CN221227385U - Motor circuit and vehicle - Google Patents

Abstract

The present application provides a motor circuit and a vehicle. The motor circuit includes a motor and a switching circuit. The motor includes a multi-phase winding, at least two phase windings of the multi-phase winding are connected to form a neutral point, and there are at least two neutral points. The switching circuit is connected between at least two neutral points, and is used to control the on and off of the line between the neutral points; when the motor is in a first speed state, the switching circuit is in a first state, and the switching circuit disconnects the line between the neutral points; when the motor is in a second speed state, the switching circuit is in a second state, and the switching circuit connects the line between the neutral points. The motor circuit provided in the present application controls the state of the motor by adding a switching circuit connected between the neutral points, and can control the number of motor phases and the size of the motor magnetic flux at different speeds to improve the efficiency and torque density of the motor.

Description

Motor circuits and vehicles

Technical Field

The present application relates to the field of motor control technology, and in particular to a motor circuit and a vehicle.

Background technique

At present, the driving motors of electric vehicles require high efficiency, high power density, high reliability, low noise and low cost. Multiphase motors are one of the technical means to achieve this requirement. Among them, six-phase motors can offset specific order harmonics, reduce torque pulsation, and improve motor NVH (Noise, Vibration, Harshness) performance compared to three-phase motors.

However, for permanent magnet synchronous motors, the rotor magnetic field is constant, the motor flux cannot change, and as the motor speed increases, the motor back electromotive force will also increase. When the motor back electromotive force is close to the external voltage, the motor speed cannot continue to increase, and the D-axis current needs to be increased for magnetic field weakening and speed expansion, resulting in a decrease in motor efficiency.

Utility Model Content

The present application provides a motor circuit and a vehicle, which can improve the efficiency of the motor.

One aspect of the present application provides a motor circuit, comprising:

A motor, comprising a multi-phase winding, wherein at least two phase windings of the multi-phase winding are connected to form a neutral point, and the number of the neutral points is at least two; and

A switch circuit is connected between at least two of the neutral points and is used to control the on/off of the line between the neutral points; when the motor is in a first speed state, the switch circuit is in a first state, and the switch circuit disconnects the line between the neutral points; when the motor is in a second speed state, the switch circuit is in a second state, and the switch circuit connects the line between the neutral points.

The motor circuit of the present application controls the state of the motor by adding a switching circuit connected between the neutral points. It can control the number of motor phases and the size of the motor magnetic flux at different speeds to improve the efficiency and torque density of the motor.

Furthermore, the switching circuit includes at least one control switch, which is connected between two adjacent neutral points; the motor circuit includes a controller, which is connected to the control switch and is used to control the on and off of the control switch according to the state of the motor.

Furthermore, the motor circuit includes a drive circuit connected to the winding for driving the motor to operate; the drive circuit includes a plurality of inverter circuits, each of which is connected to one phase of the winding.

Further, the motor includes a six-phase motor, the winding includes a six-phase winding, each two phases of the winding are connected to form a first neutral point, a second neutral point and a third neutral point, the first neutral point, the second neutral point and the third neutral point are all connected to the switching circuit; when the switching circuit is in the first state, the switching circuit disconnects the line between the first neutral point, the second neutral point and the third neutral point; when the switching circuit is in the second state, the switching circuit connects the line between the first neutral point, the second neutral point and the third neutral point.

Furthermore, the switching circuit includes a first control switch and a second control switch, the first control switch is connected between the first neutral point and the second neutral point, the second control switch is connected between the second neutral point and the third neutral point, and when the switching circuit is in the first state, the first control switch and the second control switch are both disconnected; when the switching circuit is in the second state, the first control switch and the second control switch are both closed.

Further, the first control switch comprises an IGBT tube, the collector of the first control switch is connected to the first neutral point, and the emitter of the first control switch is connected to the second neutral point; and/or

The second control switch includes an IGBT tube, the collector of the second control switch is connected to the second neutral point, and the emitter of the second control switch is connected to the third neutral point.

Furthermore, the motor circuit includes a drive circuit connected to the winding for driving the motor to work; the drive circuit includes six inverter circuits, each of which includes a first switch tube, a second switch tube, a first diode and a second diode, the first switch tube and the second switch tube connected in series are connected in parallel between the positive and negative electrodes of the power supply, the first diode and the first switch tube are connected in parallel, the second diode and the second switch tube are connected in parallel, and the input end of each phase of the winding is connected between the first switch tube and the second switch tube.

