Wind-solar complementary power generation power converter with variable excitation switch reluctance wind power generator

Abstract

This wind-solar hybrid power converter, incorporating a variable-excitation switched reluctance wind turbine, consists of nine switching transistors, three-phase windings, five diodes, seven capacitors, four inductors, and a photovoltaic cell. The four inductors are coupled in pairs, serving in the coupled power generation of the switched reluctance generator and the photovoltaic cell, as well as in the variable excitation circuit. During the excitation and power generation of the switched reluctance generator, the conversion and output of the photovoltaic cell are integrated, and the output voltage can be directly boosted. To meet the needs of high-speed wind power, variable excitation can be achieved through a buck-boost unit and a switched capacitor unit, enriching the control methods. The entire power converter considers simultaneous wind and solar power generation and supply, separate power generation and supply, and complementary modes, offering high flexibility, high reliability, high utilization, and a common ground without isolation. It is suitable for applications in low-power, high-speed switched reluctance wind turbines and photovoltaic hybrid power generation and power conversion.

Description

Technical Field

[0001] This invention relates to the field of wind-solar hybrid power generation, specifically to a novel power converter and its control method that couples and complements a variable excitation switched reluctance wind turbine power converter and a photovoltaic power converter. Background Technology

[0002] Wind-solar hybrid power generation is a more efficient way to utilize clean energy power generation that has received widespread attention in recent years. However, the two often use their own converters to generate and initially convert the power. For example, the AC power generated by the wind turbine needs to be rectified first, and the power from each of the photovoltaic cells is combined and converted to a suitable voltage.

[0003] Switched reluctance generators can directly generate direct current, thus eliminating the need for a rectifier stage when used as wind turbines. In many wind-solar hybrid applications, high investment costs and low operating costs are often required; therefore, wind-solar hybrid power generation devices with simple structures, easy control, and high reliability certainly have a promising future.

[0004] Switched reluctance generator power converters have received some attention from the industry in recent years and have achieved certain development. Some research results have also been obtained on MPPT control under variable speed wind power conditions, which has provided the possibility of introducing wind-solar hybrid power generation systems.

[0005] In other words, designing a novel switched reluctance generator power converter that includes a photovoltaic power generation access port to couple and convert wind and solar power generation has become a practically significant challenge. Summary of the Invention

[0006] Based on the above background technology, the present invention proposes a novel power converter and its control method, which couples a novel variable excitation switched reluctance wind turbine power converter into a photovoltaic power generation port. The switched reluctance generator generates electricity while the photovoltaic cell complementarily couples to generate electricity output. The structure is simple and practical, and it is suitable for application in the field of small high-speed wind power generation and photovoltaic power generation complementary power supply system.

[0007] The technical solution of this invention is as follows:

[0008] A wind-solar hybrid power converter with a variable-excitation switched reluctance wind turbine consists of a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, a ninth switch, a first phase winding, a second phase winding, a third phase winding, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, a first inductor, a second inductor, a third inductor, a fourth inductor, and photovoltaic cells. The anode of the first switching transistor is connected to the anodes of the second and third switching transistors and one end of the third inductor, serving as the positive terminal of the excitation power input for the switched reluctance generator. The cathode of the first switching transistor is connected to one end of the first phase winding, the cathode of the second switching transistor is connected to one end of the second phase winding, and the cathode of the third switching transistor is connected to one end of the third phase winding. The other end of the first phase winding is connected to the other end of the second and third phase windings, the anode of the fourth switching transistor, the cathode of the first diode, and one end of the first capacitor. The other end of the first capacitor is connected to the cathode of the fifth switching transistor, the anode of the second diode, the anode of the third diode, and the first inductor. One end of the inductor is connected to the cathode of the third diode, the anode of the fourth diode, one end of the third capacitor, one end of the fourth capacitor, and one end of the second inductor. The other end of the second inductor is connected to one end of the second capacitor. The other end of the second capacitor is connected to the cathode of the fourth diode and the anode of the fifth diode. The cathode of the fifth diode is connected to the other end of the third capacitor and serves as the positive output terminal of the power converter. The anode of the fifth switch is connected to the cathode of the second diode and the positive terminal of the photovoltaic cell. The negative terminal of the photovoltaic cell is connected to the cathode of the fourth switch, the anode of the first diode, the other end of the first inductor, the other end of the fourth capacitor, the cathode of the sixth switch, and one end of the fifth capacitor and serves as the negative output terminal of the power converter and the negative input terminal of the excitation power supply. The anode of the ninth switch is connected to one end of the seventh capacitor and is connected to the positive output terminal of the power converter. The cathode of the ninth switch is connected to the anode of the eighth switch and one end of the sixth capacitor. The cathode of the eighth switch is connected to the other end of the seventh capacitor, the anode of the seventh switch, and the other end of the fifth capacitor. The other end of the sixth capacitor is connected to one end of the fourth inductor. The other end of the fourth inductor is connected to the anode of the sixth switch, the cathode of the seventh switch, and the other end of the third inductor. The first inductor is coupled to the second inductor, and the third inductor is coupled to the fourth inductor.

