MOSFET-based transduction topology and commutation control method for AC power supply

Abstract

The application provides a MOSFET-based conversion topology and an AC power commutation control method, wherein the conversion topology comprises at least four commutation modules connected to the positive and negative poles of the X phase and Y phase of the AC power respectively, the commutation module comprises at least two MOSFETs, one end of a MOSFET is connected to the AC power, the other end of the MOSFET is connected to one end of another MOSFET, the other end of the other MOSFET is an output, and the two MOSFETs are turned on and turned off simultaneously. The conversion topology uses MOSFET devices to perform commutation control on medium-high frequency voltage signals, can realize switching of voltage signals among multiple paths, and has small semiconductor device package, low cost and wide selection range.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a MOSFET-based transducer topology and a commutation control method for AC power supply, which is applied to the design of power electronic transducer circuits. Background Technology

[0002] In terms of voltage signal control, requirements include rapid switching of high-power DC signals, which can be achieved using MOSFETs, gallium nitride transistors, or silicon carbide transistors, with a typical circuit being a half-bridge (full-bridge) drive circuit; rapid switching of low-frequency high-power signals, which can be achieved using thyristors, relays, or switches, with typical circuits being thyristor control circuits or relay control circuits; and rapid switching of medium- and high-frequency high-power signals, which can be achieved using solid-state relays. However, due to their large voltage drop, high heat generation and power consumption during conduction, and the large package size of high-power solid-state relays, which is not conducive to the high integration of printed circuit boards, none of the above circuits can be used stably for long-term rapid switching of medium- and high-frequency high-power signals.

[0003] The content of the background section is merely the technology known to the inventor and does not necessarily represent the prior art in this field. Summary of the Invention

[0004] In view of one or more of the problems existing in the prior art, the present invention provides a MOSFET-based transducer topology and a commutation control method for AC power supply, which can realize reliable and stable switching of AC power supply such as medium and high frequency voltage signals, and the semiconductor devices required for the circuit are small in size, low in cost and have a wide range of options.

[0005] On one hand, the present invention provides a commutation control method for an AC power supply, applied to a MOSFET-based commutation topology. The commutation topology includes a first commutation module, a second commutation module, a third commutation module, and a fourth commutation module. The first terminals of the first and third commutation modules are adapted to be connected to the AC power supply. The second terminals of the first and third commutation modules serve as X-phase output terminals. The first terminals of the second and fourth commutation modules are adapted to be connected to the AC power supply. The second terminals of the second and fourth commutation modules serve as Y-phase output terminals. Each of the first, second, third, and fourth commutation modules includes a bootstrap unit and two back-to-back MOSFETs. The bootstrap unit is adapted to bootstrap the control terminal voltage of the corresponding commutation module to maintain the turn-on voltage of the two MOSFETs at a set value. The method includes:

[0006] The first commutation module, the second commutation module, the third commutation module, and the fourth commutation module are controlled respectively to achieve the following:

[0007] When the first commutation module and the third commutation module are turned on, the second commutation module and the fourth commutation module are turned off;

[0008] When the first commutation module and the third commutation module are turned off, the second commutation module and the fourth commutation module are turned on.

[0009] Specifically, when the first commutation module and the third commutation module are turned on, the bootstrap units of the first commutation module and the third commutation module operate to enable the X-phase output terminal to output the AC power; when the second commutation module and the fourth commutation module are turned on, the bootstrap units of the second commutation module and the fourth commutation module operate to enable the Y-phase output terminal to output the AC power.

[0010] Optionally, the transducer topology further includes a first relay control module and a second relay control module. The first and second relay control modules each include a power resistor. The first relay control module is configured corresponding to the X-phase output terminal, and the second relay control module is configured corresponding to the Y-phase output terminal. The method further includes: when the X-phase output terminal outputs AC power, controlling the first relay control module to turn off and controlling the second relay control module to close, so that the power resistor in the second relay control module is connected between the positive and negative terminals of the Y-phase output terminal to limit the Y-phase output terminal; when the Y-phase output terminal outputs AC power, controlling the first relay control module to close and controlling the second relay control module to open, so that the power resistor in the first relay control module is connected between the positive and negative terminals of the X-phase output terminal to limit the X-phase output terminal.