Further, the first switch tube and the second switch tube both comprise an IGBT tube, the collector of the first switch tube is connected to the positive electrode of the power supply, the emitter of the first switch tube is connected to the collector of the second switch tube, and the emitter of the second switch tube is connected to the negative electrode of the power supply; the cathode of the first diode is connected to the collector of the first switch tube, and the anode of the first diode is connected to the emitter of the first switch tube; the cathode of the second diode is connected to the collector of the second switch tube, and the anode of the second diode is connected to the emitter of the second switch tube;

When the switching circuit is in the first state, the first switching tube in the inverter circuit connected to one of the two-phase windings forming the neutral point is disconnected, and the second switching tube in the inverter circuit is closed; when the switching circuit is in the second state, the first switching tube in the inverter circuit connected to one of the two-phase windings forming the neutral point is closed, and the second switching tube in the inverter circuit is disconnected.

Furthermore, it also includes a voltage stabilizing capacitor connected in parallel with the power supply.

Another aspect of the present application provides a vehicle, comprising:

Power supply; and

The motor circuit described in any of the above items is connected to the power supply.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

FIG1 is a circuit diagram of an embodiment of a motor circuit of the present application;

FIG. 2 is a schematic diagram showing the connection of motor windings in the motor circuit shown in FIG. 1 .

Detailed ways

Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantitative limit, but indicate that there is at least one. "Multiple" or "several" means at least two. Unless otherwise specified, words such as "front", "rear", "lower" and/or "upper" are only for the convenience of explanation and are not limited to a position or a spatial orientation. Words such as "include" or "comprise" mean that the elements or objects appearing in front of "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, and can include electrical connections, whether direct or indirect.

The singular forms "a", "said" and "the" used in this specification and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

The motor circuit includes a motor and a switch circuit. The motor includes a multi-phase winding, at least two phase windings of the multi-phase winding are connected to form a neutral point, and there are at least two neutral points. The switch circuit is connected between at least two neutral points and is used to control the on and off of the line between the neutral points; when the motor is in a first speed state, the switch circuit is in a first state, and the switch circuit disconnects the line between the neutral points; when the motor is in a second speed state, the switch circuit is in a second state, and the switch circuit connects the line between the neutral points.

The motor circuit of the present application controls the state of the motor by adding a switching circuit connected between the neutral points. It can control the number of motor phases and the size of the motor magnetic flux at different speeds to improve the efficiency and torque density of the motor.

The vehicle provided in the present application includes a power supply and a motor circuit, and the motor circuit is connected to the power supply.

The motor circuit and vehicle of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

The motor circuit of the embodiment of the present application can be applied to vehicles, mainly to new energy vehicles, including pure electric vehicles, hybrid vehicles, plug-in hybrid vehicles and other vehicles that use on-board power batteries as the main power source or one of the power sources. The vehicle may include a power supply and a motor circuit, and the motor circuit is connected to the power supply. Among them, the motor circuit may include a motor, and the power supply and the motor are connected to provide a power source for the motor to work.

The motor circuit of the embodiment of the present application includes a motor and a switch circuit. The motor includes a multi-phase winding, at least two phase windings of the multi-phase winding are connected to form a neutral point, and there are at least two neutral points. The switch circuit is connected between at least two neutral points and is used to control the on and off of the line between the neutral points; when the motor is in a first speed state, the switch circuit is in a first state, and the switch circuit disconnects the line between the neutral points; when the motor is in a second speed state, the switch circuit is in a second state, and the switch circuit connects the line between the neutral points.

The motor circuit of the present application controls the state of the motor by adding a switching circuit connected between the neutral points. It can control the number of motor phases and the size of the motor magnetic flux at different speeds to improve the efficiency and torque density of the motor.

It should be noted that the first speed state of the motor is the low-speed operation state of the motor, and the second speed state of the motor is the high-speed operation state of the motor. This application does not specifically define the above-mentioned "low speed" and "high speed", and can be adjusted according to the actual working conditions of the motor. The motor in the embodiment of the present application can be a multi-phase motor, including but not limited to a six-phase motor and a twelve-phase motor. It can be understood that the six-phase motor includes a six-phase winding, and the twelve-phase motor includes a twelve-phase winding. Of course, motors with other numbers of phases are also within the protection scope of this application and will not be repeated.

In some embodiments, the motor circuit may further include a controller connected to the motor. The controller may monitor the motor speed and rotor position in real time through the motor's rotary transformer and calculate the motor's magnetic flux size.

