A three-phase full-bridge current-source inverter

Abstract

The application discloses a kind of three-phase full-bridge current source type inverter, belong to current source type inverter technical field, comprising: constant current source, inductance, multiple power switch tubes, capacitor and three-phase motor;Wherein, the constant current source is connected in series with the inductance;Multiple power switch tubes are connected to output alternating current to drive motor;Each the power switch tube is used to ensure the unidirectional flow of bridge arm current;Each phase winding in the three-phase motor is provided with two power bridge arms, and the first power bridge arm and the second power bridge arm of each phase winding each include two power switch tubes;The bridge arm midpoint of two power bridge arms is connected with the two ends of the phase winding;Each phase winding end is connected with one capacitor in parallel.The application is improved on the basis of conventional three-phase bridge type current source inverter, each phase winding is provided with two power bridge arms, and each power bridge arm is provided with two power switch tubes, which can significantly improve current utilization and fault tolerance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of current source type inverter, and more particularly to a three-phase full-bridge current source type inverter. BACKGROUND

[0002] With a series of technical breakthroughs in semiconductor and microelectronic technology, power electronic converters have also made great progress and become an indispensable part in the fields of aerospace, industrial production, transportation, etc.

[0003] According to the characteristics of the DC side power supply, the inverter can be divided into voltage source type inverter and current source type inverter. For low inductance motors such as permanent magnet synchronous linear motors, the winding is placed outside the stator under the condition of no core, so the air gap is large and the inductance is very small. If a voltage source type inverter is used for control, the current change rate will be too large, so a current source type inverter is considered for control. Compared with the traditional voltage source type inverter, the research on current source type inverter has been paid more and more attention in recent years.

[0004] However, for the traditional three-phase bridge type current source inverter circuit, the maximum current utilization rate is only 100%, and the fault tolerance performance is poor. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a three-phase full-bridge current source type inverter, which aims to improve the traditional three-phase bridge type current source inverter: in the current source type inverter motor drive system, two power supply bridge arms are arranged for each phase winding, and two power switching tubes are arranged for each power supply bridge arm, which can significantly improve the DC current utilization rate and fault tolerance, thereby solving the technical problems of low current utilization rate and poor fault tolerance of the existing three-phase bridge type current source inverter circuit.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a three-phase full-bridge current source type inverter is provided, comprising: a constant current source, an inductor, an inverter circuit, a capacitor and a three-phase motor; wherein,

[0007] The constant current source is connected in series with the inductor to provide a constant DC current for the inverter;

[0008] The inverter circuit comprises a plurality of power switching tubes for outputting alternating current to drive the three-phase motor;

[0009] The first power supply bridge arm and the second power supply bridge arm of the A-phase winding in the three-phase motor each comprise two power switching tubes; the bridge arm midpoints of the two power supply bridge arms are connected to both ends of the A-phase winding;

[0010] The first power supply bridge arm and the second power supply bridge arm of the B-phase winding of the three-phase motor each include two power switch tubes; the bridge arm midpoints of the two power supply bridge arms are connected to the two ends of the B-phase winding;

[0011] The first power supply bridge arm and the second power supply bridge arm of the C-phase winding of the three-phase motor each include two power switch tubes; the bridge arm midpoints of the two power supply bridge arms are connected to the two ends of the C-phase winding;

[0012] The two ends of the A-phase winding, the B-phase winding and the C-phase winding are each connected in parallel with a capacitor, which can filter the high-frequency PWM current output by the inverter into a sinusoidal current, and when the power switch tube switches, the capacitor is used to provide a current path for the energy stored in the corresponding winding inductance.

[0013] In one embodiment, the plurality of power switch tubes include: power switch tubes S ap1 , S an1 , S ap2 , S an2 , S bp1 , S bn1 , S bp2 , S bn2 , S cp1 , S cn1 , S cp2 and S cn2 ; wherein,

[0014] The power switch tubes S ap1 , S an1 constitute the first power supply bridge arm of the A-phase winding; the power switch tubes S ap2 , S an2 constitute the second power supply bridge arm of the A-phase winding;

[0015] The power switch tubes S bp1 , S bn1 constitute the first power supply bridge arm of the B-phase winding; the power switch tubes S bp2 , S bn2 constitute the second power supply bridge arm of the B-phase winding;

[0016] The power switch tubes S cp1 , S cn1 constitute the first power supply bridge arm of the C-phase winding; the power switch tubes S cp2 , S cn2 constitute the second power supply bridge arm of the C-phase winding.