[0009] The control method of the wind-solar hybrid power converter with variable-excitation switched reluctance wind turbine is divided into three power generation and conversion modes according to the load requirements at the output end of the power converter and the availability of wind and solar resources. The first mode is in which both the switched reluctance generator and the photovoltaic cell generate and output electrical energy. The corresponding power converter control and operation process is as follows:

[0010] The photovoltaic cells provide electrical energy through the regulation of the fifth switching transistor. When the switched reluctance generator operates under wind power, a buck-boost chopper unit composed of the sixth and seventh switching transistors, the fifth capacitor, and the third inductor, together with a switched capacitor unit composed of the eighth and ninth switching transistors, the sixth and seventh capacitors, and the fourth inductor, forms a variable excitation circuit. This circuit provides excitation power to meet the different excitation voltage requirements resulting from changes in the switched reluctance generator's rotational speed due to wind speed variations. Given this excitation power supply, the power converter operates as follows: based on the rotor position information of the switched reluctance generator... When the first phase winding needs to be put into operation, the first and fourth switching transistors are closed, and the excitation power supply energizes the first phase winding. This is the excitation stage. During this stage, the fifth switching transistor remains off. The energy stored in the first capacitor is transferred to the first inductor through the fourth switching transistor to charge it. Consequently, the second inductor coupled to it discharges, and together with the second capacitor, it charges the third capacitor via the fifth diode and outputs electrical energy, including the fourth capacitor. When the excitation stage needs to end according to the rotor position information of the switched reluctance generator, the fourth switching transistor is disconnected, and the generator enters the power generation stage. The excitation power supply, together with the first phase winding, is transferred to the first switching transistor to charge it. A switching transistor charges the first capacitor. Simultaneously, before the freewheeling current of the first inductor is complete, the first inductor charges and outputs to the fourth capacitor via the third diode. The second inductor and the second capacitor, together, charge and output to the third capacitor via the fifth diode. Before the freewheeling current of the first inductor is complete and the fifth switching transistor is turned on, the excitation power supply and the first phase winding, in addition to charging the first capacitor, simultaneously charge the first inductor. Thus, the coupled second inductor charges the second capacitor in the reverse direction via the fourth diode. The output terminal relies on the third and fourth capacitors to maintain output power. Then, after the fifth switching transistor is turned on, the power from the photovoltaic cell is transmitted through the fifth switching transistor and the first phase winding. The three diodes charge the fourth capacitor and output the power. When the first phase winding's power generation phase needs to end according to the rotor position information of the switched reluctance generator, the first and fifth switching transistors are disconnected, and the first phase winding's operation ends. If the next phase winding has not yet started working, the residual magnetism of the first inductor continues to the first capacitor through the first diode. According to the rotor position information of the switched reluctance generator, when the second phase winding needs to start working, the difference between the working process and that of the first phase winding is that the second switching transistor is used instead of the first switching transistor. When the third phase winding needs to start working, the difference between the working process and that of the first phase winding is that the third switching transistor is used instead of the first switching transistor.

