CN108429499B - Self-excitation High speed SRM power converter system - Google Patents

Abstract

Self-excitation High speed SRM power converter system, it is formed in parallel by multiple power conversion branches and output capacitor, compared with the prior art, its structure is very simple, every phase winding is only by a switch controlled, it is easy to control, and the power conversion branch structure of every phase winding is identical, scalability is strong, when certain phase winding works, the switching tube closure conducting excitation of power conversion branch where it first, is shifted magnetic energy by a transformer after disconnection and is exported, while the simple structure and control can according to need power generation or the operation of electronic operating condition；In addition, respectively power conversion branch works independently, is worked at the same time to be suitable for two-phase winding, enrich switched reluctance machines operational mode；Each volume of transformer weight is reduced under the conditions of high-speed cruising, that is, high frequency conversion；So be very suitable to the switched reluctance motor system application of all kinds of small power high speeds operation, for example fields such as aero dynamo, automobile current generator, field construction power generation/power driven system.

Description

Self-excited high-speed switched reluctance motor power converter system

technical field

The invention relates to the field of switched reluctance motors, in particular to a self-excited structure switched reluctance motor power converter suitable for low-power high-speed operation and a control method thereof.

Background technique

The structure of the switched reluctance motor is simple and strong, there is no winding on the rotor, no permanent magnet, the heat dissipation pressure is small, the reliability is high, and the manufacturing cost is low. The failure of one phase winding does not affect the normal operation of the other phase windings. It has strong fault tolerance and broad application potential. application prospects.

Switched reluctance motors generally have multiple phase windings symmetrically distributed on the salient poles of the stator. The phase windings that are energized are determined according to the relative positions of the salient poles and grooves between the stator and rotor. Work; when working as a generator, each phase winding is generally divided into two stages: excitation and power generation. The excitation is first energized before and after the maximum inductance area of the winding. The rotor position information ends the excitation stage and the commutation enters the power generation stage. The magnetic energy stored in the phase winding is converted into electric energy output. When it enters the minimum winding inductance area, the current drops to zero to complete the work. If necessary, a freewheeling stage is introduced in the middle to improve the power generation stage. Initial current; when working as a motor, the main body of each phase winding is the excitation stage. When the winding inductance is the smallest area or the inductance rises, the excitation is energized. After entering the winding inductance maximum area, the excitation is turned off to complete the work. If necessary, the excitation ends. Finally, a freewheeling circuit is provided to release the residual magnetic energy in the winding.

The excitation, freewheeling and power generation of the switched reluctance motor must be realized around the operation control of the conversion circuit connected to its winding. Without the winding conversion circuit, the operation of the switched reluctance motor cannot be discussed, so the converter is of great significance.

When the switched reluctance generator is running, the existing converter system, in the excitation stage, many excitation power sources have realized the self-excitation mode, so that there is no need for manual work of frequent battery replacement or charging in the separate excitation mode, but many existing self-excitation modes The mode of increasing the excitation circuit is selected. Although the excitation is variable, it increases the complexity of the structure and control, especially in some fields where the maximum power output is not the primary requirement.

The most typical power converter circuit of the current switched reluctance motor is an asymmetrical half-bridge structure, which has obvious advantages and is widely used in the industry, but the converter main circuit of this structure uses too many switching devices.

Quite a lot of new power converter circuits that appear at present cannot adapt to the occasions where more than one phase windings work at the same time, and considering the overall efficiency of the motor, in fact, the magnetic pole overlap coefficient of most existing switched reluctance motors is low. is greater than zero, that is to say, when working according to the rotor position information standard, there are often more than one phase windings working at the same time, especially for switched reluctance motors greater than or equal to four-phase windings, multi-phase windings work at the same time, For example, when one phase is excited and the other phase generates power, etc., it is of great practical significance to consider this point in the design of the power converter.

