circuit and method for a SPIM motor, which can realize smaller starting current and smaller energy loss, and only needs to provide part of the energy required by the SPIM motor.

To achieve the above and other related objects, the present invention provides a SPIM motor driving circuit, including a driver and an ac unit; the driver is connected with a first winding of the SPIM motor and comprises a voltage-multiplying rectifying unit, a direct-current bus and a half-bridge inverter unit; the voltage-multiplying rectifying unit is connected with the direct current bus, the direct current bus is connected with the half-bridge inversion unit, the half-bridge inversion unit is connected with one end of the first winding, the other end of the first winding is connected with the input alternating current of the voltage-multiplying rectifying unit through a neutral point of the direct current bus, and the alternating current unit is connected with the second winding of the SPIM motor.

In an embodiment of the invention, the half-bridge inverter unit is a three-level inverter or a multi-level inverter.

In an embodiment of the present invention, the dc bus employs two electrolytic capacitors or batteries connected in series.

In an embodiment of the invention, the voltage-doubling rectifying unit employs a voltage-doubling circuit, a half-bridge voltage-doubling BOOST circuit, or a voltage-doubling BOOST PFC circuit.

In an embodiment of the present invention, the ac unit includes an ac power source and a capacitor; and the alternating current power supply and the capacitor are connected in series and then connected to two ends of the second winding.

The invention provides a SPIM motor driving method, which is applied to the SPIM motor driving circuit and comprises the following steps;

converting input alternating current into direct current based on a voltage-multiplying rectifying unit, and inputting the direct current into a direct current bus;

inputting the direct current into a half-bridge inverter unit based on the direct current bus;

converting the direct current into alternating current based on the half-bridge inversion unit, and inputting the alternating current into a first winding of a SPIM motor to drive the first winding;

driving a second winding of the SPIM motor based on an AC unit connected to the second winding.

In an embodiment of the invention, the half-bridge inverter unit is a two-level half-bridge inverter, a three-level half-bridge inverter, or a multi-level half-bridge inverter.

As described above, the SPIM motor driving circuit and method of the present invention have the following advantages:

(1) the second winding is connected to the power grid through the capacitor, so that the starting current is small; the first winding is connected to the driving circuit, so that the starting current is controllable, and the starting current is small;

(2) the current of the first winding can be adjusted to enable the synthetic magnetic field of the first winding and the second winding to be circular, so that the loss of the motor is reduced, and the efficiency of the motor is improved; the torque and rotating speed fluctuation is smaller, so that the motor abrasion is reduced, and the service life of the motor is prolonged;

(3) the driver only needs to provide part of energy required by the motor, and the other part of energy is directly provided by the power grid;

(4) the use of devices is reduced, and the circuit cost is reduced.

Drawings

FIG. 1 is a schematic diagram of a SPIM motor start circuit in an embodiment of the prior art;

FIG. 2 is a schematic structural diagram of a SPIM motor operating circuit in a first embodiment in the prior art;

FIG. 3 is a schematic diagram of a SPIM motor operating circuit in a second embodiment of the prior art;

FIG. 4 is a schematic structural diagram of a SPIM motor control circuit in a third embodiment in the prior art;

FIG. 5 is a schematic diagram of a prior art SPIM motor control circuit in a fourth embodiment;

FIG. 6 is a schematic diagram of a prior art SPIM motor control circuit in a fifth embodiment;

FIG. 7 is a schematic structural diagram of a SPIM motor driving circuit according to an embodiment of the present invention;

FIG. 8 is a flowchart illustrating a SPIM motor driving method according to an embodiment of the present invention.

Description of the element reference numerals

1 driver

11-time voltage rectifying unit

12 DC bus

13 half-bridge inverter unit

2 alternating current unit

21 AC power supply

22 capacitance

3 SPIM motor

31 first winding

32 second winding

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for matching with the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions under which the present invention can be implemented, so that the present invention has no technical significance, and any structural modification, ratio relationship change, or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.