In some embodiments, the switch circuit includes at least one control switch, and the control switch is connected between two adjacent neutral points. The controller is connected to the control switch and is used to control the on and off of the control switch according to the state of the motor. The controller obtains the speed and rotor position of the motor, and after calculating the magnetic flux of the motor, determines the operating state of the motor. When the motor is working at a low speed, the number of phases of the motor is reduced by controlling the state of the control switch. At this time, the magnetic flux of the motor is strong, the back electromotive force is increased, and the peak torque is higher under the same current. When the motor speed increases to a certain value, the number of phases of the motor is increased by adjusting the conduction state of the control switch. At this time, the magnetic flux of the motor is reduced, and the back electromotive force of the motor is reduced. The motor does not need weak magnetic field to increase the speed, the reactive current is reduced, and the efficiency of the motor is improved. At the same time, due to the increase in the number of phases of the motor, the torque of the motor can still maintain a high output.

In some embodiments, the motor circuit includes a drive circuit connected to the winding for driving the motor to work. Specifically, the drive circuit may include a plurality of inverter circuits, each of which is connected to a phase winding. The inverter circuit, i.e., an inverter bridge, an inverter, can convert the DC voltage provided by the power supply into an AC voltage. Specifically, in an embodiment where the motor is a six-phase motor, the drive circuit includes six inverter circuits, i.e., a six-phase inverter bridge; in an embodiment where the motor is a twelve-phase motor, the drive circuit includes twelve inverter circuits, i.e., a twelve-phase inverter bridge.

Specifically, the inverter circuit may include a first switch tube, a second switch tube, a first diode and a second diode, the first switch tube and the second switch tube connected in series are connected in parallel between the positive and negative electrodes of the power supply, the first diode is connected in parallel with the first switch tube, the second diode is connected in parallel with the second switch tube, and the input end of each phase winding is connected between the first switch tube and the second switch tube. Further, the first switch tube and the second switch tube both include an IGBT tube, the collector of the first switch tube is connected to the positive electrode of the power supply, the emitter of the first switch tube is connected to the collector of the second switch tube, and the emitter of the second switch tube is connected to the negative electrode of the power supply; the cathode of the first diode is connected to the collector of the first switch tube, and the anode of the first diode is connected to the emitter of the first switch tube; the cathode of the second diode is connected to the collector of the second switch tube, and the anode of the second diode is connected to the emitter of the second switch tube.

FIG1 is a circuit diagram of an embodiment of a motor circuit of the present application. In an embodiment where the motor is a six-phase motor, each two-phase winding is connected to form a first neutral point N1, a second neutral point N2, and a third neutral point N3. The first neutral point N1, the second neutral point N2, and the third neutral point N3 are all connected to the switch circuit. When the switch circuit is in a first state, the switch circuit disconnects the line between the first neutral point N1, the second neutral point N2, and the third neutral point N3. When the switch circuit is in a second state, the switch circuit connects the line between the first neutral point N1, the second neutral point N2, and the third neutral point N3. Specifically, in this embodiment, the six-phase winding of the motor includes a first winding, a second winding, a third winding, a fourth winding, a fifth winding, and a sixth winding. The output ends of the first winding and the second winding are connected to form a first neutral point N1; the output ends of the third winding and the fourth winding are connected to form a second neutral point N2, and the output ends of the fifth winding and the sixth winding are connected to form a third neutral point N3.

FIG. 2 is a schematic diagram of the connection of the motor windings in the motor circuit shown in FIG. 1. FIG. 2 shows a 24-slot 6-phase motor. As shown in FIG. 2, the motor of the embodiment of the present application is a motor with a variable number of phases and a Y-connected winding. Its output wires require 9 wires, which are represented by A, a, B, b, C, c, N1, N2, and N3 respectively. A, a, B, b, C, and c represent the six phases of the motor, and N1, N2, and N3 represent the neutral point lead wires of the motor.

Specifically, the selection of the number of stator slots (Z) of the motor needs to satisfy the following relationship:

Z÷3＝2*N

Where N = 1, 2, 3...

Continuing to refer to Figure 2, the stator windings of each phase in the motor circuit of the embodiment of the present application need to be connected in a specific manner. In the related art, the output ends of the windings of each phase are connected to form a neutral point inside the motor. In the motor circuit of the embodiment of the present application, the output ends of the windings of each phase are connected inside the motor and then led out in the form of lead wires. Specifically, the output ends of phase A and phase a are connected inside the motor and then led out in the form of lead wires to a first neutral point, represented by N1; similarly, the output ends of phase B and phase b lead out a second neutral point, represented by N2; the output ends of phase C and phase c lead out a third neutral point, represented by N3.