In some application fields of switched reluctance motor systems, such as high-speed aviation motors, automobile generators, power generation and electric drive in outdoor areas without power supply, etc., it is necessary to perform power generation and electric operation at different times according to different needs, then , a set of power converters can adapt to the different working conditions of power generation and electric motoring at the same time, it will inevitably reduce the system cost, reduce the volume and weight, especially if the control mode is close, because the controller does not need to be complicated, it is bound to have a wide range of prospects.

Contents of the invention

According to the above background technology, the present invention proposes a high-speed switched reluctance motor power converter with only one switch tube for each phase winding, modularized and scalable independent working conversion branch, which can take into account both power generation and electric working conditions. and its control methods.

Technical scheme of the present invention is:

The self-excited high-speed switched reluctance motor power converter system is composed of a first power conversion branch, a second power conversion branch, a third power conversion branch, and a capacitor, and its technical feature is that the first power conversion branch , the second power conversion branch, the third power conversion branch, and the capacitor are all connected in parallel;

The first power conversion branch is composed of a first phase winding, a first switch tube, a first diode, a second diode, and a first transformer, and its technical feature is that one end of the first phase winding and the first The anode of the switching tube is connected to one end of the primary side winding of the first transformer, and the other end of the first phase winding is connected to the cathode of the first diode, the cathode of the second diode, the anode of the second power conversion branch, the third The positive pole of the power conversion branch is connected to the positive pole of the capacitor, and is used as the positive pole of the first power conversion branch. The anode of the first diode is connected to the other end of the primary side winding of the first transformer, and the anode of the second diode is connected to the secondary side of the first transformer. One end of the winding is connected, and the other end of the secondary side winding of the first transformer is connected to the cathode of the first switch tube, the negative pole of the second power conversion branch, the negative pole of the third power conversion branch, and the negative pole of the capacitor, and is used as the negative terminal of the first power conversion branch ;

The internal structure of the second power conversion branch and the third power conversion branch are exactly the same as the internal structure of the first power conversion branch, and their second switching tube and third switching tube correspond to the first switching tube, and the second phase winding , The third phase winding corresponds to the first phase winding, the second transformer and the third transformer correspond to the first transformer, the third diode and the fifth diode correspond to the first diode, the fourth diode, the sixth and second The pole tube corresponds to the second diode, and the corresponding devices are identical;

The primary side winding and the secondary side winding of the first transformer, the second transformer, and the third transformer have opposite polarities, and the ratio of turns is 1.

The control method of the self-excited high-speed switched reluctance motor power converter system of the present invention is as follows: all the switch tubes in the power converter of the present invention are fast full-control type power electronic three-terminal devices, and the initial states are all disconnected states; all switches The control of the tube is realized by a special controller according to the output of the detection signal;

When the switched reluctance motor is running as a generator, according to the operating principle of the switched reluctance generator, combined with the rotor position information, when it is detected that the first phase winding needs to be energized to work, the first switch tube is first closed and turned on, and the power supply at both ends of the capacitor Supply power to the first phase winding for excitation. This is the excitation phase. When the excitation phase ends according to the rotor position information, the first switch tube is turned off, and the magnetic energy stored in the first phase winding flows through the first diode through the primary side of the first transformer. winding, and coupled with the secondary side winding of the first transformer, the capacitor is charged and output through the second diode output; the working principle of the power conversion branch where the other phase windings are located is the same, and will not be described again;

When the switched reluctance motor operates as a motor, according to the operating principle of the switched reluctance motor, combined with the rotor position information under the motor working condition, the switching action of the only switching tube of each power conversion branch is performed, which is the same as the control mode of the generator working condition , only the rotor position point of the specific switch action is different, so when it is running as a motor, because the magnetic energy of the corresponding phase winding is released after the excitation power supply is completed and fed back to the power supply, it has the function of energy regeneration.

Technical effect of the present invention mainly contains:

(1) In the power converter circuit of the present invention, only one switching tube is needed for each phase winding, which simplifies the structure, reduces the control complexity, and reduces the burden on the controller.