[0011] Optionally, the MOSFET is an NMOS transistor, wherein the sources of two NMOS transistors arranged back to back are connected and then connected to one end of the bootstrap unit, and the gates of the two NMOS transistors arranged back to back are connected and then connected to the other end of the bootstrap unit.

[0012] Optionally, the bootstrap unit includes a capacitor connected between the gate and source of the two NMOS transistors, and the two ends of the capacitor are adapted to be connected to the control terminal voltage of the corresponding commutation module.

[0013] Optionally, a first transient suppression diode is further connected between the second end of the first commutation module and the second end of the third commutation module, and a second transient suppression diode is further connected between the second end of the second commutation module and the second end of the fourth commutation module.

[0014] On the other hand, embodiments of the present invention also provide a MOSFET-based transduction topology, comprising a first commutation module, a second commutation module, a third commutation module, and a fourth commutation module. The first ends of the first and third commutation modules are adapted to be connected to an AC power supply. The second ends of the first and third commutation modules serve as X-phase output terminals. The first ends of the second and fourth commutation modules are adapted to be connected to the AC power supply. The second ends of the second and fourth commutation modules serve as Y-phase output terminals. The first, second, third, and fourth commutation modules each include a bootstrap unit and two... The MOSFETs are arranged back-to-back. The bootstrap unit is adapted to bootstrap the control terminal voltage of the corresponding commutation module so that the turn-on voltage of the two MOSFETs is always maintained at a set value. When the first commutation module and the third commutation module are turned on, the second commutation module and the fourth commutation module are turned off, and the bootstrap units of the first commutation module and the third commutation module operate so that the X-phase output terminal outputs the AC power. When the first commutation module and the third commutation module are turned off, the second commutation module and the fourth commutation module are turned on, and the bootstrap units of the second commutation module and the fourth commutation module operate so that the Y-phase output terminal outputs the AC power.

[0015] Optionally, the transducer topology further includes a first relay control module and a second relay control module. The first and second relay control modules each include a power resistor. The first relay control module is configured corresponding to the X-phase output terminal, and the second relay control module is configured corresponding to the Y-phase output terminal. When the X-phase output terminal outputs AC power, the first relay control module is turned off, and the second relay control module is closed, so that the power resistor in the second relay control module is connected between the positive and negative terminals of the Y-phase output terminal, thus limiting the Y-phase output terminal. When the Y-phase output terminal outputs AC power, the first relay control module is closed, and the second relay control module is opened, so that the power resistor in the first relay control module is connected between the positive and negative terminals of the X-phase output terminal, thus limiting the X-phase output terminal.

[0016] Optionally, the MOSFET is an NMOS transistor, wherein the sources of two NMOS transistors arranged back to back are connected and then connected to one end of the bootstrap unit, and the gates of the two NMOS transistors arranged back to back are connected and then connected to the other end of the bootstrap unit.

[0017] Optionally, the bootstrap unit includes a capacitor connected between the gate and source of the two NMOS transistors, and the two ends of the capacitor are adapted to be connected to the control terminal voltage of the corresponding commutation module.