[0011] The second mode is for photovoltaic cells to output power independently. The power converter regulation and operation process is as follows: the first, second, third, fourth, sixth, seventh, eighth, and ninth switches are always kept off. There are two states: the fifth switch is on and off. When the fifth switch is on, the photovoltaic cells charge the fourth capacitor through the fifth switch and the third diode and output power. At the same time, when charging the first inductor, the charging is switched to the second inductor charging the second capacitor through the fourth diode. After the fifth switch is off, the second capacitor charges the third capacitor through the fifth diode and output power.

[0012] The third mode is where the switched reluctance generator generates electricity independently, and the fifth switch is always kept off. The other switches of the power converter are controlled in the same way as in the first mode. The difference in the working process is that since the photovoltaic cell has no output, i.e. the fifth switch is always off, there is no process of the photovoltaic cell charging the fourth capacitor and outputting electricity.

[0013] When the switched reluctance generator is operating, the buck-boost chopper unit, composed of the sixth switch, the seventh switch, the fifth capacitor, and the third inductor, together with the switched capacitor unit, composed of the eighth switch, the ninth switch, the sixth capacitor, the seventh capacitor, and the fourth inductor, forms a variable excitation circuit. The control method is as follows: the switching frequencies of the sixth, seventh, eighth, and ninth switches are the same; the sixth and seventh switches are complementary in conduction; the eighth and ninth switches are complementary in conduction; the duty cycles of the sixth and eighth switches are the same; the duty cycles of the seventh and ninth switches are the same; and the turn-on time of the eighth switch leads that of the sixth switch. Different output excitation voltages are obtained by adjusting the duty cycles.

[0014] The main technical effects of this invention are:

[0015] This invention further enriches and develops the technology in the field of wind-solar hybridization. In addition to introducing a switched reluctance generator as a wind turbine, it also brings about a series of technological developments related to power converters. In particular, it directly couples the power conversion process of the wind turbine generator and the conversion process of the photovoltaic cell together inside the power converter, reducing costs, size and weight, while directly increasing the high voltage output. In addition, the power converter of this invention does not have an isolation stage, including the variable excitation circuit, and achieves common ground.

[0016] The power converter of this invention has three operating modes, which take into account the different resource deficiencies of wind and solar power, and ensure the reliability of wind and solar complementarity. At the same time, since the switched reluctance generator directly generates DC power, which is the same as the DC power directly output by the photovoltaic cell, the power converter of this invention has an extremely simple structure and the control is not complicated.

[0017] When the switched reluctance generator is working, it uses power converter output energy feedback to provide variable excitation power, which meets the needs of variable speed wind power performance improvement, especially maximum power point tracking (MPPT) control. Attached Figure Description

[0018] Figure 1 The diagram shown is a circuit structure diagram of the wind-solar hybrid power converter for a wind turbine generator with variable excitation switching reluctance according to the present invention. Detailed Implementation

