CN112152541B

CN112152541B - Switched reluctance motor controller and energy flow control method thereof

Info

Publication number: CN112152541B
Application number: CN202010813046.0A
Authority: CN
Inventors: 周广旭; 朱孟美; 宋宁冉; 慕永云; 高佳; 郭磊
Original assignee: Institute of Automation Shandong Academy of Sciences
Current assignee: Institute of Automation Shandong Academy of Sciences
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2022-06-07
Anticipated expiration: 2040-08-13
Also published as: CN112152541A

Abstract

The invention belongs to the field of motor control, and provides a switched reluctance motor controller and an energy flow control method thereof. The switched reluctance motor controller comprises a power conversion circuit, wherein the input end of the power conversion circuit is connected with a direct current power supply, and the output end of the power conversion circuit is connected with an energy storage capacitor; the power conversion circuit comprises a first energy control branch, a second energy control branch and a follow current branch, wherein the first energy control branch is used for controlling the energy of the direct-current power supply to be transferred to the motor winding, the second energy control branch is used for controlling the energy of the energy storage capacitor to be transferred to the motor winding, and the follow current branch is used for enabling the current of the motor winding to follow current when the first energy control branch and the second energy control branch are disconnected; and the energy storage capacitor is used for storing energy in the direct current power supply and the motor winding, and releasing the stored energy to the motor winding to keep the current of the motor winding constant when the energy of the direct current power supply is lower than a preset threshold value.

Description

Switched reluctance motor controller and energy flow control method thereof

Technical Field

The invention belongs to the field of motor control, and particularly relates to a switched reluctance motor controller and an energy flow control method thereof.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

At present, the requirement of environmental protection and energy conservation needs to realize higher power factor at the input side of a motor control system. The inventors have found that existing motor controllers all require a separate active power factor circuit, which increases system cost and results in insignificant competitive advantages, especially in low power applications, which results in higher costs than other motors.

Disclosure of Invention

In order to solve the above problems, the present invention provides a switched reluctance motor controller and an energy flow control method thereof, which can realize the operation of a motor and have a source power factor correction function, thereby ensuring the normal operation of the motor and simultaneously realizing the significant improvement of the input side power factor.

In order to achieve the purpose, the invention adopts the following technical scheme:

a first aspect of the invention provides a switched reluctance motor controller.

In one or more embodiments, a switched reluctance motor controller includes:

the input end of the power conversion circuit is connected with a direct-current power supply, and the output end of the power conversion circuit is connected with the energy storage capacitor; the power conversion circuit comprises a first energy control branch, a second energy control branch and a follow current branch, wherein the first energy control branch is used for controlling the energy of the direct-current power supply to be transferred to the motor winding, the second energy control branch is used for controlling the energy of the energy storage capacitor to be transferred to the motor winding, and the follow current branch is used for enabling the current of the motor winding to follow current when the first energy control branch and the second energy control branch are disconnected;

and the energy storage capacitor is used for storing energy in the direct current power supply and the motor winding, and releasing the stored energy to the motor winding to keep the current of the motor winding constant when the energy of the direct current power supply is lower than a preset threshold value.

A second aspect of the present invention provides a control method of a switched reluctance motor controller.

A control method of a switched reluctance motor controller, comprising:

comparing the voltage of the energy storage capacitor with an operation threshold value, and judging whether to supplement energy for the energy storage capacitor through a direct-current power supply;

after the energy storage capacitor is charged, judging whether the energy of the direct current power supply meets an independent power supply condition, if so, conducting the first energy control branch, and independently supplying power to the motor winding by the direct current power supply; otherwise, the second energy control branch is also conducted, and the direct-current power supply and the energy storage capacitor jointly supply power to the motor winding.

Compared with the prior art, the invention has the beneficial effects that:

(1) the motor controller has simple topological structure, less devices and cost saving;

(2) the control strategy of the invention is easy to realize, and an expensive control chip is not needed;

(3) the invention can realize that the power supply energy and the capacitance energy reach the motor winding by adopting a simple control algorithm;

(4) the invention can independently control the energy of the power supply and the energy of the capacitor, and realize the decoupling control of the two energies on the energy of the motor winding.

(5) The invention can feed back the energy of the motor winding to the capacitor, plays a role in energy recovery and ensures that the system has higher operating efficiency.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 is a switched reluctance machine controller topology according to an embodiment of the present invention;

FIG. 2 is a flow chart of energy flow control of an embodiment of the invention

FIG. 3 illustrates a power supply charging mode for a capacitor according to an embodiment of the present invention;

FIG. 4 is a power supply exciting motor winding pattern of an embodiment of the present invention;

FIG. 5 is a freewheel mode of a motor winding according to an embodiment of the invention;

FIG. 6 illustrates a motor winding energy to capacitor charging mode in accordance with an embodiment of the present invention;

FIG. 7 is a schematic diagram of a power supply and capacitor simultaneously energizing motor winding patterns in accordance with an embodiment of the present invention;

fig. 8 is a capacitively excited motor winding pattern of an embodiment of the present invention.