On the basis of the above embodiment, the switch circuit includes a first control switch Q13 and a second control switch Q14, the first control switch Q13 is connected between the first neutral point N1 and the second neutral point N2, the second control switch Q14 is connected between the second neutral point N2 and the third neutral point N3, when the switch circuit is in the first state, the first control switch Q13 and the second control switch Q14 are both disconnected; when the switch circuit is in the second state, the first control switch Q13 and the second control switch Q14 are both closed. It can be understood that the windings of the motor are divided into three groups on the basis of the six-phase motor, and the adjacent two-phase windings are a group, called a large phase, and the two windings in the large phase are connected to form a neutral point, and the neutral points are connected using control switches.

The first control switch Q13 may include an IGBT tube. Specifically, the collector of the first control switch Q13 is connected to the first neutral point N1, and the emitter of the first control switch Q13 is connected to the second neutral point N2. The second control switch Q14 may also include an IGBT tube. Specifically, the collector of the second control switch Q14 is connected to the second neutral point N2, and the emitter of the second control switch Q14 is connected to the third neutral point N3. The IGBT tube is an insulated gate bipolar transistor, which has the characteristics of high power density, high efficiency, reliability, and easy control.

In some embodiments, the motor circuit includes a drive circuit connected to the winding for driving the motor to work. The drive circuit includes six inverter circuits. As described above, each inverter circuit includes a first switch tube, a second switch tube, a first diode and a second diode. The first switch tube and the second switch tube connected in series are connected in parallel between the positive and negative electrodes of the power supply BT1. The first diode and the first switch tube are connected in parallel, and the second diode and the second switch tube are connected in parallel. The input end of each phase winding is connected between the first switch tube and the second switch tube. Optionally, the first diode and the second diode may include a freewheeling diode.

On the basis of the above embodiment, the first switch tube and the second switch tube both include an IGBT tube, the collector of the first switch tube is connected to the positive electrode of the power supply BT1, the emitter of the first switch tube is connected to the collector of the second switch tube, and the emitter of the second switch tube is connected to the negative electrode of the power supply BT1; the cathode of the first diode is connected to the collector of the first switch tube, and the anode of the first diode is connected to the emitter of the first switch tube; the cathode of the second diode is connected to the collector of the second switch tube, and the anode of the second diode is connected to the emitter of the second switch tube.

Specifically, the drive circuit includes a first inverter circuit, a second inverter circuit, a third inverter circuit, a fourth inverter circuit, a fifth inverter circuit and a sixth inverter circuit. As shown in FIG1, the first inverter circuit includes a first switch tube Q1, a second switch tube Q2, a first diode D1 and a second diode D2. The second inverter circuit includes a first switch tube Q3, a second switch tube Q4, a first diode D3 and a second diode D4. The third inverter circuit includes a first switch tube Q5, a second switch tube Q6, a first diode D5 and a second diode D6. The fourth inverter circuit includes a first switch tube Q7, a second switch tube Q8, a first diode D7 and a second diode D8. The fifth inverter circuit includes a first switch tube Q9, a second switch tube Q10, a first diode D9 and a second diode D10. The sixth inverter circuit includes a first switch tube Q11, a second switch tube Q12, a first diode D11 and a second diode D12. The specific connection relationship is shown in FIG1 and will not be repeated.

In some embodiments, the motor circuit also includes a voltage-stabilizing capacitor C1 connected in parallel with the power supply BT1, which is connected between the positive and negative poles of the power supply BT1 and can play a filtering role to eliminate high-frequency noise and interference, thereby improving the anti-interference ability of the motor circuit.

The specific control process of the motor circuit in the embodiment of the present application is as follows:

When the motor runs at low speed, the switch circuit is in the first state, and the controller controls the first switch tube Q3, the first switch tube Q7, the first switch tube Q11, the first control switch Q13 and the second control switch Q14 to be disconnected, and controls the second switch tube Q4, the second switch tube Q8 and the second switch tube Q12 to be closed. At this time, the motor is a three-phase motor, the magnetic flux of the motor is large, and the back electromotive force of the motor is high, which can support the large torque output of the motor.

As the motor speed increases, the back electromotive force of the motor also increases. When the back electromotive force of the motor is equal to the battery voltage, in order to continue to increase the speed of the motor, the magnetic flux of the motor needs to be reduced. In the related art, the reverse magnetic field can be generated by increasing the D-axis current of the motor and using the stator of the motor to offset the magnetic field generated by the permanent magnet of the rotor; however, the increase in reactive current will increase the copper loss of the motor, which will reduce the efficiency of the motor. The motor circuit of the embodiment of the present application can control the switch circuit to be in the second state at this time, that is, the first control switch Q13 and the second control switch Q14 are closed by the controller, and the switch states of the first switch tube Q3, the first switch tube Q7, the first switch tube Q11, the second switch tube Q4, the second switch tube Q8 and the second switch tube Q12 are adjusted at the same time, and the motor is changed from a three-phase motor to a six-phase motor. At this time, the number of windings of each phase winding becomes half of the original, and the magnetic flux is also reduced to half of the original, the back electromotive force of the motor is reduced, the motor no longer needs weak magnetic field to expand the speed, and the efficiency of the motor is improved. Under normal circumstances, due to the increase in frequency in the high-speed stage, the sinusoidality of the SVPWM wave generated by the power supply BT1 decreases, the motor air gap harmonics increase, and the NVH effect of the motor deteriorates; after adjusting to a six-phase motor, the order of the spatial harmonic magnetomotive force generated by the motor fundamental current increases, the input torque pulsation of the motor decreases, and the NVH performance of the motor is optimized.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims (10)