[0017] In one embodiment, the power switch tube includes a MOSFET and a diode connected in series to ensure unidirectional current flow.

[0018] In one embodiment, the drain of the MOSFET of the power switch S ap1 is connected to the drain of the MOSFET of the power switch S ap2 , and to the positive bus after being stabilized by the current stabilizer; dc

[0019] The negative electrode of the diode of the power switch S ap1 is connected to the drain of the MOSFET of the power switch S an1 ;

[0020] The negative electrode of the diode of the power switch S ap2 is connected to the drain of the MOSFET of the power switch S an2 ;

[0021] The negative electrode of the diode of the power switch S an1 , the negative electrode of the diode of the power switch S an2 , the drain of the MOSFET of the power switch S bp1 , and the drain of the MOSFET of the power switch S bp2 are connected together;

[0022] The negative electrode of the diode of the power switch S bp1 is connected to the drain of the MOSFET of the power switch S bn1 ;

[0023] The negative electrode of the diode of the power switch S bp2 is connected to the drain of the MOSFET of the power switch S bn2 ;

[0024] The negative electrode of the diode of the power switch S bn1 , the negative electrode of the diode of the power switch S bn2 , the drain of the MOSFET of the power switch S cp1 , and the drain of the MOSFET of the power switch S cp2 are connected together;

[0025] The negative electrode of the diode of the power switch S cp1 is connected to the drain of the MOSFET of the power switch S cn1 ;

[0026] The negative electrode of the diode of the power switch S cp2 is connected to the drain of the MOSFET of the power switch S cn2 ;

[0027] The negative electrode of the diode of the power switch S cn1 and the negative electrode of the diode of the power switch S cn2 are connected together, and to the negative bus.​

[0028] In one of the embodiments, the plurality of power switch tubes comprises: power switch tubes S1, S2, S3, S4, S5, S6, S7 and S8; wherein four power switch tubes S3, S4, S5 and S6 are reused;

[0029] The power switch tubes S1 and S3 constitute a first power supply bridge arm of the A-phase winding; the power switch tubes S2 and S4 constitute a second power supply bridge arm of the A-phase winding;

[0030] The power switch tubes S3 and S5 constitute a first power supply bridge arm of the B-phase winding; the power switch tubes S4 and S6 constitute a second power supply bridge arm of the B-phase winding;

[0031] The power switch tubes S5 and S7 constitute a first power supply bridge arm of the C-phase winding; the power switch tubes S6 and S8 constitute a second power supply bridge arm of the C-phase winding.

[0032] In one of the embodiments, the power switch tube comprises a MOSFET and a diode connected in series.

[0033] The drain of the MOSFET of the power switch tube S1 is connected to the drain of the MOSFET of the power switch tube S2, and simultaneously connected to L dc The positive bus after current stabilization is connected;

[0034] The negative electrode of the diode of the power switch tube S1 is connected to the drain of the MOSFET of the power switch tube S3.

[0035] The negative electrode of the diode of the power switch tube S2 is connected to the drain of the MOSFET of the power switch tube S4.

[0036] The negative electrode of the diode of the power switch tube S3 is connected to the drain of the MOSFET of the power switch tube S5.

[0037] The negative electrode of the diode of the power switch tube S4 is connected to the drain of the MOSFET of the power switch tube S6.

[0038] The negative electrode of the diode of the power switch tube S5 is connected to the drain of the MOSFET of the power switch tube S7.

[0039] The negative electrode of the diode of the power switch tube S6 is connected to the drain of the MOSFET of the power switch tube S8.

[0040] The negative electrode of the diode of the power switch tube S7 is connected to the negative electrode of the diode of the power switch tube S8, and simultaneously connected to the negative bus.

[0041] In one of the embodiments, the power switch tube comprises an IGBT and a diode connected in series.

