A control method for a six-switch matrix converter

Abstract

The present invention discloses a control method for a six-switch matrix converter. Taking into account the voltage and frequency regulation requirements of an AC-AC converter and the inherent characteristics of the six-switch matrix converter, different PWM signals are applied in stages to the six switches of the six-switch matrix converter when the AC power supply outputs forward and reverse voltages, placing the six-switch matrix converter in different modes. By adjusting the duty cycle of the PWM signal, the voltage gain is increased or decreased, and the output voltage is adjusted to be in phase or out of phase with the input voltage, thereby adjusting the frequency, achieving the frequency modulation required by the AC-AC converter. The control method is simple and easy to operate, broadening the application of the six-switch matrix converter.

Description

Technical Field

[0001] The present invention belongs to the field of power electronic converters, and in particular relates to a control method for a six-switch matrix converter. Background Art

[0002] With the development of society, energy crises and environmental pollution are becoming increasingly serious. Consequently, topics such as renewable energy generation and electric vehicles have become research hotspots. Power electronics converters, as the core technology behind these technologies, have become a key research focus for researchers in related fields. AC-AC converters, a crucial component of power electronics technology, are at the core of technologies such as AC power supplies, transformers, and renewable energy power generation equipment, and are currently being widely studied.

[0003] With the development of AC-AC converters, they can be divided into AC-DC-AC converters and AC-AC converters according to whether or not there is an intermediate energy storage link. Due to the presence of a large energy storage element, the AC-DC-AC converter is relatively large in size and is not suitable for high-power applications. Compared with AC-DC-AC converters, traditional AC-AC converters have the advantages of no intermediate energy storage link, small size, low cost, and easy integration. As a type of AC-AC converter, the matrix converter also has the advantages of adjustable power factor, bidirectional energy flow, and high power density.

[0004] As global requirements for energy efficiency and energy conservation continue to increase in recent years, along with the continuous improvement of switching tube performance, the requirements for power electronic converters in various applications have continued to increase. Matrix converters, as a converter with superior performance, have become a research hotspot. Currently, traditional direct-change AC-AC converters can adjust the AC voltage by increasing or decreasing the voltage, but cannot change the frequency. Indirect-change AC-DC-AC converters can change the frequency, but their large size remains unresolved. While some matrix converters can achieve voltage and frequency adjustment, they still suffer from cumbersome control strategies, limited voltage transfer ratios, and severe commutation issues. Summary of the Invention

[0005] The object of the present invention is to provide a control method based on a six-switch matrix converter for realizing the conversion of alternating current, and can directly realize the functions of voltage and frequency by changing the duty cycle of the PWM control waveform.

[0006] In order to achieve the above object, the present invention provides a control method for a six-switch matrix converter, wherein the six-switch matrix converter includes a first switch tube S1, a second switch tube S2, a third switch tube S3, a fourth switch tube S4, a fifth switch tube S5 and a sixth switch tube S6, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6, an input AC voltage source V in , input filter capacitor C in , inductor L, output filter capacitor C o and load R L ;

[0007] The source of the first switching transistor S1 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the drain of the third switching transistor S3, the source of the third switching transistor S3 is connected to the anode of the third diode D3, the cathode of the third diode D3 is connected to the drain of the fifth switching transistor S5, the source of the fifth switching transistor S5 is connected to the anode of the fifth diode D5, the source of the second switching transistor S2 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to the drain of the fourth switching transistor S4, the source of the fourth switching transistor S4 is connected to the anode of the fourth diode D4, the cathode of the fourth diode D4 is connected to the drain of the sixth switching transistor S6, and the source of the sixth switching transistor S6 is connected to the anode of the sixth diode D6;

[0008] The drain of the first switching transistor S1 is connected to the drain of the second switching transistor S2, the cathode of the fifth diode D5 is connected to the cathode of the sixth diode D6, and the connection point between the first switching transistor S1 and the second switching transistor S2 and the connection point between the fifth diode D5 and the sixth diode D6 are respectively connected to the two ends of the inductor L;