(2) Modular structure, the power conversion branches where the windings of each phase are located can work independently without interfering with each other, thus adapting to the occasion where the power conversion branches where the two-phase windings are located work at the same time, and has strong scalability.

(3) The present invention is especially aimed at high-speed switched reluctance motors. Each transformer works at high frequency, which will inevitably reduce the volume and weight of the transformers and save costs, especially in long-term high-speed switched reluctance motor systems.

(4) It adapts to the working conditions of the generator and the motor at the same time, the control mode is the same, the requirements for the controller are relatively low, and the reliability is high.

Description of drawings

Fig. 1 shows the structure diagram of the self-excited high-speed switched reluctance motor power converter system of the present invention.

Detailed ways

As shown in Figure 1, the three-phase winding switched reluctance motor power converter of this embodiment is composed of a first power conversion branch 1, a second power conversion branch 2, a third power conversion branch 3, and a capacitor C. The first power conversion branch 1, the second power conversion branch 2, the third power conversion branch 3, and the capacitor C are all connected in parallel; runtime) at both ends of the connection;

The first power conversion branch 1 is composed of the first phase winding M, the first switching tube V1, the first diode D1, the second diode D2, and the first transformer T1. One end of the first phase winding M and the first switch The anode of the tube V1 is connected to one end of the primary side winding a of the first transformer T1, and the other end of the first phase winding M is connected to the cathode of the first diode D1, the cathode of the second diode D2, the anode of the second power conversion branch 2, and the third The positive pole of the power conversion branch 3 is connected to the positive pole of the capacitor C, and serves as the positive pole of the first power conversion branch 1, the anode of the first diode D1 is connected to the other end of the primary side winding a of the first transformer T1, and the anode of the second diode D2 It is connected to one end of the secondary side winding b of the first transformer T1, and the other end of the secondary side winding b of the first transformer T1 is connected to the cathode of the first switching tube V1, the negative pole of the second power conversion branch 2, the negative pole of the third power conversion branch 3, The negative pole of the capacitor C is connected, and serves as the negative pole of the first power conversion branch 1;

The internal structure of the second power conversion branch 2 and the third power conversion branch 3 is exactly the same as that of the first power conversion branch 1, and their second switching tube V2 and third switching tube V3 correspond to the first switching tube V1, the second phase winding N and the third phase winding P correspond to the first phase winding M, the second transformer T2 and the third transformer T3 correspond to the first transformer T1, the third diode D3 and the fifth diode D5 correspond to the first phase winding One diode D1, the fourth diode D4, and the sixth diode D6 correspond to the second diode D2, and the corresponding devices are identical; all the switch tubes are IGBT or GTR or power MOSFET or silicon carbide or nitrogen GaN devices;

The primary side windings and secondary side windings of the first transformer T1 , the second transformer T2 , and the third transformer T3 have opposite polarities, and the ratio of turns is 1.

The control method of the self-excited high-speed switched reluctance motor power converter system of the present invention is as follows: the initial state of all the switch tubes in the power converter is in the disconnected state; the control of all the switch tubes is realized by a special controller according to the output of the detection signal ;

When the switched reluctance motor operates as a generator, according to the operating principle of the switched reluctance generator, combined with the rotor position information, when it is detected that the first phase winding M needs to be energized to work, the first switch tube V1 is first turned on, and the capacitor C The power supply at both ends supplies power to the first phase winding M for excitation. The circuit is C-M-V1-C. This is the excitation stage. When the excitation stage ends according to the rotor position information, the first switch tube V1 is disconnected, and the stored in the first phase winding M The magnetic energy flows through the first diode D1 through the primary side winding a of the first transformer T1, and is coupled with the secondary side winding b of the first transformer T1, and then output through the second diode D2 to charge and output the capacitor C. The circuits are respectively : M-a-D1-M, b-D2-C-b; the working principle of the power conversion branch where the other phase windings are located is the same as this, and will not be repeated here; since the power conversion branch where each phase winding is located and other power conversion branches They do not interfere with each other, so they can work at the same time. According to the rotor position information, generally, the overlap coefficient of the salient poles of the stator and rotor is greater than zero, that is, there are two phase windings working at the same time, such as the excitation phase of one phase winding and the power generation phase of adjacent phase windings.

