CN108448967A - A Switched Reluctance Motor Converter System - Google Patents

Abstract

A switched reluctance motor converter system, when the switched reluctance motor operates as a generator, the first capacitor is used as an excitation power supply, the charging of the first capacitor can be realized during the power generation stage, and the duty ratio of the first switching tube is adjusted The power generation voltage can be flexibly adjusted to meet the needs of the system; when operating as a motor, it can be realized by using the same set of converter circuits, and it also has energy regeneration capabilities; the whole system has simple structure, low cost, and high reliability, and can be applied to Small and medium-sized switched reluctance generator application systems and drive systems under various loads.

Description

A Switched Reluctance Motor Converter System

technical field

The invention relates to the field of switched reluctance motor systems, in particular to a multifunctional low-power switched reluctance motor converter system and a control method thereof.

Background technique

The switched reluctance motor has a simple and solid structure, low manufacturing cost, no windings on the rotor, no permanent magnets, high reliability, and the failure of one phase winding does not affect the normal operation of the other phase windings. It has strong fault tolerance and has broad application prospects.

In theory, switched reluctance motors can be used as motors or as generators; as generators, since DC transmission has been increasingly valued by the power sector in recent years, local DC power grids have begun to take shape in some places. As a result, more and more load devices are directly powered by DC power supply, and the switched reluctance generator directly outputs DC power.

Switched reluctance motors generally have 3-5 phase windings placed on the stator, and the phase windings that are energized are determined according to the relative positions of the salient poles and grooves between the stator and rotor; when working as a generator, each phase winding is generally divided into It is two stages of excitation and power generation. In the excitation stage, the phase winding of the motor absorbs the electric energy of the external excitation power supply and stores the magnetic energy. Afterwards, the excitation stage is completed according to the position of the rotor relative to the stator and enters the power generation stage. The magnetic energy stored in the phase winding is converted into electric energy output. When necessary, With the cooperation of the structure of the converter, an unvoltage freewheeling stage can be added between the excitation and power generation stages to quickly increase the winding current.

The excitation and power generation of the switched reluctance generator must be realized around the operation control of the inverter circuit connected to its winding. Without the winding inverter circuit, the switched reluctance generator naturally has no meaning; Position regulation and different phase windings are energized and excited, so the converter is also indispensable; at present, in some power generation/electric four-quadrant hybrid systems using switched reluctance motors, the electric operation converter and the power generation operation converter They are often separated, and each adopts its own converter system, which will inevitably increase the structural complexity and control complexity of the converter system, and also increase the cost. High reliability, integrated switched reluctance generator/motor converter The system is what the industry needs.

When the switched reluctance motor operates as a generator, the existing inverter system, in the excitation stage, most of the excitation power supply has realized the self-excitation mode, but many new self-excitation power supplies have a complicated structure and need to be equipped with a special excitation inverter circuit system, and A separate control system also increases the control complexity of the system.

In practice, the DC voltage generated by the switched reluctance generator often requires a higher voltage value. In addition to taking certain measures to boost the voltage, if the DC voltage at the output terminal of the switched reluctance motor converter itself is too low, it will inevitably increase the subsequent voltage. The boosted pressure even requires several stages of boosting, which increases the system loss.

In the field of small and medium-sized switched reluctance motors, in order to improve the adaptability of the system, it is hoped that the output voltage can be flexibly adjusted according to the needs or changes of the output terminal, that is, the ability to change the power generation voltage, which is also very beneficial. The maximum power output tracking control of the switched reluctance generator system, because according to the switched reluctance generator theory, if the generator speed changes due to the influence of external input power, its motion electromotive force will change. If the generated voltage changes accordingly at this time, so Realizing the balance between the power generation voltage and the motion electromotive force, the winding current waveform is relatively stable during the power generation stage, which not only helps to improve its power generation output capacity, but also helps to reduce the torque ripple of the switched reluctance generator.

Contents of the invention

According to the above background technology, the present invention proposes a small single converter with capacitive self-excitation, strong scalability, modularization, high output voltage, flexible control, variable power generation voltage, and four-quadrant power generation/electric operation. A power switched reluctance motor system and a control method thereof.