[0009] The connection point between the third switch tube S3 and the first diode D1 and the connection point between the fourth switch tube S4 and the second diode D2 are connected to the input filter capacitor C in Connect both ends of the AC voltage source V in and the input filter capacitor C in in parallel;

[0010] The connection point between the third diode D3 and the fifth switch S5 and the connection point between the fourth diode D4 and the sixth switch S6 are connected to the output filter capacitor C o The two ends of the load R L and the output filter capacitor C o in parallel;

[0011] The control method is specifically as follows:

[0012] When the connection point between the third switch tube S3 and the first diode D1 is at a high potential and the connection point between the fourth switch tube S4 and the second diode D2 is at a low potential, the voltage input by the input voltage source is a forward voltage, otherwise it is a reverse voltage;

[0013] For the converter duty cycle T when the input voltage is a positive voltage, the duty cycle of the PWM signal is set to d1 and divided into two time periods 0 to d1T and d1T to T;

[0014] When the input voltage is a positive voltage, the second switch tube S2 remains in the on state, and a PWM conduction signal with a duty cycle of d1 is applied to the third switch tube S3 and the sixth switch tube S6. A PWM conduction signal with a duty cycle of 1-d1, which is complementary to that of the third switch tube S3 and the sixth switch tube S6, is applied to the fourth switch tube S4 and the fifth switch tube S5.

[0015] For the converter duty cycle T when the input voltage is a reverse voltage, the duty cycle of the PWM signal is set to d2, which is divided into two time periods: 0 to d2T and d2T to T;

[0016] When the input voltage is a reverse voltage, the first switch tube S1 remains in the on state, and a PWM conduction signal with a duty cycle of d2 is applied to the fourth switch tube S4 and the fifth switch tube S5. A PWM conduction signal with a duty cycle of 1-d2 complementary to that of the fourth switch tube S4 and the fifth switch tube S5 is applied to the third switch tube S3 and the sixth switch tube S6.

[0017] Preferably, when the converter operates from 0 to d1T, the converter is driven by the input AC voltage source V in , the third switch tube S3, the third diode D3, the output filter capacitor C o , the sixth switch tube S6, the sixth diode D6, the inductor L, the second switch tube S2 and the second diode D2 form a loop;

[0018] When the converter works from d1T to T, the output filter capacitor C o , the fifth switch tube S5, the fifth diode D5, the inductor L, the second switch tube S2, the second diode D2, the fourth switch tube S4 and the fourth diode D4 form a loop;

[0019] When the converter operates from 0 to d2T, the converter is fed by the input AC voltage source V in , the fourth switch tube S4, the fourth diode D4, the output filter capacitor C o , the fifth switch tube S5, the fifth diode D5, the inductor L, the first switch tube S1 and the first diode D1 form a loop;

[0020] When the converter works from d2T to T, the output filter capacitor C o, the sixth switch tube S6 , the sixth diode D6 , the inductor L, the first switch tube S1 , the first diode D1 , the third switch tube S3 and the third diode D3 form a loop.

[0021] Preferably, when the converter operates from 0 to d1T, the input voltage is positive, the connection point between the first switch S1 and the second switch S2 at both ends of the inductor is set to a high potential, the connection point between the fifth diode D5 and the sixth diode D6 is set to a low potential, the output voltage is in phase with the input voltage, that is, the connection point between the third diode D3 and the fifth switch S5 is set to a high potential, and the connection point between the fourth diode D4 and the sixth switch S6 is set to a low potential, then the volt-second product of the inductor L is d1T (V in -V o ), when the converter operates from d1T to T, the volt-second product of the inductor is (1-d1)TV o , then according to the volt-second balance d1T (V in -V o )+(1-d1)TV o =0, then the converter gain M is expressed as:

[0022]

[0023] When the converter operates from 0 to d2T, the input voltage is in the reverse direction. The connection point between the first switch S1 and the second switch S2 at both ends of the inductor is still set to a high potential, and the connection point between the fifth diode D5 and the sixth diode D6 is set to a low potential. The output voltage is in phase with the input voltage, that is, the connection point between the third diode D3 and the fifth switch S5 is a low potential, and the connection point between the fourth diode D4 and the sixth switch S6 is a high potential. Then the volt-second product of the inductor L is d2T (V in -V o ), when the converter operates from d2T to T, the volt-second product of the inductor is (1-d2)TV o , then according to the volt-second balance d2T (V in -V o )+(1-d2)TV o =0, then the converter gain M is expressed as:

[0024]

[0025] Preferably, when a forward voltage is input, when the duty cycle d1 is between 0.5 and 1, the voltage gain M is positive, the output voltage is positive, and is in phase with the input voltage, belonging to the forward voltage in-phase output mode; when the duty cycle d1 is between 0 and 0.5, the voltage gain M is negative, the output voltage is reverse, and is in phase with the input voltage, belonging to the forward voltage inverse output mode;

[0026] When a reverse voltage is input, when the duty cycle d2 is between 0.5 and 1, the voltage gain M is positive, the output voltage is negative, and is in phase with the input voltage, which belongs to the reverse voltage in-phase output mode. When the duty cycle d1 is between 0 and 0.5, the voltage gain M is negative, the output voltage is negative, and is in phase with the input voltage, which belongs to the reverse voltage inverting output mode.

[0027] Preferably, when the converter operating mode belongs to the in-phase output, regardless of whether the input voltage is forward or reverse, the duty cycle is in the range of 0.5 to 1. At this time, the voltage gain M ranges from 1 to positive infinity, achieving different levels of boost;

[0028] When the converter operates in inverting output mode, the duty cycle is in the range of 0 to 0.5 regardless of whether the input voltage is forward or reverse. At this time, the voltage gain M ranges from negative infinity to 0, achieving different levels of boost and buck.

[0029] Compared with the prior art, the present invention has the following significant advantages: (1) in view of the characteristics of the six-switch matrix converter, the proposed control strategy is consistent with the symmetry of the six-switch matrix converter, the required switch tube drive also shows symmetry, and the control scheme is simple; (2) the present invention can simultaneously adjust the magnitude and frequency of the AC voltage, and can be applied to occasions where the magnitude and frequency of the AC voltage need to be changed at the same time, such as controlling the speed of a fan, driving an induction motor, etc.; (3) compared with the commonly used control strategy of the six-switch matrix converter, which needs to consider eight modes of the converter, the present invention only needs to consider four modes of the converter, and voltage and frequency regulation can be completed simultaneously by changing one variable, the duty cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the basic circuit topology diagram of the six-switch matrix converter.

[0031] Figure 2 It is the circuit modal diagram when the input voltage is positive and the converter operates from 0 to d1T.

[0032] Figure 3 It is the circuit modal diagram when the input voltage is positive and the converter operates from d1T to T.

[0033] Figure 4 It is the circuit modal diagram when the input voltage is negative and the converter operates from 0 to d2T.

[0034] Figure 5 It is the circuit modal diagram when the input voltage is negative and the converter operates from d2T to T.

[0035] Figure 6 It is a variable relationship diagram of duty cycle and voltage gain.

[0036] Figure 7This is the operating waveform of the converter with an input voltage of 100V / 50Hz and an output voltage of 200V / 25Hz.

[0037] Figure 8 This is the output voltage simulation waveform diagram with an input voltage of 100V / 50Hz and an output voltage of 200V / 25Hz.

[0038] Figure 9 This is the operating waveform of the converter with an input voltage of 100V / 50Hz and an output voltage of 200V / 16.7Hz.

[0039] Figure 10 This is the output voltage simulation waveform diagram with an input voltage of 100V / 50Hz and an output voltage of 200V / 16.7Hz. DETAILED DESCRIPTION

[0040] A control method for a six-switch matrix converter, wherein the specific topology of the six-switch matrix converter is as follows: Figure 1 As shown, it includes six switching tubes, six diodes, and an input AC voltage source V in , input filter capacitor C in , inductor L, output filter capacitor C o and load R L Furthermore, the six-switch matrix converter mentioned above has a symmetrical structure, and therefore the converter operating modes in the positive and negative directions of the input voltage are also symmetrical.