Detailed Description

The invention is further described with reference to the following figures and examples.

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

In the present invention, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only terms of relationships determined for convenience of describing structural relationships of the parts or elements of the present invention, and are not intended to refer to any parts or elements of the present invention, and are not to be construed as limiting the present invention.

In the present invention, terms such as "fixedly connected", "connected", and the like are to be understood in a broad sense, and mean either a fixed connection or an integrally connected or detachable connection; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be determined according to specific situations by persons skilled in the relevant scientific or technical field, and are not to be construed as limiting the present invention.

A switched reluctance motor controller of the present embodiment includes:

Specifically, a first power switch tube, a motor winding and a third power switch tube are sequentially connected in series on the first energy control branch; and the second energy control branch is sequentially connected with a second power switch tube, a motor winding and a third power switch tube in series.

The second power switch tube is connected with the first diode in parallel.

The follow current branch comprises a first follow current branch and a second follow current branch, and a motor winding, a second diode, an energy storage capacitor and a third diode are sequentially connected in series on the first follow current branch to form a first follow current loop; the second follow current branch is connected with a motor winding, a third power switch tube and a third diode in series in sequence to form a second follow current loop.

In specific implementation, one end of the energy storage capacitor is connected to the joint of the first diode and the second diode, and the other end of the energy storage capacitor is connected to the negative electrode of the direct current power supply.

It should be noted here that the dc power source may include an ac power source and a bridge rectifier circuit for converting the ac power source into the dc power source. The direct current power supply can also be an existing direct current power supply product directly.

The following takes an example in which an ac power supply and a bridge rectifier circuit constitute a dc power supply:

the switched reluctance motor controller of the present embodiment includes:

an AC-to-DC bridge rectifier circuit converts an AC power supply into a DC power supply. The working principle of the circuit is as follows: in the positive half cycle of the power supply, D1 and D4 are turned on, D2 and D3 are turned off, and the current returns from the upper end of the power supply to the lower end of the power supply through D1 → Q1 → D4. In the negative half cycle of the power supply, D1 and D4 are turned off, D2 and D3 are turned on, and the current returns from the lower end of the power supply to the upper end of the power supply through D3 → Q1 → D2.

As shown in fig. 1, in the present embodiment, the power conversion circuit includes power switches Q1, Q2, Q3, and diodes D5, D6, D7. The power switch Q1, the motor winding and the Q3 form an energy control branch circuit, and the energy of the alternating current power supply is controlled to the motor winding. The power switch Q2, the motor winding and the Q3 form an energy control branch circuit, and the energy of the capacitor is controlled to the motor winding. Diodes D5, D6 and D7 freewheel the motor winding energy in the two steps when Q1, Q2 and Q3 are turned off.

Specifically, the energy storage capacitor stores energy in the power supply and the motor winding, and when the energy of the power supply does not meet the requirement of supplying power for the motor winding alone, the energy is released to the motor winding to keep the current of the motor winding constant.

The motor controller of the embodiment has simple topological structure, less devices and easy realization; simple control algorithms enable power supply energy and capacitor energy to the motor windings.

The working method in one working cycle of the alternating current input power supply assumes that a power switch and a diode are ideal elements: the working principle of the bridge rectifier circuit of the embodiment is as follows:

in the positive half cycle of the power supply, D1 and D4 are turned on, D2 and D3 are turned off, and the current returns from the upper end of the power supply to the lower end of the power supply through D1 → Q1 → D4. In the negative half cycle of the power supply, D1 and D4 are turned off, D2 and D3 are turned on, and the current returns from the lower end of the power supply to the upper end of the power supply through D3 → Q1 → D2.

As shown in fig. 2, after the system is started, the operation control process of the motor controller in this embodiment is as follows:

step one, judging whether the voltage of the energy storage capacitor is larger than a set voltage threshold of the energy storage capacitor, if not, charging is needed, Q1 is conducted, and energy is supplemented to the capacitor through a power supply, as shown in FIG. 3; if so, jump to the third step.

As shown in fig. 3, the power switch Q1 is turned on, and the current branch 1 passes through the diode D1, the power switch Q1, the diode D5, the anode of the energy storage capacitor, the cathode of the energy storage capacitor, and the diode D4 to form a loop 1. The current branch 2 forms a loop 2 through a diode D1, a power switch Q1, a motor winding, a diode D6, an energy storage capacitor anode, an energy storage capacitor cathode and a diode D4. In this process, the power supply charges the energy storage capacitor C through the above-mentioned elements.

Step two, judging that the voltage of the energy storage capacitor is greater than an operation threshold, if so, finishing the charging of the capacitor, turning off Q1, and executing the third step; otherwise, the first step is continuously executed. The operating threshold is: the data may need to be modified up and down by multiplying the full-wave rectified dc value of the ac power source by a threshold factor of 0.8. The calculation formula is that the running threshold coefficient is 0.8 times the alternating voltage and then 1.414.