According to the SPIM motor driving circuit and method, the first winding of the SPIM motor is connected to the driver, and the second winding of the SPIM motor is connected to the power grid, so that the driver and the power grid cooperate to supply energy required by the SPIM motor, and meanwhile, smaller starting current and smaller energy loss are realized, and the SPIM motor driving circuit and method have high practicability. Wherein the first winding and the second winding form a main winding and an auxiliary winding of the SPIM motor. Namely, the first winding is a main winding or an auxiliary winding, and the second winding is an auxiliary winding or a main winding.

As shown in fig. 7, in one embodiment, the SPIM motor driving circuit of the present invention includes a driver 1 and an ac unit 2. The driver 1 is used for driving a first winding of the SPIM motor, and the alternating current unit 2 is used for driving a second winding of the SPIM motor, so that a small starting current is realized, and the starting current is controllable.

The driver 1 is connected with a first winding 31 of the SPIM motor 3, and comprises a voltage-multiplying rectifying unit 11, a direct current bus 12 and a half-bridge inverter unit 13.

The voltage-multiplying rectifying unit 11 is connected to the dc bus 12, and is configured to convert an input ac power into a dc power and input the dc power into the dc bus 12. Specifically, the voltage-multiplying rectifying unit 11 adopts a conventional voltage-multiplying circuit, a half-bridge voltage-multiplying BOOST circuit, or a voltage-multiplying BOOST Power Factor Correction (PFC) circuit as the voltage-multiplying rectifying unit 11. In this embodiment, the input end of the voltage-doubling rectifying unit 11 is connected to an inductor, the inductor is connected to the input alternating current AC, and two output ends of the voltage-doubling rectifying unit 11 are respectively connected to two ends of the direct current bus 12.

The dc bus 12 is connected to the half-bridge inverter unit 13, and is configured to input the dc power to the half-bridge inverter unit 13. Specifically, two ends of the dc bus 12 are respectively connected to two input ends of the half-bridge inverter unit 13, and are configured to bear the dc power generated by the voltage-doubling rectifying unit 11, and input the dc power to the half-bridge inverter unit 13. In an embodiment of the present invention, the dc bus 12 employs two electrolytic capacitors or batteries connected in series.

The half-bridge inverter unit 13 is connected to one end of the first winding 31, and the other end of the first winding 31 is connected to the input AC through a neutral point of the dc bus 12. The output end of the half-bridge inverter unit 13 is connected to one end of the first winding 31, and is configured to convert the dc power into an ac power, and input the ac power into the first winding 31 of the SPIM motor 3 to drive the first winding 31. Specifically, the half-bridge inverter unit 13 can convert dc power into ac power, and the converted ac power is input to the first winding 31 to complete driving of the first winding 31. In an embodiment of the present invention, the half-bridge inverter unit 13 employs a two-level half-bridge inverter, a three-level half-bridge inverter, or a multi-level half-bridge inverter.

The ac unit 2 is connected to the second winding 32 of the SPIM motor 3, and the second winding 32 is driven by inputting ac power. In an embodiment of the present invention, the ac unit 2 includes an ac power source 21 and a capacitor 22. The alternating current power supply 21 and the capacitor 22 are connected in series and then connected to two ends of the second winding 32 to complete the driving of the second winding 32.

As shown in fig. 8, in an embodiment, the driving method of the SPIM motor driving circuit of the present invention includes the following steps;

step S1, the voltage-doubler-based rectification unit converts the input ac power into dc power, and inputs the dc power into the dc bus.

Specifically, the voltage-multiplying rectifying unit 11 is a conventional voltage-multiplying circuit, a half-bridge voltage-multiplying BOOST circuit, or a voltage-multiplying BOOST PFC circuit. In this embodiment, a neutral point of the voltage-doubling rectifying unit is connected to an inductor, the inductor is connected to the input ac power, and two ends of the voltage-doubling rectifying unit are respectively connected to two ends of the dc bus.

And step S2, inputting the direct current into a half-bridge inversion unit based on the direct current bus.

Specifically, two ends of the dc bus are respectively connected to two input ends of the half-bridge inverter unit, and are configured to carry the dc power generated by the voltage-doubling rectifying unit and input the dc power to the half-bridge inverter unit. In an embodiment of the present invention, the dc bus employs two electrolytic capacitors or batteries connected in series.