[0041] For the control method mentioned above, it is stipulated that the voltage input by the input voltage source is a forward voltage when it is positive at the top and negative at the bottom, and a reverse voltage otherwise; for the converter working period T when the input voltage is a forward voltage, the duty cycle of the PWM signal is set to d1 and divided into two time periods 0 to d1T and d1T to T; for the converter working period T when the input voltage is a reverse voltage, the duty cycle of the PWM signal is set to d2 and divided into two time periods 0 to d2T and d2T to T; the converter operation will have four modes, which are related to the four working time periods, namely the mentioned 0 to d1T, d1T to T, 0 to d2T and d2T to T.

[0042] When the input voltage is a positive voltage, the second switch tube S2 remains in the on state, and a PWM conduction signal with a duty cycle of d1 is applied to the third switch tube S3 and the sixth switch tube S6. The corresponding converter mode diagram is shown as follows Figure 2 As shown; a PWM conduction signal with a duty cycle of 1-d1 complementary to the third switch tube S3 and the sixth switch tube S6 is applied to the fourth switch tube S4 and the fifth switch tube S5, and the corresponding converter mode diagram is shown as follows Figure 3 As shown; when the converter works from 0 to d1T, the converter is input by the AC voltage source V in , the third switch tube S3, the third diode D3, the output filter capacitor Co , the sixth switch tube S6, the sixth diode D6, the inductor L, the second switch tube S2 and the second diode D2 form a loop. When the converter works from d1T to T, the converter is connected to the output filter capacitor C o , the fifth switch tube S5, the fifth diode D5, the inductor L, the second switch tube S2, the second diode D2, the fourth switch tube S4 and the fourth diode D4 form a loop.

[0043] When the input voltage is a reverse voltage, the first switch tube S1 remains on, and a PWM conduction signal with a duty cycle of d2 is applied to the fourth switch tube S4 and the fifth switch tube S5. The corresponding converter mode diagram is as follows Figure 4 As shown; a PWM conduction signal with a duty cycle of 1-d2 complementary to that of the fourth switch tube S4 and the fifth switch tube S5 is applied to the third switch tube S3 and the sixth switch tube S6, and the corresponding converter mode diagram is shown as follows Figure 5 As shown; when the converter works in 0 to d2T, the converter is input by the AC voltage source V in , the fourth switch tube S4, the fourth diode D4, the output filter capacitor C o , the fifth switch tube S5, the fifth diode D5, the inductor L, the first switch tube S1 and the first diode D1 form a loop. When the converter works at d2T to T, the converter is connected to the output filter capacitor C o , the sixth switch tube S6 , the sixth diode D6 , the inductor L, the first switch tube S1 , the first diode D1 , the third switch tube S3 and the third diode D3 form a loop.

[0044] When the control method proposed by the present invention is used, the voltage gain of the converter is fixed at:

[0045]

[0046] Where d is the duty cycle, which is d1 when the input is forward voltage and d2 when the input is reverse voltage.

[0047] The relationship between voltage gain M and duty cycle d is shown in the figure below: Figure 6 As shown, regardless of whether the input voltage is forward or reverse, when the duty cycle is in the range of 0.5 to 1, the voltage gain M ranges from 1 to positive infinity, and the converter working mode belongs to the in-phase output, which can achieve different levels of boost; when the duty cycle is in the range of 0 to 0.5, the voltage gain M ranges from negative infinity to 0, and the converter working mode belongs to the inverting output, which can achieve different levels of boost and buck.

[0048] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0049] The input voltage waveform is specified as a sine wave with an amplitude of 100V and a frequency of 50Hz. For example, the output voltage waveform is controlled to have an amplitude of 200V and a frequency of 25Hz, and an amplitude of 200V and a frequency of 16.7Hz.