[0042] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0043] (1) The three-phase full-bridge current source inverter provided by the present application is improved on the basis of the traditional three-phase bridge current source inverter: in the current source inverter motor drive system, two power supply bridge arms are arranged for each phase winding, and two power switching tubes are arranged for each power supply bridge arm. Compared with the 100% maximum DC current utilization rate of the traditional three-phase bridge current source inverter circuit, the A, B and C phase windings of the three-phase motor can simultaneously circulate a current of I dc , and the maximum DC current utilization rate is significantly increased. In addition, the present application can perform fault-tolerant control, and when any power device in the plurality of power switching tubes fails due to short circuit or open circuit, the motor can still maintain a certain operating ability, and the fault tolerance is also significantly improved.

[0044] (2) The A, B and C phase windings of the three-phase motor can simultaneously circulate a current of I dc , and the maximum DC current utilization rate is 115%, compared with the maximum DC current utilization rate of 100% of the traditional current source inverter three-phase bridge topology, and the DC current utilization rate is significantly improved. When any power device in the S ap1 ~ S cn2 fails due to short circuit or open circuit, the three-phase motor can still maintain a certain operating ability: for example, when S ap1 fails due to open circuit, S ap2 and S an2 are always on, S an1 is always off, there is no current in the A phase winding at all times, and the freedom of the B and C phase windings is fully utilized, so the three-phase motor can still operate, and the fault tolerance is significantly improved.

[0045] (3) The above three-phase full-bridge current source inverter is switched for multiplexing, to obtain a simplified three-phase full-bridge current source inverter, which only needs 8 power switching tubes. At this time, when any power device in S1, S2, S7 and S8 fails due to short circuit or open circuit, the three-phase motor can still maintain a certain operating ability: for example, when S1 fails due to short circuit, S2 is always off, and the three-phase motor can still operate by utilizing the remaining freedom, which reduces the number of power switching tubes while also having partial fault tolerance capability. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is the circuit diagram of the three-phase full-bridge current source inverter in Embodiment 2 of the present application.

[0047] Figure 2 is the circuit diagram of the three-phase full-bridge current source inverter in Embodiment 5 of the present application.

[0048] Figure 3 This is the current vector space diagram of the three-phase full-bridge current source inverter in Embodiment 7 of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0050] Example 1

[0051] This invention provides a three-phase full-bridge current source inverter, comprising: a constant current source, an inductor, multiple power switching transistors, a capacitor, and a three-phase motor; wherein,

[0052] A constant current source is connected in series with an inductor to provide a constant DC current to the inverter;

[0053] The inverter circuit includes multiple power switches for outputting AC current to drive the three-phase motor; each power switch is used to ensure unidirectional current flow.

[0054] In a three-phase motor, the first and second power supply bridge arms of the A-phase winding each include two power switching transistors; the midpoint of the two power supply bridge arms is connected to both ends of the A-phase winding.

[0055] In a three-phase motor, the first and second power supply bridge arms of the B-phase winding each include two power switching transistors; the midpoint of the two power supply bridge arms is connected to both ends of the B-phase winding.

[0056] In a three-phase motor, the first and second power supply bridge arms of the C-phase winding each include two power switching transistors; the midpoints of the two power supply bridge arms are connected to both ends of the C-phase winding.

[0057] A capacitor is connected in parallel across both ends of the A-phase winding, the B-phase winding, and the C-phase winding. The capacitor can filter the high-frequency PWM current output by the inverter into a sinusoidal current, and when the power switch switches, the capacitor is used to provide a current path for the energy stored in the corresponding winding inductance.

[0058] Example 2

[0059] like Figure 1 As shown, the multiple power switching transistors include: power switching transistor S ap1 S an1 S ap2 San2 , S bp1 , S bn1 , S bp2 , S bn2 , S cp1 , S cn1 , S cp2 and S cn2 ; wherein,

[0060] power switch S ap1 , S an1 constitute a first power supply bridge arm of the A-phase winding; power switch S ap2 , S an2 constitute a second power supply bridge arm of the A-phase winding;

[0061] power switch S bp1 , S bn1 constitute a first power supply bridge arm of the B-phase winding; power switch S bp2 , S bn2 constitute a second power supply bridge arm of the B-phase winding;

[0062] power switch S cp1 , S cn1 constitute a first power supply bridge arm of the C-phase winding; power switch S cp2 , S cn2 constitute a second power supply bridge arm of the C-phase winding.