[0018] The AC power commutation control method and MOSFET-based commutation topology provided in this invention, through the coordinated control of the first, second, third, and fourth commutation modules, enables the second and fourth commutation modules to be turned off when the first and third commutation modules are on. At this time, the bootstrap units of the first and third commutation modules operate, ensuring that the turn-on voltage of the two MOSFETs in each of these two commutation modules remains at a set value. This keeps the first and third commutation modules always on, achieving a stable and reliable AC power output from the X-phase output terminal. Conversely, when the first and third commutation modules are off, the second and fourth commutation modules are on. Again, the bootstrap units of the second and fourth commutation modules operate, ensuring that the turn-on voltage of the two MOSFETs in each of these two commutation modules remains at a set value. This keeps the second and fourth commutation modules always on, achieving a stable and reliable AC power output from the Y-phase output terminal. Therefore, the AC power commutation control method and MOSFET-based commutation topology of this invention, by using back-to-back MOSFET devices and the bootstrap following effect of the bootstrap unit, ensure that when commutating control of AC power, such as medium- and high-frequency voltage signals, is performed, the AC power output in the X and Y directions can be switched freely, reliably, and stably. Not only is the circuit topology simple and reliable, but it can also control leakage current and ensure that the AC power output can be effectively switched between the X and Y phases. In addition, the semiconductor devices required by the circuit are small in size, low in cost, and have a wide range of options. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of the MOSFET-based transduction topology described in this invention;

[0021] Figure 2 This is a schematic diagram of a preferred embodiment of the MOSFET-based transduction topology of the present invention;

[0022] Figure 3a This is a schematic diagram of the input voltage waveform amplitude;

[0023] Figure 3b This is a schematic diagram of the input voltage waveform frequency;

[0024] Figure 4a This is a schematic diagram of the X-phase voltage output waveform;

[0025] Figure 4b This is a schematic diagram of the Y-phase voltage output waveform;

[0026] Figure 4c This is a schematic diagram of the X-phase voltage output frequency and current peak-to-peak value;

[0027] Figure 4d This is a schematic diagram of the Y-phase voltage output frequency and current peak-to-peak value. Detailed Implementation

[0028] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] The following disclosure provides many different implementations or examples for carrying out different structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed. Preferred embodiments of the invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the invention.

[0031] Figure 1 This is a schematic diagram of the MOSFET-based transducer topology described in this invention, as shown below. Figure 1As shown, the MOSFET-based transducer topology includes four commutation modules H1 to H4 and two relay control modules J1 to J2, wherein:

[0032] Four commutation modules H1 to H4 are connected to the positive and negative terminals of the X and Y phases of the AC signal source, respectively. Each commutation module includes two MOSFETs, with the sources of the two MOSFETs connected together. The drain of one MOSFET is connected to the AC power supply, and the drain of the other MOSFET serves as the AC output. A capacitor is connected between the positive and negative terminals of the external circuit that supplies power to the gates of the two MOSFETs.

[0033] Two relay control modules are respectively connected to the X-phase output terminal and the Y-phase output terminal of the commutation module. Each relay control module includes a relay, and a power resistor is provided between the relay and the X-phase positive output terminal or the Y-phase positive output terminal of the commutation module. The positive enable terminal of the relay is connected to an external voltage through a current-limiting resistor, and the negative enable terminal of the relay is connected to an external voltage through an NMOS transistor.

[0034] like Figure 1 As shown, the four commutation modules are the first commutation module H1, the second commutation module H2, the third commutation module H3, and the fourth commutation module H4, and the two relay control modules are the first relay control module J1 and the second relay control module J2, wherein:

[0035] The first commutation module H1 includes a first field-effect transistor Q1, a second field-effect transistor Q2, and a first capacitor C1. The sources of the first field-effect transistor Q1 and the second field-effect transistor Q2 are connected, and the source voltage is denoted as U1. The drain of the second field-effect transistor Q2 is connected to the positive terminal of the X phase of the AC signal source. The drain of the first field-effect transistor Q1 serves as the output AC-OUT-X+ of the positive terminal of the X phase of the AC signal source. The voltage between the gates of the first field-effect transistor Q1 and the second field-effect transistor Q2 is denoted as U2. The gates are connected to an external circuit. The first capacitor C1 is provided between the voltage DC-X+A obtained by the gate from the positive terminal of the external circuit and the voltage DC-XA obtained by the gate from the negative terminal of the external circuit.