[0050] If we want to output a waveform with a voltage amplitude of 200V and a frequency of 25Hz, we first consider the output voltage amplitude. When the output voltages are in-phase, the voltage gain M is 2. Using the voltage gain formula, we can inversely calculate the duty cycle to be 0.67. When the output voltages are in-phase, the voltage gain M is -2. Similarly, using the voltage gain formula, we can inversely calculate the duty cycle to be 0.4. For a 50Hz sine wave, one sine cycle is 0.02 seconds. We need to consider which portions of the waveform are output in-phase and which are output in reverse. Adjusting the output frequency to 25Hz doubles the period to 0.04 seconds, resulting in two complete sine cycles. During this period, the forward voltage from 0 seconds to 0.01 seconds and the reverse voltage from 0.03 seconds to 0.04 seconds are output in-phase. The reverse voltage from 0.01 seconds to 0.02 seconds and the forward voltage from 0.02 seconds to 0.03 seconds are output in reverse.

[0051] For each large cycle of 0.04 seconds, the corresponding switching tube operating waveform is as follows Figure 7 As shown:

[0052] From 0 seconds to 0.01 seconds, the second switch S2 is constantly turned on, a PWM wave with a duty cycle of 0.67 is applied to the third switch S3 and the sixth switch S6, and a PWM wave complementary to the control waveforms of the third switch S3 and the sixth switch S6 is applied to the fourth switch S4 and the fifth switch S5;

[0053] From 0.01 seconds to 0.02 seconds, the first switch S1 is constantly turned on, a PWM wave with a duty cycle of 0.4 is applied to the fourth switch S4 and the fifth switch S5, and a PWM wave complementary to the control waveforms of the fourth switch S4 and the fifth switch S5 is applied to the third switch S3 and the sixth switch S6;

[0054] From 0.02 seconds to 0.03 seconds, the second switch S2 is constantly turned on, a PWM wave with a duty cycle of 0.4 is applied to the third switch S3 and the sixth switch S6, and a PWM wave complementary to the control waveforms of the third switch S3 and the sixth switch S6 is applied to the fourth switch S4 and the fifth switch S5;

[0055] From 0.03 seconds to 0.04 seconds, the first switch S1 is constantly turned on, a PWM wave with a duty cycle of 0.67 is applied to the fourth switch S4 and the fifth switch S5, and a PWM wave complementary to the control waveforms of the fourth switch S4 and the fifth switch S5 is applied to the third switch S3 and the sixth switch S6.

[0056] The output voltage simulation waveform of converting the input voltage of 100V / 50Hz to the output voltage of 200V / 25Hz is as follows Figure 8 shown.

[0057] If a waveform with a voltage amplitude of 200V and a frequency of 16.7Hz is to be output, the voltage amplitude and duty cycle calculation are the same as for the waveform with a voltage amplitude of 200V and a frequency of 25Hz. Consider adjusting a 50Hz waveform to a 16.7Hz waveform. The original period is 0.02 seconds. Adjusting the output frequency to 16.7Hz triples the original period to 0.06 seconds, resulting in three complete sine cycles. Within this period, the forward voltage from 0 to 0.01 seconds and from 0.02 to 0.03 seconds, as well as the reverse voltage from 0.03 to 0.04 seconds and from 0.05 to 0.06 seconds, must be output in phase. The reverse voltage from 0.01 to 0.02 seconds and the forward voltage from 0.04 to 0.05 seconds must be output in reverse phase.

[0058] For each large cycle of 0.06 seconds, the corresponding switching tube operating waveform is as follows Figure 9 As shown:

[0059] From 0 seconds to 0.01 seconds, the second switch S2 is constantly turned on, a PWM wave with a duty cycle of 0.67 is applied to the third switch S3 and the sixth switch S6, and a PWM wave complementary to the control waveforms of the third switch S3 and the sixth switch S6 is applied to the fourth switch S4 and the fifth switch S5;

[0060] From 0.01 seconds to 0.02 seconds, the first switch S1 is constantly turned on, a PWM wave with a duty cycle of 0.4 is applied to the fourth switch S4 and the fifth switch S5, and a PWM wave complementary to the control waveforms of the fourth switch S4 and the fifth switch S5 is applied to the third switch S3 and the sixth switch S6;

[0061] The control waveform from 0.02s to 0.03s is the same as that from 0s to 0.01s;