Technical scheme of the present invention is:

A switched reluctance motor converter system, comprising a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube tube, fifth switching tube, sixth switching tube, first diode, second diode, third diode, fourth diode, fifth diode, sixth diode, seventh diode, the eighth diode, the ninth diode, the first phase winding, the second phase winding, and the third phase winding, and its technical feature is that the positive pole of the first capacitor and the negative pole of the second capacitor connected, and connected to the anode of the first switch tube, the anode of the third switch tube, and the anode of the fifth switch tube, and the anode of the second capacitor is connected to the cathode of the first diode and the anode of the fourth diode The cathode and the cathode of the seventh diode are connected, and the cathode of the first capacitor is connected to the cathode of the second switch tube, the anode of the third diode, the cathode of the fourth switch tube, and the anode of the sixth diode , the cathode of the sixth switch tube is connected to the anode of the ninth diode, the anode of the first diode is connected to the cathode of the second diode, and the anode of the third capacitor is connected, and the cathode of the first switch tube is connected to the anode of the ninth diode. The anodes of the two diodes, one end of the first phase winding, and the cathode of the third diode are connected, the other end of the first phase winding is connected to the cathode of the third capacitor, and the anode of the second switch tube, and the anode of the fourth diode is connected to the anode of the third diode. The cathode of the fifth diode is connected to the anode of the fourth capacitor, the cathode of the third switch tube is connected to the anode of the fifth diode, one end of the second phase winding, and the cathode of the sixth diode, and the other end of the second phase winding It is connected with the cathode of the fourth capacitor and the anode of the fourth switch tube, the anode of the seventh diode is connected with the cathode of the eighth diode and the anode of the fifth capacitor, the cathode of the fifth switch tube is connected with the anode of the eighth diode, One end of the third phase winding is connected to the cathode of the ninth diode, and the other end of the third phase winding is connected to the negative pole of the fifth capacitor and the anode of the sixth switching tube.

A control method of a switched reluctance motor converter system of the present invention is as follows:

When operating as a switched reluctance generator, according to the operating principle of the switched reluctance generator, when the first phase winding needs to be energized to work, the operation is controlled according to the following three steps:

(1) Control the first switching tube and the second switching tube to be turned on simultaneously, and the energy storage of the first capacitor is used as the excitation power supply to supply and excite the first phase winding, and also charge the third capacitor;

(2) According to the rotor position information of the switched reluctance generator, when the excitation stage of the above step (1) needs to end, it is divided into two working modes a and b:

a. At the end of the excitation phase, the current of the first phase winding detected cannot reach the required value, the first switching tube is turned off, the second switching tube remains on, and it enters the freewheeling phase of the first phase winding. When the winding current reaches the required value before the specified rotor angle position, the second switch tube is turned off, and the freewheeling phase ends, but when the first-phase winding current still cannot reach the required value at the specified maximum rotor angle position, the current is still Turn off the second switching tube, and enter the power generation stage after the freewheeling stage;

b. When the excitation phase needs to end, the detected first-phase winding current has reached the required value, turn off the first switching tube and the second switching tube, and directly enter the power generation phase;

(3) The power generation stage is divided into two working modes c and d:

c. Keep the first switching tube and the second switching tube in the disconnected state, the energy stored in the first phase winding and the third capacitor is output to the first capacitor and the second capacitor via the third diode and the first diode to generate electricity and output;

d. Keep the second switching tube in the disconnected state, turn on the first switching tube, and the energy stored in the first phase winding and the third capacitor will be output to the second capacitor through the first diode and the first switching tube;

When it is necessary to increase the power generation voltage at the output terminal, that is, the voltage at both ends of the first capacitor and the second capacitor series branch, the (3) step, that is, the working mode of the power generation stage, maintains the d mode; otherwise, when the power generation voltage needs to be reduced, maintain the c mode mode; however, when the energy storage of the first capacitor, that is, the voltage at both ends is lower than the set minimum value, the working mode of the power generation stage can only be mode c;