[0019] The circuit structure of the wind-solar hybrid power converter with variable excitation switched reluctance wind turbine in this embodiment is shown in the attached figure. Figure 1As shown, it consists of a first switch V1, a second switch V2, a third switch V3, a fourth switch V4, a fifth switch V5, a sixth switch V6, a seventh switch V7, an eighth switch V8, a ninth switch V9, a first phase winding M, a second phase winding N, a third phase winding P, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, a first inductor L1, a second inductor L2, a third inductor L3, a fourth inductor L4, and a photovoltaic cell PV. The anode of transistor V1 is connected to the anodes of the second switch transistor V2 and the third switch transistor V3, as well as one end of the third inductor L3, and serves as the positive terminal of the excitation power input for the switched reluctance generator. The cathode of the first switch transistor V1 is connected to one end of the first phase winding M, the cathode of the second switch transistor V2 is connected to one end of the second phase winding N, and the cathode of the third switch transistor V3 is connected to one end of the third phase winding P. The other end of the first phase winding M is connected to the other end of the second phase winding N, the other end of the third phase winding P, the anode of the fourth switch transistor V4, the cathode of the first diode D1, and one end of the first capacitor C1. The other end of the first capacitor C1 is connected to the cathode of the fifth switch transistor V5, the anode of the second diode D2, the anode of the third diode D3, and one end of the first inductor L1. The cathode of diode D3 is connected to the anode of fourth diode D4, one end of third capacitor C3, one end of fourth capacitor C4, and one end of second inductor L2. The other end of second inductor L2 is connected to one end of second capacitor C2. The other end of second capacitor C2 is connected to the cathode of fourth diode D4 and the anode of fifth diode D5. The cathode of fifth diode D5 is connected to the other end of third capacitor C3 and serves as the positive output terminal of the power converter. The anode of fifth switch V5 is connected to the cathode of second diode D2 and the positive terminal of photovoltaic cell PV. The negative terminal of photovoltaic cell PV is connected to the cathode of fourth switch V4, the anode of first diode D1, the other end of first inductor L1, the other end of fourth capacitor C4, the cathode of sixth switch V6, and the fifth capacitor. One end of C5 serves as the negative terminal of the power converter output and the negative terminal of the excitation power input. The anode of the ninth switch V9 is connected to one end of the seventh capacitor C7 and to the positive terminal of the power converter output. The cathode of the ninth switch V9 is connected to the anode of the eighth switch V8 and one end of the sixth capacitor C6. The cathode of the eighth switch V8 is connected to the other end of the seventh capacitor C7, the anode of the seventh switch V7, and the other end of the fifth capacitor C5. The other end of the sixth capacitor C6 is connected to one end of the fourth inductor L4. The other end of the fourth inductor L4 is connected to the anode of the sixth switch V6, the cathode of the seventh switch V7, and the other end of the third inductor L3. The first inductor L1 is coupled to the second inductor L2, and the third inductor L3 is coupled to the fourth inductor L4.

[0020] The output voltage of the power converter is the generator voltage, which is the sum of the voltages of the third capacitor C3 and the fourth capacitor C4; the input voltage of the excitation power supply is the excitation voltage.

[0021] All switching transistors are three-terminal fully controlled power electronic switching devices; all capacitors must be large enough; the first phase winding M, the second phase winding N, and the third phase winding P are the three-phase windings of the wind-driven switched reluctance generator; the overlap factor of the switched reluctance generator is not greater than zero; the photovoltaic cell PV is the power output of the photovoltaic power generation system.

[0022] The control method of the wind-solar hybrid power converter with variable-excitation switched reluctance wind turbine in this embodiment is divided into three energy generation and conversion modes according to the load requirements at the output end of the power converter and the wind and solar energy resources. The first mode is that both the switched reluctance generator and the photovoltaic cell (PV) generate and output electrical energy. The corresponding power converter control and operation process is as follows:

[0023] The photovoltaic (PV) cells generate electricity, which is output through the regulation of the fifth switch, V5. When the switched reluctance generator (SRG) operates under wind power, a buck-boost chopper unit composed of the sixth switch, V6, the seventh switch, V7, the fifth capacitor, C5, and the third inductor, along with a switched capacitor unit composed of the eighth switch, V8, the ninth switch, V9, the sixth capacitor, C6, the seventh capacitor, C7, and the fourth inductor, L4, forms a variable excitation circuit. This circuit provides different excitation voltage requirements based on the varying wind speed and the resulting changes in the SRG's rotational speed. The goal is to achieve the optimal power output of the SRG, provided the excitation power supply is adequate. The operation of each phase winding of the switched reluctance generator and the photovoltaic cells, i.e., the entire power converter, is as follows: Based on the rotor position information of the switched reluctance generator, when the first phase winding M needs to be put into operation, the first switch V1 and the fourth switch V4 are closed and turned on. The excitation energy from the third inductor L3 excites the first phase winding M. This is the excitation stage. During this stage, the fifth switch V5 will remain off. The energy stored in the first capacitor C1 will be transferred to the first inductor L1 through the fourth switch V4 to charge it. As a result, the second inductor L2 coupled with it discharges and, together with the second capacitor C2, charges the third capacitor C3 through the fifth diode D5 and outputs electrical energy, including the fourth capacitor C4. When the excitation phase of the switched reluctance generator (SRG) needs to end according to the rotor position information, the fourth switch V4 is disconnected, and the generator enters the power generation phase. The excitation power supply, together with the first phase winding M, charges the first capacitor C1 via the first switch V1. Simultaneously, before the freewheeling current of the first inductor L1 is completed, the first inductor L1 charges and outputs power to the fourth capacitor C4 via the third diode D3. The second inductor L2, together with the second capacitor C2, charges and outputs power to the third capacitor C3 via the fifth diode D5. Before the freewheeling current of the first inductor L1 is completed and the fifth switch V5 is not turned on, the excitation power supply and the first phase winding M, in addition to charging the first capacitor C1, simultaneously charge and output power to the fourth capacitor C4. When inductor L1 is charged, the coupled second inductor L2 is charged in reverse through the fourth diode D4 to the second capacitor C2. The output terminal relies on the third capacitor C3 and the fourth capacitor C4 to maintain the output power. Then, after the fifth switch V5 is turned on, the power of the photovoltaic cell PV is charged to the fourth capacitor C4 through the fifth switch V5 and the third diode D3 and output. According to the rotor position information of the switched reluctance generator, when the power generation stage of the first phase winding M needs to end, the first switch V1 and the fifth switch V5 are disconnected, and the first phase winding M ends its work. At this time, if the next phase winding has not yet started working, the residual magnetism of the first inductor L1 is freewheeled to the first capacitor C1 through the first diode D1.Based on the rotor position information of the switched reluctance generator, when the second phase winding N needs to be engaged, the difference between its operation and that of the first phase winding M is simply replacing the first switching transistor V1 with the second switching transistor V2. Similarly, when the third phase winding P needs to be engaged, the difference is simply replacing the first switching transistor V1 with the third switching transistor V3. The second diode D2 is used so that when the photovoltaic cell PV energy approaches its lower limit and the voltage is too low (below the voltage at the fourth capacitor C4), the freewheeling current of the first inductor L1 will not pass through the third diode D3 but through the second diode D2 to maintain the photovoltaic cell PV voltage. This ensures that the voltage is maintained when the photovoltaic cell PV cannot generate power at full load, facilitating the possible feedback of photovoltaic power generation, including the need for starting power before restarting the photovoltaic cell PV after it has stopped generating power.

[0024] As can be seen from the first mode control and working process above, the output voltage of the power converter is higher than the excitation voltage and the photovoltaic cell PV voltage. Considering that the ratio of the number of coupling turns of the first inductor L1 and the second inductor L2 can be adjusted, a larger output voltage can be obtained, thus making it easier to directly increase the voltage output.

[0025] The second mode involves independent power output from the photovoltaic (PV) cells. For example, if insufficient wind resources prevent the switched reluctance wind turbine from operating and generating electricity, the corresponding power converter regulation process is as follows: the first switch V1, the second switch V2, the third switch V3, the fourth switch V4, the sixth switch V6, the seventh switch V7, the eighth switch V8, and the ninth switch V9 are always kept off. There are two states: the fifth switch V5 is on and off. When the fifth switch V5 is on, the PV cells generate electricity through the fifth switch V5 and the third diode. D3 charges and outputs to the fourth capacitor C4. Simultaneously, while charging the first inductor L1, the second inductor L2 charges the second capacitor C2 via the fourth diode D4. After the fifth switch V5 is turned off, the second capacitor C2 charges and outputs to the third capacitor C3 via the fifth diode D5. It should be noted that in this mode, since the switching of the fifth switch V5 is no longer constrained by the operation of each phase winding of the switched reluctance generator in the first mode, the duty cycle and switching frequency of the fifth switch V5 can be adjusted according to the power quality and load requirements at the output terminal.

[0026] The third mode is when the switched reluctance generator generates electricity independently. For example, if the solar energy resources are insufficient and the photovoltaic cell PV cannot output power, the fifth switch V5 will always remain in the off state. The other switches of the power converter are controlled in the same way as in the first mode. The difference in the working process is that since the photovoltaic cell PV has no output, i.e. the fifth switch V5 is always in the off state, there is no link for the photovoltaic cell PV to charge the fourth capacitor C4 and output power.