[0036] The third commutation module H3 includes a fifth field-effect transistor Q5, a sixth field-effect transistor Q6, and a third capacitor C3. The sources of the fifth field-effect transistor Q5 and the sixth field-effect transistor Q6 are connected, and the source voltage is denoted as U3. The drain of the sixth field-effect transistor Q6 is connected to the negative terminal of the X phase of the AC signal source. The drain of the fifth field-effect transistor Q5 serves as the output AC-OUT-X- of the negative terminal of the X phase of the AC signal source. The voltage between the gates of the fifth field-effect transistor Q5 and the sixth field-effect transistor Q6 is denoted as U4. The gates are connected to an external circuit. A third capacitor C3 is provided between the voltage DC-X+B obtained by the gate from the positive terminal of the external circuit and the voltage DC-XB obtained by the gate from the negative terminal of the external circuit.

[0037] The second commutation module H2 includes a third field-effect transistor Q3, a fourth field-effect transistor Q4, and a second capacitor C2. The sources of the third field-effect transistor Q3 and the fourth field-effect transistor Q4 are connected. The drain of the third field-effect transistor Q3 is connected to the positive terminal of the Y phase of the AC signal source. The drain of the fourth field-effect transistor Q4 serves as the output AC-OUT-Y+ of the positive terminal of the Y phase of the AC signal source. The gates of the third field-effect transistor Q3 and the fourth field-effect transistor Q4 are connected to an external circuit. The second capacitor C2 is provided between the voltage DC-Y+A obtained by the gate from the positive terminal of the external circuit and the voltage DC-YA obtained by the gate from the negative terminal of the external circuit.

[0038] The fourth commutation module H4 includes a seventh field-effect transistor Q7, an eighth field-effect transistor Q8, and a fourth capacitor C4. The sources of the seventh field-effect transistor Q7 and the eighth field-effect transistor Q8 are connected. The drain of the seventh field-effect transistor Q7 is connected to the negative terminal of the Y phase of the AC signal source. The drain of the eighth field-effect transistor Q8 serves as the output AC-OUT-Y- of the negative terminal of the Y phase of the AC signal source. The gates of the seventh field-effect transistor Q7 and the eighth field-effect transistor Q8 are connected to an external circuit. The fourth capacitor C4 is positioned between the voltage DC-Y+B obtained from the positive terminal of the external circuit and the voltage DC-YB obtained from the negative terminal of the external circuit.

[0039] The first relay control module J1 includes a relay UJ1. The positive and negative terminals of the AC terminal of the relay UJ1 are connected to the output terminal AC-OUT-X+ of the first commutation module Q1 and the output terminal AC-OUT-X- of the third commutation module Q5, respectively. A power resistor R1 is provided at the positive terminal of the AC terminal connected to the first commutation module. The positive terminal of the DC terminal of the relay UJ1 is connected to the external voltage VCC through a current-limiting resistor R2. The positive terminal of the DC terminal of the relay UJ1 is connected to the collector of the first NPN transistor T1. The base of the first NPN transistor T1 is connected to the external voltage ENX through a current-limiting resistor R3.

[0040] The second relay control module J2 includes a relay UJ2. The positive and negative terminals of the AC terminal of relay UJ2 are connected to the output terminals AC-OUT-Y+ of the second commutation module Q4 and AC-OUT-Y- of the fourth commutation module Q8, respectively. A power resistor R5 is installed at the positive terminal of the AC terminal connected to the second commutation module. The positive terminal of the DC terminal of relay UJ2 is connected to the external voltage VCC through a current-limiting resistor R4. The positive terminal of the DC terminal of relay UJ2 is connected to the collector of the second NPN transistor T2. The base of the second NPN transistor T2 is connected to the external voltage ENY through a current-limiting resistor R6.