When operating as a switched reluctance motor, according to the operating principle of the switched reluctance motor, when the first phase winding needs to be energized to work, the operation is controlled according to the following two steps:

(1) Simultaneously control the first switch tube and the second switch tube to be turned on and turned on;

(2) When it is necessary to end the phase winding energization according to the rotor position information, disconnect the first switch tube and the second switch tube at the same time;

The above are the operation control steps of the switched reluctance generator and the motor when the first phase winding needs to work. According to the rotor position information, when the second phase winding and the third phase winding need to work, the work control steps are the same as the first phase winding. Specifically, the corresponding relationship between the components used in the converter circuit where the second phase winding and the third phase winding are located and the components used in the above first phase winding is: the third switching tube and the fifth switching tube correspond to the first switching tube, and the fourth switching tube The tube and the sixth switching tube correspond to the second switching tube, the fourth capacitor and the fifth capacitor correspond to the third capacitor, the fourth diode and the seventh diode correspond to the first diode, the fifth diode and the eighth The diode corresponds to the second diode, and the sixth diode and the ninth diode correspond to the third diode.

Technical effect of the present invention mainly contains:

(1) In the converter structure of the present invention, the excitation power comes only from the first capacitor, and self-charging can be realized during the power generation stage, which not only greatly simplifies the structure and reduces hardware and control costs, but also has a high degree of intelligence and reduces labor costs.

(2) The converter structure of the present invention has a set of converter modules for each phase winding, so it has strong scalability and is suitable for switched reluctance motors with various odd and even phases (the least main switch type is only suitable for switched reluctance motors with even phases) motor).

(3) The configuration of the circuits related to the third capacitor, the fourth capacitor, and the fifth capacitor in the converter circuit enhances the flexibility of controlling the power generation voltage at the output end, and assists in realizing the difficult problem in the industry of the power generation voltage control of the power converter; at the same time, in Under certain conditions, the output power generation voltage can be further increased to meet the requirements of subsequent DC loads or grid-connected terminals for a higher value of DC voltage.

(4) During the power generation stage, the switching and duty cycle control of the first switching tube can be flexibly adjusted in response to factors such as different loads and their changes, or changes in input power, and energy storage changes in the first capacitor, which enhances the adaptability of the entire system. Flexibility, reliability, fault ride-through ability, etc.; at the same time, the adjustment of the power generation voltage is beneficial to the maximum power output tracking, reducing torque ripple and other major issues in the switched reluctance motor field.

(5) The same set of converter structure can realize the load control of the switched reluctance motor as an electric motor at the same time, it can be regulated by four-quadrant operation, and it also has the ability to regenerate energy.

Description of drawings

FIG. 1 is a structural diagram of the switched reluctance motor converter system of the present invention.

Detailed ways

The switched reluctance motor in this embodiment has three-phase windings, which are M/N/P three-phase windings according to the order distributed on the stator. Each phase winding is composed of two branch windings and is symmetrically wound on different salient poles of the stator. Above, that is, the six salient poles of the stator, as shown in Figure 1 is the main converter circuit of the three-phase winding switched reluctance motor of this embodiment.