[0062] From 0.03 seconds to 0.04 seconds, the first switch S1 is constantly turned on, a PWM wave with a duty cycle of 0.67 is applied to the fourth switch S4 and the fifth switch S5, and a PWM wave complementary to the control waveforms of the fourth switch S4 and the fifth switch S5 is applied to the third switch S3 and the sixth switch S6;

[0063] From 0.04 seconds to 0.05 seconds, the second switch S2 is constantly turned on, a PWM wave with a duty cycle of 0.4 is applied to the third switch S3 and the sixth switch S6, and a PWM wave complementary to the control waveforms of the third switch S3 and the sixth switch S6 is applied to the fourth switch S4 and the fifth switch S5;

[0064] The control waveforms from 0.05 seconds to 0.06 seconds are the same as those from 0.03 seconds to 0.04 seconds.

[0065] The output voltage simulation waveform of converting the input voltage of 100V / 50Hz to the output voltage of 200V / 16.7Hz is as follows Figure 10 shown.

[0066] The above two examples are only two cases where the control method has a better effect. The function of the control method is not limited to the above two cases of voltage and frequency conversion.

Claims

1. A control method for a six-switch matrix converter, characterized in that: The six-switch matrix converter includes a first switch tube S1, a second switch tube S2, a third switch tube S3, a fourth switch tube S4, a fifth switch tube S5 and a sixth switch tube S6, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6, an input AC voltage source V in , input filter capacitor C in , inductor L, output filter capacitor C o and load R L ; The source of the first switching transistor S1 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the drain of the third switching transistor S3, the source of the third switching transistor S3 is connected to the anode of the third diode D3, the cathode of the third diode D3 is connected to the drain of the fifth switching transistor S5, the source of the fifth switching transistor S5 is connected to the anode of the fifth diode D5, the source of the second switching transistor S2 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to the drain of the fourth switching transistor S4, the source of the fourth switching transistor S4 is connected to the anode of the fourth diode D4, the cathode of the fourth diode D4 is connected to the drain of the sixth switching transistor S6, and the source of the sixth switching transistor S6 is connected to the anode of the sixth diode D6; The drain of the first switching transistor S1 is connected to the drain of the second switching transistor S2, the cathode of the fifth diode D5 is connected to the cathode of the sixth diode D6, and the connection point between the first switching transistor S1 and the second switching transistor S2 and the connection point between the fifth diode D5 and the sixth diode D6 are respectively connected to the two ends of the inductor L; The connection point between the third switch tube S3 and the first diode D1 and the connection point between the fourth switch tube S4 and the second diode D2 are connected to the input filter capacitor C in Connect both ends of the AC voltage source V in and the input filter capacitor C in in parallel; The connection point between the third diode D3 and the fifth switch S5 and the connection point between the fourth diode D4 and the sixth switch S6 are connected to the output filter capacitor C o The two ends of the load R L and the output filter capacitor C o in parallel; The control method is specifically as follows: When the connection point between the third switch tube S3 and the first diode D1 is at a high potential and the connection point between the fourth switch tube S4 and the second diode D2 is at a low potential, the voltage input by the input voltage source is a forward voltage, otherwise it is a reverse voltage; For the converter duty cycle T when the input voltage is a positive voltage, the duty cycle of the PWM signal is set to d1 and divided into two time periods 0 to d1T and d1T to T; When the input voltage is a positive voltage, the second switch tube S2 remains in the on state, and a PWM conduction signal with a duty cycle of d1 is applied to the third switch tube S3 and the sixth switch tube S6. A PWM conduction signal with a duty cycle of 1-d1, which is complementary to that of the third switch tube S3 and the sixth switch tube S6, is applied to the fourth switch tube S4 and the fifth switch tube S5. For the converter duty cycle T when the input voltage is a reverse voltage, the duty cycle of the PWM signal is set to d2, which is divided into two time periods: 0 to d2T and d2T to T; When the input voltage is a reverse voltage, the first switch tube S1 remains in the on state, and a PWM conduction signal with a duty cycle of d2 is applied to the fourth switch tube S4 and the fifth switch tube S5. A PWM conduction signal with a duty cycle of 1-d2 complementary to that of the fourth switch tube S4 and the fifth switch tube S5 is applied to the third switch tube S3 and the sixth switch tube S6.