[0041] Among them, the AC signal source serves as the input terminal of the controlled high-frequency voltage signal. When DC-X+A, DC-XA, DC-X+B, and DC-XB obtain voltages from the external circuit that are not lower than the MOSFET turn-on voltage VGS, the field-effect transistors Q1, Q2, Q5, and Q6 are turned on. The voltage VGS between U1 and U2 and between U3 and U4 is then bootsted to the input voltage. However, the voltage difference between DC-X+A, DC-XA, DC-X+B, and DC-XB will always remain unchanged at VGS, so that the input voltage signal can be output to the AC-OUT-X+ and AC-OUT-X- terminals. At this time, Q3, Q4, Q7, and Q8 are in the off state. The positive half-axis voltage is affected by the off state of Q3 and Q7 and cannot be passed backward. Although the negative half-axis voltage can be turned on backward through the body diodes of Q3 and Q7, it is also affected by the off state of Q4 and Q8 and cannot be passed backward. However, due to the existence of the MOSFET junction capacitance COSS, there is a saturation leakage current IDSS. As the input signal frequency increases, the capacitance impedance decreases and the leakage current increases. Therefore, even if Q3, Q4, Q7, and Q8 remain off, when the positive and negative half-axis voltages alternately operate on the four MOSFETs, there is still leakage current on the MOSFETs output to the AC-OUT-Y+ and AC-OUT-Y- terminals respectively. Therefore, a second relay control module J2 needs to be added to keep ENY at a high level and ENX at a low level, enabling the control relay UJ2. The "dummy load" R5 is connected to the AC-OUT-Y+ and AC-OUT-Y- terminals, so that leakage current flows through R5. The voltage at the AC-OUT-Y+ and AC-OUT-Y- terminals is the same as the voltage across R5. According to Ohm's law U=IR, as long as R is small enough, the voltage at the AC-OUT-Y+ and AC-OUT-Y- terminals can be significantly reduced. This process makes the voltage at the AC-OUT-X+ and AC-OUT-X- approximately equal to the input voltage, while the voltage at the AC-OUT-Y+ and AC-OUT-Y- terminals is greatly limited, approaching the "turn-off" effect. Similarly, if Q3, Q4, Q7, and Q8 are kept on, while Q1, Q2, Q5, and Q6 are off, and ENX is kept high and ENY is kept low, enabling control relay UJ1, the "dummy load" R1 is connected to AC-OUT-X+ and AC-OUT-X-, making the voltage on AC-OUT-Y+ and AC-OUT-Y- approximately equal to the input voltage, while the voltage on AC-OUT-X+ and AC-OUT-X- approaches a "turn-off" effect. This alternating operation achieves alternating voltage energy transfer in both the X and Y directions.

[0042] In addition to employing a similar DC voltage control method, the MOSFET-based transducer topology of this invention incorporates a relay control circuit to control medium- and high-frequency high-power voltage signals. This introduces a "dummy load" and utilizes a reasonable gating method, allowing the input medium- and high-frequency high-power voltage signals to be output alternately at the output terminal. This breaks the traditional notion that MOSFETs cannot control medium- and high-frequency high-power voltage signals.