The switched reluctance motor converter system consists of a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a first switch V1, a second switch V2, a third switch The tube V3, the fourth switch tube V4, the fifth switch tube V5, the sixth switch tube V6, the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the Fifth diode D5, sixth diode D6, seventh diode D7, eighth diode D8, ninth diode D9, first phase winding M, second phase winding N, third phase winding Composed of P, the positive pole of the first capacitor C1 is connected to the negative pole of the second capacitor C2, and is connected to the anode of the first switching tube V1, the anode of the third switching tube V3, and the anode of the fifth switching tube V5, and the positive pole of the second capacitor C2 is connected to the first diode The cathode of the tube D1, the cathode of the fourth diode D4, and the cathode of the seventh diode D7 are connected, the cathode of the first capacitor C1 is connected to the cathode of the second switching tube V2, the anode of the third diode D3, the cathode of the fourth switching tube V4, The anode of the six diodes D6, the cathode of the sixth switch tube V6, and the anode of the ninth diode D9 are connected, the anode of the first diode D1 is connected to the cathode of the second diode D2, and the anode of the third capacitor C3, and the first switch tube The cathode of V1 is connected to the anode of the second diode D2, one end of the first phase winding M, and the cathode of the third diode D3, the other end of the first phase winding M is connected to the cathode of the third capacitor C3, and the anode of the second switching tube V2, The anode of the fourth diode D4 is connected to the cathode of the fifth diode D5 and the anode of the fourth capacitor C4, the cathode of the third switching tube V3 is connected to the anode of the fifth diode D5, one end of the second phase winding N, and the sixth diode D6 The cathode is connected, the other end of the second phase winding N is connected to the negative pole of the fourth capacitor C4, the anode of the fourth switching tube V4 is connected, the anode of the seventh diode D7 is connected to the cathode of the eighth diode D8, and the positive pole of the fifth capacitor C5 is connected. The cathode of the switching tube V5 is connected to the anode of the eighth diode D8, one end of the third phase winding P, and the cathode of the ninth diode D9, and the other end of the third phase winding P is connected to the negative pole of the fifth capacitor C5 and the anode of the sixth switching tube V6 .

The control method of the three-phase switched reluctance motor converter system in this embodiment is as follows:

When operating as a switched reluctance generator, according to the operating principle of the switched reluctance generator, when the first phase winding M needs to be energized to work, the operation is controlled according to the following three steps:

(1) Control the first switching tube V1 and the second switching tube V2 to be turned on and on at the same time, and the first capacitor C1 serves as the excitation power supply. The first switching tube V1 and the second switching tube V2 supply power to the first phase winding M for excitation, and also via The second diode D2 charges the third capacitor C3, and the reverse bias of the first diode D1 and the third diode D3 is cut off;

(2) According to the rotor position information of the switched reluctance generator, when the excitation stage of the above step (1) needs to end, it is divided into two working modes a and b, respectively:

a. The current of the first phase winding M detected at the end of the excitation phase cannot reach the required value, the first switching tube V1 is turned off, the second switching tube V2 remains on, and the freewheeling phase of the first phase winding M is entered. That is, the self-closed loop of the first phase winding M-the second switching tube V2-the third diode D3, since the voltage at both ends of the first phase winding M is zero at this time, the winding current will rise rapidly. When the M current reaches the required value before the specified rotor angle position, the second switch tube V2 is turned off, and the freewheeling phase ends; but when the M current of the first phase winding still cannot reach the required value at the maximum position of the specified rotor angle , still turn off the second switching tube V2, and enter the power generation stage after the freewheeling stage;

b. When the excitation phase needs to end, the detected current of the first phase winding M has reached the required value, the first switching tube V1 and the second switching tube V2 are turned off, and the power generation phase is directly entered, and there is no a working mode;

(3) The power generation stage is divided into two working modes c and d:

c. Keep the first switching tube V1 and the second switching tube V2 in the disconnected state, and the energy stored in the first phase winding M and the third capacitor C3 generates electricity and outputs to the first phase through the third diode D3 and the first diode D1. The capacitor C1 and the second capacitor C2 are output together, the second diode is reverse biased and cut off, the output voltage is the sum of the voltage across the first capacitor C1 plus the voltage across the second capacitor C2 is equal to the voltage across the first phase winding M plus the second The sum of the voltages across the three capacitors C3;

d. Keep the second switch tube V2 in the off state, turn on the first switch tube V1, and the energy stored in the first phase winding M and the third capacitor C3 will be output to the power supply through the first diode D1 and the first switch tube V1 The second capacitor C2 is connected to the output, and the second diode is reverse-biased and cut off. At this time, the sum of the voltage across the two ends of the first phase winding M plus the voltage across the third capacitor C3 is equal to the voltage across the second capacitor C2. Relatively speaking, this The output power generation voltage obtained in mode c is greater than the output voltage in mode c;

