CN215120633U

CN215120633U - SPIM motor drive circuit

Info

Publication number: CN215120633U
Application number: CN202121243396.4U
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: 2021-12-10
Anticipated expiration: 2031-06-04

Abstract

The utility model provides a SPIM motor driving circuit, which comprises a driver and an alternating current unit; the driver comprises a rectifying unit, a direct current bus, a first inversion unit and a second inversion unit, wherein the rectifying unit is connected with the direct current bus, the direct current bus is respectively connected with the first inversion unit and the second inversion unit, and the first inversion unit is connected with a first winding of the SPIM motor through a first switch; the second inverter unit is connected with a second winding of the SPIM motor; the alternating current unit comprises an input alternating current, a second switch and a capacitor; the input alternating current is connected with the first winding through the second switch and the capacitor and is connected with the input end of the rectifying unit. The utility model discloses a SPIM motor drive circuit can realize less start current and less energy loss, can realize the frequency conversion and the power frequency drive of SPIM motor, and only need provide the required partial energy of SPIM motor under the power frequency operating condition.

Description

SPIM motor drive circuit

Technical Field

The utility model relates to a Single Phase asynchronous machine (SPIM), especially relate to a SPIM Motor drive circuit.

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.

SUMMERY OF THE UTILITY MODEL

In view of the above disadvantages of the prior art, the present invention provides a driving circuit for a SPIM motor, which can realize a smaller starting current and a smaller energy loss, and can realize a variable frequency operation of the SPIM motor; under the power frequency operation mode of the power grid, only partial energy required by the SPIM motor needs to be provided, and the hot switching of drive control and power grid control can be realized.

To achieve the above and other related objects, the present invention provides a SPIM motor driving circuit, which includes a driver and an ac unit; the driver comprises a rectifying unit, a direct current bus, a first inversion unit and a second inversion unit, wherein the rectifying unit is connected with the direct current bus, the direct current bus is respectively connected with the first inversion unit and the second inversion unit, and the first inversion unit is connected with a first winding of the SPIM motor through a first switch; the second inverter unit is connected with a second winding of the SPIM motor; the alternating current unit comprises an input alternating current, a second switch and a capacitor; the input alternating current is connected with the first winding through the second switch and the capacitor and is connected with the input end of the rectifying unit.

In an embodiment of the present invention, the first inverter unit and the second inverter unit employ a two-level inverter, a three-level inverter, or a multi-level inverter.

In an embodiment of the present invention, the rectifying unit adopts a single-phase uncontrolled rectifying circuit, a single-phase PWM rectifier, a single-phase BOOST rectifying circuit, a totem-pole structure rectifying circuit or a voltage-doubling rectifying circuit.

As described above, the SPIM motor driving circuit of the present invention has the following advantages:

(1) the motor can be driven to start by adopting an inversion unit, soft start is realized by adopting vector control, and the starting current is small; the first winding and the second winding of the motor are in current fit to form a circular magnetic field in the motor, so that the loss of the motor is reduced, and the efficiency of the motor is improved; the torque and the rotating speed fluctuation are small, so that the motor abrasion is reduced, and the service life of the motor is prolonged;

(2) in the inverter unit mode, the motor can realize variable frequency operation;

(3) when the rotating speed of the motor magnetic field reaches the frequency of the power grid, S1 can be disconnected, S2 can be closed, and the hot switch from variable frequency driving to power frequency driving is realized, so that the driver and the power grid jointly control the motor to operate; the circular magnetic field is formed by adjusting the current of the second winding to match the current of the first winding, so that the fluctuation of the rotating speed of the motor is small, and the loss is small; in the mode, the power grid bears partial energy required by the motor, and the frequency converter bears partial energy required by the motor;

(4) if the inverter switching tube connected with the first winding is damaged, the switch S1 can be disconnected, the switch S2 can be closed, the current of the first winding is controlled to be matched with the current of the second winding to form a circular magnetic field, the starting of the motor is realized, and the current is small and controlled in the whole process; and the inverter only bears part of the energy required by the motor to operate.