1.A motor circuit, comprising:

the motor comprises a multi-phase winding, wherein at least two phase windings in the multi-phase winding are connected to form a neutral point, and the number of the neutral points is at least two; and

The switching circuit is connected between at least two neutral points and used for controlling the on-off of a circuit between the neutral points; when the motor is in a first rotating speed state, the switch circuit is in a first state, and the switch circuit breaks a line between the neutral points; when the motor is in a second rotating speed state, the switch circuit is in a second state, and the switch circuit is communicated with a line between neutral points.

2. The motor circuit of claim 1, wherein the switching circuit comprises at least one control switch connected between adjacent two of the neutral points; the motor circuit comprises a controller, wherein the controller is connected with the control switch and is used for controlling the on-off of the control switch according to the state of the motor.

3. The motor circuit of claim 1, wherein the motor circuit includes a drive circuit coupled to the windings for driving the motor in operation; the driving circuit comprises a plurality of inverter circuits, and each inverter circuit is connected with one phase of winding.

4. The motor circuit of claim 1, wherein the motor comprises a six-phase motor, the windings comprise six-phase windings, each two phases of the windings being connected to form a first neutral point, a second neutral point, and a third neutral point, the first neutral point, the second neutral point, and the third neutral point being connected to the switching circuit; when the switching circuit is in the first state, the switching circuit breaks a line between the first neutral point, the second neutral point and the third neutral point; when the switch circuit is in the second state, the switch circuit is communicated with a line among the first neutral point, the second neutral point and the third neutral point.

5. The motor circuit of claim 4, wherein the switching circuit includes a first control switch and a second control switch, the first control switch being connected between the first neutral point and the second neutral point, the second control switch being connected between the second neutral point and the third neutral point, the first control switch and the second control switch both being open when the switching circuit is in the first state; when the switch circuit is in the second state, the first control switch and the second control switch are both closed.

6. The motor circuit of claim 5, wherein the first control switch comprises an IGBT tube, a collector of the first control switch is connected to the first neutral point, and an emitter of the first control switch is connected to the second neutral point; and/or

The second control switch comprises an IGBT tube, the collector electrode of the second control switch is connected with the second neutral point, and the emitter electrode of the second control switch is connected with the third neutral point.

7. The motor circuit of claim 5, wherein the motor circuit includes a drive circuit coupled to the windings for driving the motor in operation; the driving circuit comprises six inverter circuits, each inverter circuit comprises a first switch tube, a second switch tube, a first diode and a second diode, the first switch tube and the second switch tube which are connected in series are connected in parallel between the positive electrode and the negative electrode of a power supply, the first diode and the first switch tube are connected in parallel, the second diode and the second switch tube are connected in parallel, and the input end of each phase of winding is connected between the first switch tube and the second switch tube.

8. The motor circuit of claim 7, wherein the first switching tube and the second switching tube each comprise an IGBT tube, a collector of the first switching tube is connected to a positive pole of the power supply, an emitter of the first switching tube is connected to a collector of the second switching tube, and an emitter of the second switching tube is connected to a negative pole of the power supply; the cathode of the first diode is connected with the collector of the first switching tube, and the anode of the first diode is connected with the emitter of the first switching tube; the cathode of the second diode is connected with the collector of the second switching tube, and the anode of the second diode is connected with the emitter of the second switching tube;

When the switching circuit is in the first state, a first switching tube in the inverter circuit connected with one of the two phase windings forming the neutral point is opened, and a second switching tube in the inverter circuit is closed; when the switching circuit is in the second state, a first switching tube in the inverter circuit connected to one of the two phase windings forming the neutral point is closed, and a second switching tube in the inverter circuit is opened.

9. The motor circuit of claim 1, further comprising a voltage stabilizing capacitor connected in parallel with the power supply.

10. A vehicle, characterized by comprising:

A power supply; and

The motor circuit of any one of claims 1-9, connected to the power supply.