[0027] When the switched reluctance generator is operating, the buck-boost chopper unit, composed of the sixth switch V6, the seventh switch V7, the fifth capacitor C5, and the third inductor L3, together with the switched capacitor unit, composed of the eighth switch V8, the ninth switch V9, the sixth capacitor C6, the seventh capacitor C7, and the fourth inductor L4, forms a variable excitation circuit. The control method is as follows: the switching frequencies of the sixth switch V6, the seventh switch V7, the eighth switch V8, and the ninth switch V9 are all the same, all at a high frequency of 10kHz or higher. The sixth switch V6... Switch V6 is complementary to switch V7, and switches V8 and V9 are complementary to switch V9. Switch V6 and V8 have the same duty cycle, and switches V7 and V9 have the same duty cycle. Switch V8 turns on before switch V6 by less than 60 degrees. Different output excitation voltages are obtained by adjusting the duty cycle. The turns ratio between the coupling inductors, i.e., the third inductor L3 and the fourth inductor L4, is set at a certain reasonable ratio to ensure that the adjustable range of the excitation voltage output from the third inductor L3 side meets the requirements of the switched reluctance generator.

Claims

1. A wind-solar hybrid power converter with a variable-excitation switched reluctance wind turbine, comprising a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, a ninth switch, a first phase winding, a second phase winding, a third phase winding, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, a first inductor, a second inductor, a third inductor, a fourth inductor, and photovoltaic cells, characterized in that the first switch... The anode is connected to the anodes of the second and third switching transistors and one end of the third inductor, serving as the positive input terminal of the switched reluctance generator's excitation power supply. The cathode of the first switching transistor is connected to one end of the first phase winding, the cathode of the second switching transistor is connected to one end of the second phase winding, and the cathode of the third switching transistor is connected to one end of the third phase winding. The other end of the first phase winding is connected to the other end of the second and third phase windings, the anode of the fourth switching transistor, the cathode of the first diode, and one end of the first capacitor. The other end of the first capacitor is connected to the cathode of the fifth switching transistor, the anode of the second diode, the anode of the third diode, and the... One end of the first inductor is connected to the cathode of the third diode, one end of the third capacitor, one end of the fourth capacitor, and one end of the second inductor. The other end of the second inductor is connected to one end of the second capacitor. The other end of the second capacitor is connected to the cathode of the fourth diode and the anode of the fifth diode. The cathode of the fifth diode is connected to the other end of the third capacitor and serves as the positive terminal of the power converter output. The anode of the fifth switch is connected to the cathode of the second diode and the positive terminal of the photovoltaic cell. The negative terminal of the photovoltaic cell is connected to the cathode of the fourth switch, the anode of the first diode, the other end of the first inductor, the other end of the fourth capacitor, the cathode of the sixth switch, and... One end of the fifth capacitor serves as the negative terminal of the power converter output and the negative terminal of the excitation power input. The anode of the ninth switch is connected to one end of the seventh capacitor and to the positive terminal of the power converter output. The cathode of the ninth switch is connected to the anode of the eighth switch and one end of the sixth capacitor. The cathode of the eighth switch is connected to the other end of the seventh capacitor, the anode of the seventh switch, and the other end of the fifth capacitor. The other end of the sixth capacitor is connected to one end of the fourth inductor. The other end of the fourth inductor is connected to the anode of the sixth switch, the cathode of the seventh switch, and the other end of the third inductor. The first inductor is coupled to the second inductor, and the third inductor is coupled to the fourth inductor.