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 an embodiment of the SPIM motor driving circuit 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 rectifying unit

12 DC bus

13 first inverter unit

14 second inverter unit

15 first switch

2 alternating current unit

21 input AC

22 second switch

23 capacitance

3 SPIM motor

31 first winding

32 second winding

Detailed Description

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

It should be understood that the structure, ratio, size and the like shown in the drawings attached to the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by those skilled in the art, and are not used for limiting the limit conditions that the present invention can be implemented, so that the present invention has no technical essential meaning, and any structure modification, ratio relationship change or size adjustment should still fall within the scope that the technical content disclosed in the present invention can cover without affecting the function that the present invention can produce and the purpose that the present invention can achieve. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description, and are not intended to limit the scope of the present invention, and changes or adjustments of the relative relationship thereof may be made without substantial technical changes, and the present invention is also regarded as the scope of the present invention.

The utility model discloses a SPIM motor drive circuit connects respectively in the contravariant unit through the second winding with the SPIM motor and first winding, and will first winding is based on switch circuit connects in the electric wire netting to realize that SPIM can be by driver control frequency conversion operation, also can make first winding can optionally realize the SPIM motor and decide the operation frequently based on contravariant unit and electric wire netting collaborative drive, realized the hot switch of drive control and electric wire netting operation control that decides frequently, realized less start current and less energy loss simultaneously, had the practicality. Wherein the first winding and the second winding of the SPIM motor 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 an embodiment, the SPIM motor driving circuit of the present invention includes a driver 1 and an ac unit 2.

The driver 1 includes a rectifying unit 11, a dc bus 12, a first inverting unit 13, a second inverting unit 14, and a first switch 15.

The rectifying unit 11 is connected to the dc bus 12, and is configured to convert an input ac current Vac into a dc current, and input the dc current into the dc bus 12. Specifically, the rectification unit adopts a single-phase uncontrolled rectification circuit, a single-phase PWM rectifier, a single-phase BOOST rectification circuit, a totem-pole structure rectification circuit or a voltage doubling rectification circuit. Preferably, the rectifying unit 11 may adopt a two-level rectifying circuit, a three-level rectifying circuit or a multi-level rectifying circuit. The rectifier circuit that only needs to convert the input alternating current into the direct current is in the protection scope of the utility model. In this embodiment, the input ac Vac and the inductor are connected in series between two input ends of the rectifying unit 11, and two output ends are respectively connected to two ends of the dc bus 12.

The dc bus 12 is connected to the first inverter unit 13 and the second inverter unit 14, respectively, and is configured to input the dc power to the first inverter unit 13 and the second inverter unit 14, respectively. Specifically, two ends of the dc bus 12 are respectively connected to two input ends of the first inverter unit 13 and the second inverter unit 14, and are configured to carry the dc power generated by the rectifier unit 11 and input the dc power to the first inverter unit 13 and the second inverter unit 14. In an embodiment of the present invention, the dc bus 12 is an electrolytic capacitor or a battery.

The first inverter unit 13 is connected to the first winding 31 of the SPIM motor 3 through a first switch 15, and is configured to convert the direct current into an alternating current, and input the alternating current to the first winding 31 through the first switch 15. Specifically, two input ends of the first inverter unit 13 are connected to two output ends of the dc bus 12, and the two output ends are connected to two ends of the first winding 31 respectively after passing through the first switch 15. Therefore, when the first switch 15 is closed, the output ac power of the first inverter unit 13 can drive the first winding 31. In an embodiment of the present invention, the first inverter unit 13 is a two-level inverter, a three-level inverter, or a multi-level inverter.

The second inverter unit 14 is connected to the second winding 32 of the SPIM motor 3, and is configured to convert the direct current into an alternating current, and input the alternating current to the second winding 32. Specifically, two input ends of the second inverter unit 14 are connected to two output ends of the dc bus 12, and the two output ends are respectively connected to two ends of the second winding 32, so as to drive the second winding 32. In an embodiment of the present invention, the second inverter unit 14 is a two-level inverter, a three-level inverter, or a multi-level inverter.

The alternating current unit 2 comprises an input alternating current 21, a second switch 22 and a capacitor 23; the input alternating current 21 is connected to the first winding 31 through a second switch 22, and is used for inputting the input alternating current into the first winding 31 through the second switch 22, and meanwhile, the input alternating current is also input into the input end of the rectifying unit 11. In particular, the input alternating current 21 may be provided by a power grid, which is connected across the first winding 31 via the second switch 22 and the capacitor 23. Therefore, when the second switch 22 is closed, the input ac 21 drives the first winding 31.