When it is necessary to increase the power generation voltage at the output terminal, that is, the voltage at both ends of the series branch of the first capacitor C1 and the second capacitor C2, the operation mode of the step (3), that is, the power generation stage, remains in the d mode; otherwise, when the power generation voltage needs to be reduced, Keep the c mode, so that the regulation of the power generation voltage can be realized by adjusting the duty cycle of the first switching tube V1 in the power generation stage; however, when the energy storage of the first capacitor C1, that is, the voltage at both ends is lower than the set At the minimum value, the working mode of the power generation stage can only be c mode, because the first capacitor C1 cannot be too low as the excitation power supply. In addition, when necessary, when a larger excitation voltage is required (the need for enhanced excitation), it is often maintained at c The power generation stage under the mode; Also, according to the switched reluctance generator theory, if the generator speed changes, the motion electromotive force of the first phase winding M changes, in order to maintain the balance of the generated voltage and the motion electromotive force to promote the stability of the phase winding current and lower torque ripple and larger output electric energy, it is also necessary to timely adjust the working ratio of the c/d two modes; in short, the converter structure and control mode of this embodiment can fully meet the various needs of the system .

When operating as a switched reluctance motor, according to the operating principle of the switched reluctance motor, when the first phase winding M needs to be energized to work, the operation is controlled according to the following two steps:

(1) Simultaneously control the first switch tube V1 and the second switch tube V2 to be turned on and on, and the first diode D1 and the third diode D3 are reverse-biased and cut off. Although the third capacitor C3 passes through the second diode D2 is charged, but also due to the effect of the second diode D2, it will not resonate with the first phase winding M;

(2) When it is necessary to end the energization of the first phase winding M according to the rotor position information, the first switching tube V1 and the second switching tube V2 are disconnected at the same time, and the energy stored in the first phase winding M passes through the first diode D1 and the second switching tube V2. The three diodes D3 are fed back to power regeneration, and the third capacitor C3 is fed back in series with it to realize the regeneration of energy storage;

In the electric operation of this embodiment, if it is long-term electric operation, both ends of the first capacitor C1 are connected in parallel to a storage battery or other DC power supply for protection.

The above is the operation control steps of the switched reluctance generator and the motor when the first phase winding M needs to work. According to the rotor position information, when the second phase winding N and the third phase winding P need to work, the work control steps are the same as those of the first phase The winding M is the same, and the corresponding relationship between the components used in the converter circuit where the second phase winding N and the third phase winding P are located and the above components used in the first phase winding M is as follows: the third switching tube V3 and the fifth switching tube V5 Corresponding to the first switching tube V1, the fourth switching tube V4 and the sixth switching tube V6 corresponding to the second switching tube V2, the fourth capacitor C4 and the fifth capacitor C5 corresponding to the third capacitor C3, the fourth diode D4 and the seventh and second Diode D7 corresponds to the first diode D1, the fifth diode D5 and the eighth diode D8 correspond to the second diode D2, the sixth diode D6 and the ninth diode D9 correspond to the third diode Tube D3.

It can be seen from the structure and embodiments of the present invention that when the switched reluctance motor has a non-three-phase winding structure, its converter circuit only faces the problem of increasing or decreasing the corresponding phase winding conversion branches. The modular structure theoretically Compatible with all phases of switched reluctance motors, and four-quadrant operation for generating/motoring.

Claims (2)