2. The control method for the wind-solar hybrid power converter containing a variable-excitation switched reluctance wind turbine as described in claim 1, characterized in that: Based on the load requirements at the output end of the power converter and the availability of wind and solar resources, three power generation and conversion modes are defined. The first mode involves both the switched reluctance generator and the photovoltaic cells generating and outputting electrical energy. The corresponding power converter control and operation process is as follows: The photovoltaic cells provide electrical energy through the regulation of the fifth switching transistor. When the switched reluctance generator operates under wind power, a buck-boost chopper unit composed of the sixth and seventh switching transistors, the fifth capacitor, and the third inductor, together with a switched capacitor unit composed of the eighth and ninth switching transistors, the sixth and seventh capacitors, and the fourth inductor, forms a variable excitation circuit. This circuit provides excitation power to meet the different excitation voltage requirements resulting from changes in the switched reluctance generator's rotational speed due to wind speed variations. Given this excitation power supply, the power converter operates as follows: based on the rotor position information of the switched reluctance generator... When the first phase winding needs to be put into operation, the first and fourth switching transistors are closed, and the excitation power supply energizes the first phase winding. This is the excitation stage. During this stage, the fifth switching transistor remains off. The energy stored in the first capacitor is transferred to the first inductor through the fourth switching transistor to charge it. Consequently, the second inductor coupled to it discharges, and together with the second capacitor, it charges the third capacitor via the fifth diode and outputs electrical energy, including the fourth capacitor. When the excitation stage needs to end according to the rotor position information of the switched reluctance generator, the fourth switching transistor is disconnected, and the generator enters the power generation stage. The excitation power supply, together with the first phase winding, is transferred to the first switching transistor to charge it. A switching transistor charges the first capacitor. Simultaneously, before the freewheeling current of the first inductor is complete, the first inductor charges and outputs to the fourth capacitor via the third diode. The second inductor and the second capacitor, together, charge and output to the third capacitor via the fifth diode. Before the freewheeling current of the first inductor is complete and the fifth switching transistor is turned on, the excitation power supply and the first phase winding, in addition to charging the first capacitor, simultaneously charge the first inductor. Thus, the coupled second inductor charges the second capacitor in the reverse direction via the fourth diode. The output terminal relies on the third and fourth capacitors to maintain output power. Then, after the fifth switching transistor is turned on, the power from the photovoltaic cell is transmitted through the fifth switching transistor and the first phase winding. The three diodes charge the fourth capacitor and output the power. When the first phase winding's power generation phase needs to end according to the rotor position information of the switched reluctance generator, the first and fifth switching transistors are disconnected, and the first phase winding's operation ends. If the next phase winding has not yet started working, the residual magnetism of the first inductor will continue to the first capacitor through the first diode. According to the rotor position information of the switched reluctance generator, when the second phase winding needs to start working, the difference between the working process and that of the first phase winding is that the second switching transistor is used instead of the first switching transistor. When the third phase winding needs to start working, the difference between the working process and that of the first phase winding is that the third switching transistor is used instead of the first switching transistor. The second mode is for photovoltaic cells to output power independently. The power converter regulation and operation process is as follows: the first, second, third, fourth, sixth, seventh, eighth and ninth switches are always kept off. There are two states: the fifth switch is on and off. When the fifth switch is on, the photovoltaic cells charge the fourth capacitor through the fifth switch and the third diode and output power. At the same time, when charging the first inductor, the charging is switched to the second inductor charging the second capacitor through the fourth diode. After the fifth switch is off, the second capacitor charges the third capacitor through the fifth diode and outputs power. The third mode is that the switched reluctance generator generates electricity independently, and the fifth switch is always kept in the off state. The other switches of the power converter are controlled in the same way as the first mode. The difference in the working process is that since the photovoltaic cell has no output, the fifth switch is always in the off state, and there is no link for the photovoltaic cell to charge the fourth capacitor and output. When the switched reluctance generator is operating, the buck-boost chopper unit, composed of the sixth switch, the seventh switch, the fifth capacitor, and the third inductor, together with the switched capacitor unit, composed of the eighth switch, the ninth switch, the sixth capacitor, the seventh capacitor, and the fourth inductor, forms a variable excitation circuit. The control method is as follows: the switching frequencies of the sixth, seventh, eighth, and ninth switches are the same; the sixth and seventh switches are complementary in conduction; the eighth and ninth switches are complementary in conduction; the duty cycles of the sixth and eighth switches are the same; the duty cycles of the seventh and ninth switches are the same; and the turn-on time of the eighth switch leads that of the sixth switch. Different output excitation voltages are obtained by adjusting the duty cycles.

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