[0063] In particular, the embodiment provides a three-phase full-bridge current source type inverter, comprising a constant current source I dc , an inductor L dc , 12 power switches and 3 capacitors.

[0064] power switch S ap1 , S an1 constitute a first power supply bridge arm of the A-phase winding of the three-phase motor; power switch S ap2 , S an2 constitute a second power supply bridge arm of the A-phase winding of the three-phase motor; the bridge arm midpoints of the two power supply bridge arms are connected to the two ends of the A-phase winding.

[0065] power switch S bp1 , S bn1 constitute a first power supply bridge arm of the B-phase winding of the three-phase motor; power switch S bp2 , S bn2 constitute a second power supply bridge arm of the B-phase winding of the three-phase motor; the bridge arm midpoints of the two power supply bridge arms are connected to the two ends of the B-phase winding.

[0066] power switch S cp1 , S cn1The first power supply bridge arm constituting the C-phase winding of a three-phase motor; power switch S cp2 S cn2 The second power supply bridge arm constitutes the C-phase winding of the three-phase motor; the midpoint of the two power supply bridge arms is connected to both ends of the C-phase winding.

[0067] A capacitor of appropriate capacitance is connected in parallel across the A-phase winding of a three-phase motor. Since the current output by the two power supply bridge arms corresponding to the A-phase winding is a high-frequency square wave, the capacitor can filter out harmonics to obtain a sinusoidal current; and when a switching transistor switches, such as S... ap1 and S an2 Switching to S ap2 and S an2 When the circuit is turned on, the capacitor provides a current path for the energy stored in the motor inductance; otherwise, very high voltage spikes may be generated, causing damage to the power switching devices.

[0068] A capacitor of appropriate capacitance is connected in parallel across the B-phase winding of the three-phase motor. Since the current output by the two power supply bridge arms corresponding to the B-phase winding is a high-frequency square wave, the capacitor can filter out harmonics to obtain a sinusoidal current; and when a switching transistor switches, such as S... bp1 and S bn2 Switching to S bp2 and S bn2 When the circuit is turned on, the capacitor provides a current path for the energy stored in the motor inductance; otherwise, very high voltage spikes may be generated, causing damage to the power switching devices.

[0069] A capacitor of appropriate capacitance is connected in parallel across the C-phase winding of a three-phase motor. Since the current output from the two power supply bridge arms corresponding to the C-phase winding is a high-frequency square wave, the capacitor can filter out harmonics to obtain a sinusoidal current; and when a switching transistor switches, such as S... cp1 and S cn2 Switching to S cp2 and S cn2 When the circuit is turned on, the capacitor provides a current path for the energy stored in the motor inductance; otherwise, very high voltage spikes may be generated, causing damage to the power switching devices.

[0070] Example 3

[0071] Power switching devices consist of a MOSFET and a diode connected in series.

[0072] Example 4

[0073] Power switch S ap1 The drain of the MOSFET and the power switch S ap2 The drain of the MOSFET is connected to L. dc Connect it to the positive bus after current stabilization. Power switch S ap1 The cathode of the diode is connected to the power switch S.an1 The drain of the MOSFET is connected, and the power switch S ap2 The cathode of the diode is connected to the power switch S. an2 The drain of the MOSFET is connected. Power switch S an1 The cathode of the diode, the power switch S an2 The cathode of the diode, the power switch S bp1 The drain of the MOSFET and the power switch S bp2 The drains of the MOSFETs are connected in a four-way connection. Power switch S bp1 The cathode of the diode is connected to the power switch S. bn1 The drain of the MOSFET is connected, and the power switch S bp2 The cathode of the diode is connected to the power switch S. bn2 The drain of the MOSFET is connected. Power switch S bn1 The cathode of the diode, the power switch S bn2 The cathode of the diode, the power switch S cp1 The drain of the MOSFET and the power switch S cp2 The drains of the MOSFETs are connected in a four-way connection. Power switch S cp1 The cathode of the diode is connected to the power switch S. cn1 The drain of the MOSFET is connected, and the power switch S cp2 The cathode of the diode is connected to the power switch S. cn2 The drain of the MOSFET is connected. Power switch S cn1 The cathode of the diode and the power switch S cn2 The negative terminal of the diode is connected to the negative busbar.