In the starting and frequency conversion control process of the SPIM motor driving circuit, the first switch is closed, the second switch is opened, the first winding is driven based on the first inversion unit, the second winding is driven based on the second inversion unit, and the current of the first winding is 90 degrees ahead of the current of the second winding. The control mode of the SPIM motor connected with the driver can realize the variable frequency operation of the motor. When the SPIM motor needs to operate at power frequency, the SPIM motor can operate to the frequency of a power frequency power grid in a variable frequency driving mode, in the process, the phase of the driving voltage Vm of the second winding is kept consistent with the phase of Vac, the first switch S1 is switched off, the second switch S2 is switched on, the first winding 31 is driven based on the alternating current input power Vac, the second winding 32 is driven based on the driver, so that the heat switching from variable frequency to power frequency is realized, and at the moment, the driver only provides partial energy required by the operation of the motor. When the first inversion unit is damaged, the first switch is switched off, the second switch is switched on, the first winding is driven based on the alternating current unit, and the second winding is driven based on the second inversion unit. Therefore, the utility model discloses a SPIM motor drive circuit driver can realize frequency conversion control and power frequency control of deciding frequently simultaneously, can realize frequency conversion drive control and decide the hot switch of controlling frequently to the electric wire netting power frequency, has guaranteed the reliability of circuit operation.

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

and step S1, when the SPIM motor is started or in a frequency conversion control state, closing the first switch and opening the second switch.

Specifically, during the starting and frequency conversion control process of the SPIM motor, the first switch is closed, the second switch is opened, the first winding is driven by the first inverter unit, and the second winding is driven by the second inverter unit.

Step S2, driving a first winding of the SPIM motor based on the first inversion unit; and driving a second winding of the SPIM motor based on a second inverter unit.

Specifically, the alternating current output by the first inversion unit directly drives the first winding. The alternating current output by the second inversion unit directly drives the second winding.

In an embodiment of the present invention, the SPIM motor of the present invention can operate under variable frequency and power frequency; if the SPIM motor needs to operate under a power frequency condition, the motor can be driven by two inverter bridges to operate to the power frequency, then the first switch S1 is switched off, and the second switch S2 is switched on, so that the SPIM motor is switched from non-power frequency to power frequency operation; if the inverter bridge connected with the first winding is damaged, the first switch S1 is disconnected, the second switch S2 is closed, and the SPIM motor can still be started and operated at power frequency by controlling the current of the second winding and matching with the current of the first winding. The reliability of the circuit operation is ensured.

Preferably, the driving method of the SPIM motor of the present invention further includes adjusting the current of the first winding and the current of the second 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.

To sum up, the utility model discloses SPIM motor soft start, frequency conversion control and the control of deciding frequently that SPIM motor drive circuit can realize. The starting current is small; can be through adjusting winding circuit for the synthetic magnetic field of first winding and second winding is circular, and torque, rotational speed are undulant little, and is efficient, reduces motor wear, promotes the motor life-span, and can realize drive control to the hot switch of electric wire netting power frequency fixed frequency control. Even under the condition that the first contravariant unit of driver takes place the switch tube and damages, through the control to first switch and second switch, adjust the second winding current and cooperate first winding current to form circular magnetic field, also can guarantee SPIM motor's undercurrent and start and power frequency operation. Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may 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 comprises a rectifying unit, a direct current bus, a first inversion unit and a second inversion unit, wherein the rectifying unit is connected with the direct current bus, the direct current bus is respectively connected with the first inversion unit and the second inversion unit, and the first inversion unit is connected with a first winding of the SPIM motor through a first switch; the second inverter unit is connected with a second winding of the SPIM motor;

the alternating current unit comprises an input alternating current, a second switch and a capacitor; the input alternating current is connected with the first winding through the second switch and the capacitor and is connected with the input end of the rectifying unit.

2. The SPIM motor drive circuit of claim 1, wherein: the first inversion unit and the second inversion unit adopt a two-level inverter, a three-level inverter or a multi-level inverter.

3. The SPIM motor drive circuit of claim 1, wherein: the rectification unit adopts a single-phase uncontrolled rectification circuit, a single-phase PWM rectifier, a single-phase BOOST rectification circuit, a totem-pole structure rectification circuit or a voltage doubling rectification circuit.