[0043] Figure 2 This is a schematic diagram of a preferred embodiment of the MOSFET-based transducer topology described in this invention, as shown below. Figure 2 As shown, the MOSFET-based transducer topology includes four commutation modules H1 to H4 and two relay control modules J1 and J2. The positive output terminals of the first commutation module H1 and the second commutation module H2 are equipped with fuses F1 and F2. The positive output terminal AC-OUT-X+ of the first commutation module H1 and the negative output terminal AC-OUT-X- of the third commutation module H3 are equipped with a parallel load power resistor R7 and a transient suppression diode D1. The positive output terminal of the second commutation module H2 and the negative output terminal of the fourth commutation module H4 are equipped with a parallel load power resistor R8 and a transient suppression diode D2. Figure 3a and 3b As shown, a 130V, 200kHz AC signal enters from the AC signal source. Within 900ms, DC-X+A, DC-XA, DC-X+B, and DC-XB are externally input with a 5V voltage, while DC-Y+A, DC-YA, DC-Y+B, and DC-YB remain floating. An external 3.3V high-level input to the ENY terminal closes T2, connecting R5 to the AC-OUT-Y+ and AC-OUT-Y- terminals. At this time, the oscilloscope probes are clamped to the AC-OUT-X+ and AC-OUT-X- terminals, providing an approximate input AC signal. Furthermore, the current on the load R7 can be monitored using a current probe, which shows approximately 1.3A. Meanwhile, the voltages at the AC-OUT-Y+ and AC-OUT-Y- terminals are "turned off." Similarly, in the next 900ms cycle, DC-Y+A, DC-YA, DC-Y+B, and DC-YB are externally input with a 5V voltage, while DC-X+A, DC-XA, DC-X+B, and DC-XB remain floating. An external 3.3V high-level input to the ENX terminal closes T1, thus "turning on" the voltages at AC-OUT-Y+ and AC-OUT-Y- terminals and "turning off" the voltages at AC-OUT-X+ and AC-OUT-X- terminals. The current across the load R8 is also approximately 1.3A. For example... Figures 4a-4dAs shown, the X-phase and Y-phase output voltages are complementary and alternate with a transduction period of 900ms, while the amplitude and frequency remain essentially constant. With an input peak-to-peak voltage of 130V and a frequency of 200kHz (medium-high frequency), this circuit can realize the alternating transduction of X-phase and Y-phase voltages. Furthermore, when a high-power load is applied to the output, the current output capability can reach approximately 1.3A, and it can operate stably for extended periods. Figures 3a to 4d This is the result of saving waveforms obtained from tests using an oscilloscope (Tektronix DPO2012B). Different horizontal and vertical scales are set according to different test requirements, without affecting the signal itself and facilitating signal observation and study. For example, Figure 3a In the middle, the horizontal scale is 200ms / div, and the vertical scale of the 1-channel is 50V / div; Figure 3b In the middle, the horizontal scale is 2µs / div, and the vertical scale of the 1-channel module is 50V / div; Figure 4a In the middle, the horizontal scale is 400ms / div, and the vertical scale of the 1-channel is 50V / div; Figure 4b In the middle, the horizontal scale is 400ms / div, and the vertical scale is 50V / div; Figure 4c In the middle, the horizontal scale is 2us / div, the 1st channel vertical scale is 50V / div, and the 2nd channel vertical scale is 500mA / div; Figure 4d In the middle, the horizontal scale is 2us / div, the vertical scale of channel 1 is 50V / div, and the vertical scale of channel 2 is 500mA / div.

[0044] In a specific embodiment of the present invention, F1 and F2 are UN2410-1300FS fast-blow fuses with a rated current of 3A and a maximum voltage of 250V, which are used to protect the circuit output voltage and current from exceeding the design limits; R7 and R8 are load power resistors, which are 100Ohm 150W aluminum-cased power resistors, which are used as loads to test the circuit's load-carrying capacity; D1 and D2 are SMBJ400CA avalanche diodes with a reverse turn-off voltage of 400V, which are used to improve the circuit's electrostatic discharge protection level; Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are N-channel MOSFETs, specifically BSC320N20NS3G, with a source-drain VDS of 200V, a current withstand capability of 36A, a maximum output junction capacitance COSS of 180pF, and a maximum leakage current IDSS of 1nA at room temperature (conditions: VDS=160V, VGS=0). As can be seen from the basic schematic diagram of MOSFET, there are junction capacitances between the gate, source, and drain of MOSFET, namely CGD, CGS, and CDS, respectively. When the MOSFET is turned off, VGS=0, and the gate and source can be regarded as a short circuit. Therefore, the output junction capacitance of MOSFET is CGD+CDS, i.e., COSS. From the capacitance impedance XC=1 / jɷC, it can be seen that under a certain frequency, the smaller the capacitance, the greater the impedance. Therefore, if the COSS value of the selected MOSFET is smaller, its "turn-off" effect is better, and this value is positively correlated with the leakage current IDSS. C1, C2, C3, and C4 are ceramic capacitors, specifically GRM219B31H225KE15D, Murata 2.2uF, 50V, 0805 package surface mount capacitors. Their function is to act as bootstrap capacitors to raise the voltage, keeping the voltage difference at the control terminal always at 5V. UJ1 and UJ2 are G3VM-201G1, MOSFET relays, with a load voltage VOFF of 200V peak voltage and a continuous current IO of 200mA. Their function is to periodically connect the "false" relay. R1 and R5 are surface-mount power resistors, 25121WF510JT4E, 51 Ohm, 1W power surface-mount resistors, serving as "dummy loads" for the circuit; R2 and R4 are current-limiting resistors, 0603WAF1001T5E, serving as current-limiting resistors for the MOSFET control terminals, with a forward current IF below 25mA. Preferably, R2 and R4 are 1KOhm, 1 / 8W surface-mount resistors, with a forward current IF of 5mA; T1 and T2 are SS8050, NPN transistors, used to facilitate MCU driving of the MOSFET control terminals ENX and ENY; R3 and R6 are current-limiting resistors, 0603WAF1001T5E, 1KOhm, 1 / 10W surface-mount resistors, used to prevent excessive base current of the SS8050.