[0074] Example 5

[0075] like Figure 2 As shown, the multiple power switching transistors include: power switching transistors S1, S2, S3, S4, S5, S6, S7 and S8;

[0076] Power switches S1 and S3 form the first power supply bridge arm of phase A winding; power switches S2 and S4 form the second power supply bridge arm of phase A winding.

[0077] Power switches S3 and S5 form the first power supply bridge arm of the B-phase winding; power switches S4 and S6 form the second power supply bridge arm of the B-phase winding.

[0078] Power switches S5 and S7 form the first power supply bridge arm of the C-phase winding; power switches S6 and S8 form the second power supply bridge arm of the C-phase winding.

[0079] Example 6

[0080] The drain of the MOSFET of the power switch S1 is connected to the drain of the MOSFET of the power switch S2, and is connected to L dc The positive bus after current stabilization is connected. The power switches S3, S4, S5 and S6 are multiplexed. The negative electrode of the diode of the power switch S1 is connected to the drain of the MOSFET of the power switch S3. The negative electrode of the diode of the power switch S2 is connected to the drain of the MOSFET of the power switch S4. The negative electrode of the diode of the power switch S3 is connected to the drain of the MOSFET of the power switch S5. The negative electrode of the diode of the power switch S4 is connected to the drain of the MOSFET of the power switch S6. The negative electrode of the diode of the power switch S5 is connected to the drain of the MOSFET of the power switch S7. The negative electrode of the diode of the power switch S6 is connected to the drain of the MOSFET of the power switch S8. The negative electrode of the diode of the power switch S7 and the negative electrode of the diode of the power switch S8 are connected, and are connected to the negative bus.

[0081] Embodiment 7

[0082] Figure 3 The current vector space diagram of the three-phase full-bridge current source inverter described in the present application. Among them The non-zero middle vector possessed by the traditional three-phase bridge current source inverter, that is, one of the A, B and C three-phase bridge arms outputs current I dc , one of the A, B and C three-phase bridge arms outputs current -I dc , and the other two-phase bridge arms output current 0. And The non-zero small vector and non-zero large vector unique to the three-phase full-bridge current source inverter proposed in the present application. Representing the case that one of the A, B and C three-phase bridge arms outputs current I dc or -I dc , and the other two-phase bridge arms output current 0. Representing the case that one of the A, B and C three-phase bridge arms outputs current I dc , and the other two-phase bridge arms output current -I dc , or one of the A, B and C three-phase bridge arms outputs current -I dc , and the other two-phase bridge arms output current I dc .

[0083] Embodiment 8

[0084] The power switch includes an IGBT and a diode connected in series.