2. The control method of the six-switch matrix converter according to claim 1, characterized in that: When the converter operates from 0 to d1T, the converter is powered by the input AC voltage source V in , the third switch tube S3, the third diode D3, the output filter capacitor C o , the sixth switch tube S6, the sixth diode D6, the inductor L, the second switch tube S2 and the second diode D2 form a loop; When the converter works from d1T to T, the output filter capacitor C o , the fifth switch tube S5, the fifth diode D5, the inductor L, the second switch tube S2, the second diode D2, the fourth switch tube S4 and the fourth diode D4 form a loop; When the converter operates from 0 to d2T, the converter is fed by the input AC voltage source V in , the fourth switch tube S4, the fourth diode D4, the output filter capacitor C o , the fifth switch tube S5, the fifth diode D5, the inductor L, the first switch tube S1 and the first diode D1 form a loop; When the converter works from d2T to T, the output filter capacitor C o , the sixth switch tube S6 , the sixth diode D6 , the inductor L, the first switch tube S1 , the first diode D1 , the third switch tube S3 and the third diode D3 form a loop.

3. The control method of the six-switch matrix converter according to claim 2, characterized in that: When the converter operates from 0 to d1T, the input voltage is positive. The connection point between the first switch S1 and the second switch S2 at both ends of the inductor is set to a high potential, and the connection point between the fifth diode D5 and the sixth diode D6 is set to a low potential. The output voltage is in phase with the input voltage, that is, the connection point between the third diode D3 and the fifth switch S5 is set to a high potential, and the connection point between the fourth diode D4 and the sixth switch S6 is set to a low potential. Then the volt-second product of the inductor L is d1T (V in -V o ), when the converter operates from d1T to T, the volt-second product of the inductor is (1-d1)TV o , then according to the volt-second balance d1T (V in -V o )+(1-d1)TV o =0, then the converter gain M is expressed as: When the converter operates from 0 to d2T, the input voltage is in the reverse direction. The connection point between the first switch S1 and the second switch S2 at both ends of the inductor is still set to a high potential, and the connection point between the fifth diode D5 and the sixth diode D6 is set to a low potential. The output voltage is in phase with the input voltage, that is, the connection point between the third diode D3 and the fifth switch S5 is a low potential, and the connection point between the fourth diode D4 and the sixth switch S6 is a high potential. Then the volt-second product of the inductor L is d2T (V in -V o ), when the converter operates from d2T to T, the volt-second product of the inductor is (1-d2)TV o , then according to the volt-second balance d2T (V in -V o )+(1-d2)TV o =0, then the converter gain M is expressed as:

4. The control method of the six-switch matrix converter according to claim 2, wherein: When a forward voltage is input, the duty cycle d1 is between 0.5 and 1, and the voltage gain M is positive, the output voltage is positive, and is in phase with the input voltage, belonging to the forward voltage in-phase output mode; when the duty cycle d1 is between 0 and 0.5, the voltage gain M is negative, the output voltage is reverse, and is in phase with the input voltage, belonging to the forward voltage inverting output mode; When a reverse voltage is input, when the duty cycle d2 is between 0.5 and 1, the voltage gain M is positive, the output voltage is negative, and is in phase with the input voltage, which belongs to the reverse voltage in-phase output mode. When the duty cycle d1 is between 0 and 0.5, the voltage gain M is negative, the output voltage is negative, and is in phase with the input voltage, which belongs to the reverse voltage inverting output mode.

5. The control method of the six-switch matrix converter according to claim 4, characterized in that: When the converter operates in the same-phase output mode, the duty cycle is in the range of 0.5 to 1 regardless of whether the input voltage is forward or reverse. At this time, the voltage gain M ranges from 1 to positive infinity, achieving different levels of boost. When the converter operates in inverting output mode, the duty cycle is in the range of 0 to 0.5 regardless of whether the input voltage is forward or reverse. At this time, the voltage gain M ranges from negative infinity to 0, achieving different levels of boost and buck.

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