[0045] The MOSFET-based transducer topology described in this invention uses a simple and efficient combination of field-effect transistors and resistor-capacitor components to control the commutation of medium- to high-frequency voltage signals. It has strong current output capability and can operate stably for a long time.

[0046] The above provides an embodiment including four commutation modules and two relay control modules. However, the present invention is not limited thereto. Each phase of the AC signal source can include multiple commutation modules, or a multi-channel relay control module, or multiple relay control modules. Other switching control modules connected to the output of the commutation modules can also be used. That is, the MOSFET-based transducer topology of the present invention can include at least four commutation modules, respectively connected to the positive and negative terminals of the X and Y phases of the AC power supply. Each commutation module includes at least two MOSFETs. One end of one MOSFET is connected to the AC power supply, and the other end is connected to one end of another MOSFET. The other end of the other MOSFET is the output. Both MOSFETs are simultaneously turned on and off. The MOSFET-based transducer topology of the present invention can also include one or more relay control modules to reduce the leakage current of the non-conducting commutation modules. Each relay control module includes a relay and a power resistor. The power resistor is connected between the output terminal of the non-conducting commutation module and the relay, and the leakage current is controlled by the resistance value of the power resistor.

[0047] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A commutation control method for an AC power supply, characterized in that, An application is made to a MOSFET-based transducer topology, the topology comprising a first commutation module, a second commutation module, a third commutation module, and a fourth commutation module. The first terminals of the first and third commutation modules are adapted to be connected to an AC power supply. The second terminals of the first and third commutation modules serve as X-phase output terminals. The first terminals of the second and fourth commutation modules are adapted to be connected to the AC power supply. The second terminals of the second and fourth commutation modules serve as Y-phase output terminals. Each of the first, second, third, and fourth commutation modules includes a bootstrap unit and two back-to-back MOSFETs. The bootstrap unit is adapted to bootstrap the control terminal voltage of the corresponding commutation module to maintain the turn-on voltage of the two MOSFETs at a set value. The method includes: The first commutation module, the second commutation module, the third commutation module, and the fourth commutation module are controlled respectively to achieve the following: When the first commutation module and the third commutation module are turned on, the second commutation module and the fourth commutation module are turned off; When the first commutation module and the third commutation module are turned off, the second commutation module and the fourth commutation module are turned on. Specifically, when the first commutation module and the third commutation module are turned on, the bootstrap units of the first commutation module and the third commutation module operate to enable the X-phase output terminal to output the AC power; when the second commutation module and the fourth commutation module are turned on, the bootstrap units of the second commutation module and the fourth commutation module operate to enable the Y-phase output terminal to output the AC power.