[0085] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A three-phase full-bridge current-source inverter, characterized by comprising: include: Constant current source, inductor, inverter circuit, capacitor, and three-phase motor; among them, The constant current source is connected in series with the inductor to provide a constant DC current to the inverter; The inverter circuit includes multiple power switching transistors for outputting AC current to drive the three-phase motor; In the three-phase motor, a capacitor is connected in parallel to both ends of the A-phase winding, the B-phase winding, and the C-phase winding; Power switch S ap1 , S an1 A first power supply bridge arm constituting the A-phase winding; the power switch S ap2 , S an2 A second power supply bridge arm constituting the A-phase winding; the bridge arm midpoints of the two power supply bridge arms are connected to the two ends of the A-phase winding Power switch S bp1 , S bn1 The first power supply bridge arm of the B-phase winding; the power switch S bp2 , S bn2 The second power supply bridge arm of the B-phase winding; the bridge arm midpoint of the two power supply bridge arms is connected with the two ends of the B-phase winding Power switch S cp1 , S cn1 The first power supply bridge arm of the C-phase winding; the power switch S cp2 , S cn2 The second power supply bridge arm of the C-phase winding; the bridge arm midpoint of the two power supply bridge arms is connected with the two ends of the C-phase winding. Power switch S ap1 The drain of the MOSFET of the power switch S ap2 The drain of the MOSFET of the power switch S is connected to the drain of the MOSFET of the power switch S, and simultaneously to L dc The positive bus after the current stabilization is connected. Power switch S ap1 The negative pole of the diode of power switch S an1 is connected with the drain of the MOSFET of power switch S Power switch S ap2 The negative pole of the diode of the power switch S an2 is connected with the drain of the MOSFET of the power switch S the drain of the MOSFET of the power switch S an1 the anode of the diode of the power switch S an2 the anode of the diode of the power switch S bp1 the drain of the MOSFET of the power switch S bp2 the drain of the MOSFET of the power switch S Power switch S bp1 The negative pole of the diode of power switch S bn1 is connected with the drain of the MOSFET of power switch S Power switch S bp2 The negative pole of the diode of power switch S bn2 is connected with the drain of the MOSFET of power switch S the drain of the MOSFET of the power switch S bn1 the anode of the diode of the power switch S bn2 the anode of the diode of the power switch S cp1 the drain of the MOSFET of the power switch S cp2 the drain of the MOSFET of the power switch S Power switch S cp1 The negative pole of the diode of power switch S cn1 is connected with the drain of the MOSFET of power switch S Power switch S cp2 The negative pole of the diode of power switch S cn2 is connected with the drain of the MOSFET of power switch S The anode of the diode of the power switch S cn1 The anode of the diode of the power switch S cn2 is connected to the negative bus.

2. The three-phase full-bridge current-source inverter as claimed in claim 1, characterized in that, The power switch includes a MOSFET and a diode connected in series to ensure unidirectional current flow.

3. The three-phase full-bridge current-source inverter according to claim 1 or 2, characterized in that, The power switch includes an IGBT and a diode connected in series to ensure unidirectional current flow.

4. A three-phase full-bridge current-source inverter, characterized by comprising: include: Constant current source, inductor, inverter circuit, capacitor, and three-phase motor; among them, The constant current source is connected in series with the inductor to provide a constant DC current to the inverter; The inverter circuit includes multiple power switching transistors for outputting AC current to drive the three-phase motor; In the three-phase motor, a capacitor is connected in parallel to both ends of the A-phase winding, the B-phase winding, and the C-phase winding; Power switches S1 and S3 form the first power supply bridge arm of the A-phase winding; power switches S2 and S4 form the second power supply bridge arm of the A-phase winding; the midpoint of the two power supply bridge arms is connected to both ends of the A-phase winding. Power switches S3 and S5 form the first power supply bridge arm of the B-phase winding; power switches S4 and S6 form the second power supply bridge arm of the B-phase winding; the midpoint of the two power supply bridge arms is connected to both ends of the B-phase winding. Power switches S5 and S7 form the first power supply bridge arm of the C-phase winding; power switches S6 and S8 form the second power supply bridge arm of the C-phase winding; the midpoint of the two power supply bridge arms is connected to both ends of the C-phase winding. The drain of the MOSFET of the power switch S1 is connected to the drain of the MOSFET of the power switch S2, and simultaneously to the positive bus after smoothing. L dc The positive bus after smoothing. The cathode of the diode in power switch S1 is connected to the drain of the MOSFET in power switch S3. The cathode of the diode in power switch S2 is connected to the drain of the MOSFET in power switch S4. The cathode of the diode in power switch S3 is connected to the drain of the MOSFET in power switch S5. The cathode of the diode in power switch S4 is connected to the drain of the MOSFET in power switch S6. The cathode of the diode in power switch S5 is connected to the drain of the MOSFET in power switch S7. The cathode of the diode in power switch S6 is connected to the drain of the MOSFET in power switch S8. The negative terminals of the diodes of power switch S7 and S8 are connected, and are also connected to the negative bus.

5. The three-phase full-bridge current-source inverter according to claim 4, characterized in that, The power switch includes a MOSFET and a diode connected in series to ensure unidirectional current flow.

6. The three-phase full-bridge current-source inverter according to claim 4 or 5, characterized in that, The power switch includes an IGBT and a diode connected in series to ensure unidirectional current flow.

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