Step S3, converting the dc power into ac power based on the half-bridge inverter unit, and inputting the ac power to a first winding of a SPIM motor to drive the first winding; driving a second winding of the SPIM motor based on an AC unit connected to the second winding.

Specifically, the half-bridge inverter unit can convert direct current into alternating current, and the converted alternating current is input to the first winding to complete driving of the first winding.

Specifically, the alternating current unit comprises an alternating current power supply and a capacitor. And the alternating current power supply and the capacitor are connected in series and then connected to two ends of the second winding to complete the driving of the second winding.

Preferably, the driving method of the SPIM motor according to the present invention further includes adjusting the current of the first winding to make the resultant magnetic field of the first winding and the second winding form a circular shape, so as to reduce the damage and wear of the SPIM motor and improve the energy efficiency and the life of the SPIM motor.

In summary, the SPIM motor driving circuit and method of the invention have the advantages that the second winding is connected to the power grid through the capacitor, so the starting current is small; the first winding is connected to the driving circuit, so that the starting current is controllable; the current of the first winding can be adjusted to enable the synthetic magnetic field of the first winding and the second winding to be circular, so that the loss of the motor is reduced, and the efficiency of the motor is improved; the torque and rotating speed fluctuation is smaller, so that the motor abrasion is reduced, and the service life of the motor is prolonged; the driver only needs to provide part of energy required by the motor, and the other part of energy is directly provided by the power grid; the use of devices is reduced, and the circuit cost is reduced. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A SPIM motor drive circuit characterized by: comprises a driver and an alternating current unit;

the driver is connected with a first winding of the SPIM motor and comprises a voltage-multiplying rectifying unit, a direct-current bus and a half-bridge inverter unit; the voltage-multiplying rectification unit is connected with the direct current bus, the direct current bus is connected with the half-bridge inversion unit, the half-bridge inversion unit is connected with one end of the first winding, and the other end of the first winding is connected with input alternating current of the voltage-multiplying rectification unit through a neutral point of the direct current bus;

the alternating current unit is connected with a second winding of the SPIM motor.

2. The SPIM motor drive circuit of claim 1, wherein: the half-bridge inversion unit adopts a two-level inverter or a three-level half-bridge inverter or a multi-level half-bridge inverter.

3. The SPIM motor drive circuit of claim 1, wherein: the direct current bus adopts two electrolytic capacitors or batteries connected in series.

4. The SPIM motor drive circuit of claim 1, wherein: the voltage-multiplying rectifying unit adopts a voltage-multiplying circuit, a half-bridge voltage-multiplying BOOST circuit or a voltage-multiplying type BOOST PFC circuit.

5. The SPIM motor drive circuit of claim 1, wherein: the alternating current unit comprises an alternating current power supply and a capacitor; and the alternating current power supply and the capacitor are connected in series and then connected to two ends of the second winding.

6. A SPIM motor driving method applied to the SPIM motor driving circuit of one of claims 1 to 5, characterized in that: comprises the following steps;

converting the direct current into alternating current based on the half-bridge inversion unit, and inputting the alternating current into a first winding of a SPIM motor to drive the first winding; driving a second winding of the SPIM motor based on an AC unit connected to the second winding.

7. The SPIM motor drive method of claim 6, wherein: the half-bridge inversion unit adopts a two-level half-bridge inverter or a three-level half-bridge inverter or a multi-level half-bridge inverter.

8. The SPIM motor drive method of claim 6, wherein: the direct current bus adopts two electrolytic capacitors or batteries connected in series.

9. The SPIM motor drive method of claim 6, wherein: the voltage-multiplying rectifying unit adopts a voltage-multiplying circuit, a half-bridge voltage-multiplying BOOST circuit or a voltage-multiplying type BOOST PFC circuit.

10. The SPIM motor drive method of claim 6, wherein: the alternating current unit comprises an alternating current power supply and a capacitor; and the alternating current power supply and the capacitor are connected in series and then connected to two ends of the second winding.