1. a kind of switched reluctance machines converter system, by the first capacitor, the second capacitor, third capacitor, the 4th capacitance Device, the 5th capacitor, first switch pipe, second switch pipe, third switching tube, the 4th switching tube, the 5th switching tube, the 6th switch Pipe, the first diode, the second diode, third diode, the 4th diode, the 5th diode, the 6th diode, the seven or two pole Pipe, the 8th diode, the 9th diode, the first phase winding, the second phase winding, third phase winding composition, technical characteristic is institute It states the first capacitor anode to connect with second capacitor anode, and is switched with the first switch tube anode, the third Tube anode, the 5th switch tube anode connection, the second capacitor anode and first diode cathode, the four or two pole Tube cathode, the 7th diode cathode connection, the first capacitor anode and the second switch tube cathode, the three or two pole Tube anode, the 4th switch tube cathode, the 6th diode anode, the 6th switch tube cathode, the 9th 2 pole Tube anode connects, and the first diode anode is connect with second diode cathode, the third capacitor anode, first switch Tube cathode is connect with the second diode anode, first phase winding one end, third diode cathode, the first phase winding other end It is connect with third capacitor anode, second switch tube anode, the 4th diode anode and the 5th diode cathode, described the Four capacitor anodes connect, and third switchs tube cathode and the 5th diode anode, second phase winding one end, the 6th diode Cathode connects, and the second phase winding other end and the 4th capacitor anode, the 4th switch tube anode are connect, the 7th diode anode and 8th diode cathode, the 5th capacitor anode connection, it is the 5th switch tube cathode and the 8th diode anode, described Third phase winding one end, the connection of the 9th diode cathode, the third phase winding other end and the 5th capacitor anode, the 6th switching tube Anode connects.

2. a kind of control method of switched reluctance machines converter system according to claim 1 is：

When being run as switch reluctance generator, according to switch reluctance generator operation logic, when the first phase winding needs to be powered When work, controls and run by following three step：

(1) first switch pipe and second switch pipe are controlled and is closed at conducting, the energy storage of the first capacitor as field power supply to First phase winding also charges to third capacitor for electrical excitation；

(2) it is divided into as a, b two at the end of above (1) step excitation stage needs according to switch reluctance generator rotor position information Kind operating mode：

A. the first phase winding electric current detected at the end of excitation stage need cannot reach desirable value, turn off first switch pipe, the Two switching tubes are held on, and into the freewheeling period of the first phase winding, wait for the first phase winding electric current in defined rotor angle position When reaching desirable value before setting, second switch pipe is turned off, freewheeling period terminates, but in defined rotor angle maximum position first When phase winding electric current cannot still reach desirable value, still off second switch pipe enters power generating stage after terminating freewheeling period；

B. the first phase winding electric current detected at the end of excitation stage need has reached desirable value, turns off first switch pipe and second Switching tube is directly entered power generating stage；

(3) power generating stage is divided into two kinds of operating modes of c, d：

C. first switch pipe and second switch pipe off-state are kept, the energy storage of the first phase winding and third capacitor is via third Diode, the power generation output of the first diode to the first capacitor and the second capacitor and export；

D. second switch pipe off-state is kept, conducting first switch pipe, the energy storage of the first phase winding and third capacitor are closed It to the second capacitor and is exported via the first diode, the power generation output of first switch pipe；

When needing to increase the both end voltage of i.e. the first capacitor of output end generating voltage and the second capacitor series arm, the (3) operating mode of step, that is, power generating stage keeps d patterns；Otherwise when needing to reduce generating voltage, c patterns are kept；But When minimum value of the energy storage, that is, both end voltage of the first capacitor less than setting, power generating stage operating mode is only c patterns；

When being run as switched reluctance motor, according to switched reluctance motor operation logic, when the first phase winding needs to be powered When work, controls and run by following two step：

(1) while first switch pipe and the closure conducting of second switch pipe being controlled；

(2) when need to terminate phase winding energization according to rotor position information, first switch pipe and second switch pipe are simultaneously switched off；

Switch reluctance generator when work and electric motor operation rate-determining steps are needed for the first phase winding above, according to rotor-position Information, when the second phase winding, third phase winding need work, job control step is identical as the first phase winding, specific second phase The correspondence of each component and component used in the first phase winding as above used in convertor circuit where winding and third phase winding For：Third switching tube and the 5th switching tube correspond to first switch pipe, and the 4th switching tube and the 6th switching tube correspond to second switch pipe, 4th capacitor and the 5th capacitor correspond to third capacitor, and the 4th diode and the 7th diode pair answer the first diode, the Five diodes and the 8th diode pair answer the second diode, the 6th diode and the 9th diode pair to answer third diode.