2. The AC power supply commutation control method according to claim 1, characterized in that, The transducer topology further includes a first relay control module and a second relay control module, each including a power resistor. The first relay control module is configured corresponding to the X-phase output terminal, and the second relay control module is configured corresponding to the Y-phase output terminal. The method further includes: When the AC power is output from the X-phase output terminal, the first relay control module is turned off and the second relay control module is turned off, so that the power resistor in the second relay control module is connected between the positive and negative terminals of the Y-phase output terminal to limit the Y-phase output terminal. When the AC power is output from the Y-phase output terminal, the first relay control module is closed and the second relay control module is opened, so that the power resistor in the first relay control module is connected between the positive and negative terminals of the X-phase output terminal to limit the X-phase output terminal.

3. The AC power supply commutation control method according to claim 1 or 2, characterized in that, The MOSFET is an NMOS transistor, wherein the sources of two NMOS transistors arranged back to back are connected and then connected to one end of the bootstrap unit, and the gates of the two NMOS transistors arranged back to back are connected and then connected to the other end of the bootstrap unit.

4. The AC power supply commutation control method according to claim 3, characterized in that, The bootstrap unit includes a capacitor connected between the gate and source of the two NMOS transistors, and the two ends of the capacitor are adapted to be connected to the control terminal voltage of the corresponding commutation module.

5. The AC power supply commutation control method according to claim 1 or 2, characterized in that, A first transient suppression diode is connected between the second end of the first commutation module and the second end of the third commutation module, and a second transient suppression diode is connected between the second end of the second commutation module and the second end of the fourth commutation module.

6. A MOSFET-based transduction topology, characterized in that, The system includes a first commutation module, a second commutation module, a third commutation module, and a fourth commutation module. The first terminals of the first and third commutation modules are adapted to be connected to an AC power supply. The second terminals of the first and third commutation modules serve as X-phase output terminals. The first terminals of the second and fourth commutation modules are adapted to be connected to the AC power supply. The second terminals of the second and fourth commutation modules serve as Y-phase output terminals. Each of the first, second, third, and fourth commutation modules includes a bootstrap unit and two back-to-back MOSFETs. The bootstrap unit is adapted to bootstrap the control terminal voltage of the corresponding commutation module to maintain the turn-on voltage of the two MOSFETs at a set value. When the first commutation module and the third commutation module are turned on, the second commutation module and the fourth commutation module are turned off, and the bootstrap units of the first commutation module and the third commutation module are activated so that the X-phase output terminal outputs the AC power supply. When the first commutation module and the third commutation module are turned off, the second commutation module and the fourth commutation module are turned on, and the bootstrap units of the second commutation module and the fourth commutation module are activated so that the Y-phase output terminal outputs the AC power.

7. The transducer topology according to claim 6, characterized in that, The transducer topology further includes a first relay control module and a second relay control module. Each of the first and second relay control modules includes a power resistor. The first relay control module is configured corresponding to the X-phase output terminal, and the second relay control module is configured corresponding to the Y-phase output terminal. When the AC power is output from the X-phase output terminal, the first relay control module is turned off and the second relay control module is closed, so that the power resistor in the second relay control module is connected between the positive and negative terminals of the Y-phase output terminal to limit the Y-phase output terminal. When the AC power is output from the Y-phase output terminal, the first relay control module is closed and the second relay control module is open, so that the power resistor in the first relay control module is connected between the positive and negative terminals of the X-phase output terminal to limit the X-phase output terminal.

8. The transducer topology according to any one of claims 6-7, characterized in that, The MOSFET is an NMOS transistor, wherein the sources of two NMOS transistors arranged back to back are connected and then connected to one end of the bootstrap unit, and the gates of the two NMOS transistors arranged back to back are connected and then connected to the other end of the bootstrap unit.

9. The transducer topology according to claim 8, characterized in that, The bootstrap unit includes a capacitor connected between the gate and source of the two NMOS transistors, and the two ends of the capacitor are adapted to be connected to the control terminal voltage of the corresponding commutation module.

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