Thirdly, the duty ratio of the power supply side is larger than a set threshold, the set duty ratio of the set threshold is 50%, and the value can be adjusted up and down according to the requirement; the power tubes Q1 and Q3 are conducted, and the power supply independently supplies energy to the motor winding, as shown in figure 4; the fourth step is then performed. If not, executing step six.

As shown in fig. 4, power switch Q1 is on, and current is looped through diode D1, power switch Q1, the motor winding, power switch Q3, and diode D4. In this process, the power supply supplies an excitation current to the motor windings through the above-mentioned elements.

Step four, because the current of the motor winding can not change suddenly, the power tube Q1 and the power tube Q2 are required to be cut off, the power tube Q3 is required to be conducted, the motor winding continues current through the power tube Q3, and the current and the energy of the motor are continued, as shown in fig. 5; then, step five is executed.

As shown in fig. 5, power switch Q1 is off and current is looped through the motor windings, power switch Q3 and diode D7. In this process, the motor winding current freewheels through the above-mentioned elements.

Step five, because the current of the motor winding cannot change suddenly, the power tubes Q1, Q2 and Q3 are required to be cut off, the energy of the motor winding is supplemented to the capacitor, and the seventh step is skipped as shown in FIG. 6.

As shown in fig. 6, the power switches Q1, Q3 are turned off, and the current flows through the motor winding, the diode D6, the capacitor anode, the capacitor cathode, and the diode D7 to form a loop. In this process, the motor winding current freewheels through the above elements, converting energy in the motor winding into a capacitor.

Step six, the power tubes Q1, Q2 and Q3 are switched on, and the power supply and the capacitor supply energy to the motor winding together, as shown in fig. 7. And then jumps to the fourth step.

As shown in fig. 7, power switches Q1, Q3 are turned on, and current branch 1 passes through diode D1, power switch Q1, the motor winding, power switch Q3, and diode D4 to form loop 1. Current branch 2 forms loop 2 through diode D1, power switch Q2, the motor windings, power switch Q3, and diode D4. In this process, the power supply and the capacitor supply the motor winding with excitation current through the above-mentioned elements.

Step seven, judging whether an operation stop signal is received? If yes, jumping to the eighth step. If not, jumping to the third step.

Step eight, the power tubes Q2 and Q3 are switched on, and the capacitor energy is consumed through the motor winding, as shown in fig. 8. The system operation stops when the power device is turned off.

As shown in fig. 8, power switches Q2 and Q3 are turned on, and current flows through power switch Q2, the motor winding, and power switch Q3 to form a loop. In this process, the capacitor supplies an excitation current to the motor winding through the above-mentioned elements.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A switched reluctance motor controller, comprising:

the energy storage capacitor is used for storing energy in the direct current power supply and the motor winding, and when the energy of the direct current power supply is lower than a preset threshold value, the stored energy is released to the motor winding to keep the current of the motor winding constant;

when the energy of the direct current power supply does not meet the independent power supply condition, the first energy control branch circuit and the second energy control branch circuit are simultaneously conducted, and the direct current power supply and the energy storage capacitor jointly supply power for the motor winding.

2. The switched reluctance motor controller of claim 1, wherein the first energy control branch is serially connected with a first power switch tube, a motor winding and a third power switch tube in sequence; and the second energy control branch is sequentially connected with a second power switch tube, a motor winding and a third power switch tube in series.

3. The switched reluctance motor controller of claim 2 wherein the second power switch is connected in parallel with the first diode.

4. The switched reluctance motor controller of claim 1 wherein the freewheel branch comprises a first freewheel branch and a second freewheel branch, the first freewheel branch being serially connected with a motor winding, a second diode, an energy storage capacitor and a third diode in sequence to form a first freewheel loop; the second follow current branch is connected with a motor winding, a third power switch tube and a third diode in series in sequence to form a second follow current loop.

5. The switched reluctance motor controller of claim 1, wherein one end of the energy storage capacitor is connected to a junction of the first diode and the second diode, and the other end is connected to a negative electrode of the dc power supply.

6. The switched reluctance motor controller of claim 1 wherein the dc power source comprises an ac power source and a bridge rectifier circuit for converting the ac power source to a dc power source.

7. A control method of the switched reluctance motor controller according to any one of claims 1 to 6, comprising:

8. The method of claim 7, wherein it is determined that the charging of the storage capacitor is completed when the voltage of the storage capacitor is greater than the operation threshold.

9. The method of claim 7, wherein the method further comprises determining whether a shutdown signal is received, and if so, stopping operation of the power conversion circuit after energy of the energy storage capacitor is consumed by the motor winding; if not, continuing to judge the energy of the direct current power supply.

10. The method of claim 7, wherein the motor current and energy are continued through the freewheel leg while the dc power supply alone powers the motor windings.