When the switched reluctance motor operates as a motor, according to the operating principle of the switched reluctance motor, combined with the rotor position information under the motor working condition, the switching action of the only switching tube of each power conversion branch is performed, which is the same as the control mode of the generator working condition , only the rotor position point of the specific switch action is different, so when it is running as a motor, because the magnetic energy of the corresponding phase winding is released after the excitation power supply is completed and fed back to the power supply, it has the function of energy regeneration.

When operating as a motor and generator, the rated speed is 30,000 rpm, the switched reluctance motor is a three-phase 12/8 structure, high-speed operation, higher frequency commutation and commutation work, so that each transformer works at high frequency, which can Reduce volume weight and reduce cost.

Claims (2)

1. encourage oneself High speed SRM power converter system, by the first power conversion branch, the second power conversion branch, Third power conversion branch, capacitor composition, technical characteristic are that the first power conversion branch, second power become It changes branch, the third power conversion branch, be connected in parallel between the capacitor；

First power conversion branch routes the first phase winding, first switch tube, first diode, the second diode, the first transformer Composition, first phase winding one end are connected with the first switch tube anode, first transformer primary winding one end, The first phase winding other end and the first diode cathode, second diode cathode, the second power conversion branch anode, Third power conversion branch anode, capacitor anode connection, and as the first power conversion branch anode, first diode anode It is connect with the first transformer primary winding other end, the second diode anode and first Circuit Fault on Secondary Transformer winding one end connect It connects, the first Circuit Fault on Secondary Transformer winding other end and first switch tube cathode, the second power conversion branch cathode, third power become Branch cathode, capacitor anode connection are changed, and as the first power conversion branch negative pole end；

Second power conversion branch and the internal structure of third power conversion branch and the first power conversion branch internal structure are complete It is exactly the same, and their second switch, third switching tube correspond to first switch tube, the second phase winding, third phase winding pair Answer the first phase winding, corresponding first transformer of the second transformer, third transformer, third diode, the 5th diode pair answer the One diode, the 4th diode, the 6th diode pair answer the second diode, and corresponding device is identical；

First transformer, the second transformer, the respective first side winding of third transformer and secondary side winding polarity is opposite, the number of turns The ratio between be 1.

2. the control method of self-excitation High speed SRM power converter system according to claim 1 are as follows: power All switching tubes are quick full-control type power electronic three terminal device in converter, and original state is off-state；It is all to open The control for closing pipe is realized by special controller according to detection signal output；

When switched reluctance machines are run as generator, according to switch reluctance generator operation logic, believe in conjunction with rotor-position Breath, when detecting that the first phase winding need to be powered on, closure conducting first switch tube first, capacitor both ends power supply is to first For phase winding for electrical excitation, this is the excitation stage, at the end of the rotor position information excitation stage, disconnects first switch tube, the The magnetic energy stored in one phase winding flows through the first transformer primary winding through first diode, and with the first Circuit Fault on Secondary Transformer It is exported after winding coupled through the second diode and charges and export to capacitor；The work of power conversion branch where remaining phase winding Principle is identical with this；

When switched reluctance machines are as motor running, according to switched reluctance motor operation logic, in conjunction with motor working condition Lower rotor part location information carries out the switch motion of each power conversion branch unique one pipe, with control mould when generator operating condition Formula is identical, and the rotor-position point of only specific switch motion is different, thus when as motor running, after excitation power supply The accordingly release of phase winding magnetic energy and feedback power, so having energy regeneration function.