Multi-phase circuit control method and power conversion device

Abstract

The invention provides a multi-phase circuit control method and a power conversion device. The multi-phase circuit control method comprises the following steps of: respectively generating a first control signal and a second control signal to a first phase circuit through a controller; respectively generating a third control signal and a fourth control signal to the second phase circuit through the controller; the two-phase voltage is output to the output end of the power conversion device through the first phase circuit and the second phase circuit; when the controller detects that the output voltage is lower than the first preset voltage, the working period of the third control signal is changed through the controller so as to turn off the primary side circuit of the second phase circuit and the first switch of the rectification side circuit; the working period of the fourth control signal is changed through the controller, so that the primary side circuit of the second phase circuit and the second switch of the rectification side circuit are switched on; and outputting the single-phase voltage to the output end through the first phase circuit and the second phase circuit.

Description

Technical Field

[0001] This case relates to an electronic device and a control method. Specifically, this case relates to a multiphase circuit control method and a power conversion device. Background Art

[0002] The voltage requirements of existing electric vehicles range from 400 volts (V) to 800 volts (V), and the current requirements range from 1 ampere (A) to 40 amperes (A). Based on the situation that the output voltage requires multiple voltage ranges and multiple current ranges, with the design of only a single three-phase resonant circuit in the power conversion device, the gain between the input voltage and the output voltage cannot reach the originally expected gain, or the input voltage and the output voltage cannot reach the expected operating range.

[0003] If directly switching from a three-phase resonant circuit to a two-phase output and a single-phase output, due to different gain requirements for different phases, overshoot and undershoot will occur in the output voltage and output current.

[0004] Therefore, there are still many defects in the above technologies, and it is necessary for practitioners in this field to develop other suitable multiphase circuit control methods and power conversion devices. Summary of the Invention

[0005] One aspect of the present disclosure relates to a multiphase circuit control method. The multiphase circuit control method is applicable to a multiphase circuit. The multiphase circuit is coupled to the input end and the output end of the power conversion device, and is used to convert the input voltage at the input end into the output voltage required at the output end. The multiphase circuit includes a first-phase circuit and a second-phase circuit. Both the first-phase circuit and the second-phase circuit include a primary-side circuit and a rectification-side circuit. Both the primary-side circuit and the rectification-side circuit include a first switch and a second switch. The multiphase circuit control method includes: respectively generating a first control signal and a second control signal to the first-phase circuit through a controller; respectively generating a third control signal and a fourth control signal to the second-phase circuit through the controller; outputting a two-phase voltage to the output end through the first-phase circuit and the second-phase circuit; when the controller detects that the output voltage is lower than a first preset voltage, then changing the working cycle of the third control signal through the controller to turn off the first switch of the primary-side circuit and the rectification-side circuit of the second-phase circuit; changing the working cycle of the fourth control signal through the controller to turn on the second switch of the primary-side circuit and the rectification-side circuit of the second-phase circuit; and outputting a single-phase voltage to the output end through the first-phase circuit and the second-phase circuit.

[0006] Another aspect of the present disclosure relates to a power conversion device. The power conversion device includes a controller and a multiphase circuit. The controller is coupled to the input terminal and the output terminal of the power conversion device, and is configured to generate a first control signal, a second control signal, a third control signal, and a fourth control signal respectively. The multiphase circuit is coupled to the input terminal and the output terminal of the power conversion device. The multiphase circuit includes a first-phase circuit and a second-phase circuit. The multiphase circuit is coupled to the input terminal and the output terminal of the power conversion device. The first-phase circuit is coupled to the controller and is configured to conduct according to the first control signal and the second control signal. The second-phase circuit is coupled to the controller and is configured to conduct according to the third control signal and the fourth control signal. The first-phase circuit and the second-phase circuit jointly generate a two-phase voltage.

[0007] The present disclosure provides a control method, such that the multiphase circuit of the power conversion device can meet different voltage ranges and current ranges, and can respectively provide three-phase voltage, two-phase voltage, and single-phase voltage on the live wire according to the requirements of the output voltage, so as to meet the requirements of different gains. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Referring to the embodiments in the following paragraphs and the following drawings, the content of the present case can be better understood:

[0009] Figure 1 It is a circuit block diagram of a power conversion device shown according to some embodiments of the present case;

[0010] Figure 2 It is a circuit architecture diagram of the controller and the multiphase circuit of the power conversion device shown according to some embodiments of the present case;

[0011] Figure 3 It is a step diagram of a multiphase circuit control method shown according to some embodiments of the present case;

[0012] Figure 4 It is a control signal timing diagram of the multiphase circuit of the power conversion device shown according to some embodiments of the present case;

[0013] Figure 5 It is a circuit state diagram of the multiphase circuit of the power conversion device shown according to some embodiments of the present case;

[0014] Figure 6 It is a schematic diagram of the controller and the multiphase circuit of the power conversion device shown according to some embodiments of the present case;

[0015] Figure 7 It is a control signal timing diagram of the multiphase circuit of the power conversion device shown according to some embodiments of the present case;

[0016] Figure 8Schematic diagram of the circuit state of the multiphase circuit of the power conversion device shown according to some embodiments of the present case; and

[0017] Figure 9 Schematic diagram of the circuit state of the multiphase circuit of the power conversion device shown according to some embodiments of the present case.

[0018] Description of reference numerals

[0019] 100: Power conversion device

[0020] 110: Controller

[0021] 120, 120A, 120B: Multiphase circuit

[0022] 111: Sensing circuit

[0023] 112: Control circuit

[0024] 113: Signal generation circuit

[0025] T1~T12: Switch

[0026] S1~S12: Control signal

[0027] P1~P3: Primary side circuit

[0028] R1~R3: Rectifier side circuit

[0029] Vbus: Bus terminal voltage

[0030] Vo: Output voltage

[0031] Io: Output current

[0032] Cbus, Co: Capacitor

[0033] Cr, Cr1~Cr3: Resonant capacitor

[0034] Lr, Lr1~Lr3: Resonant inductor

[0035] LM, LM1~LM3: Magnetizing inductor

[0036] TS, TS1~TS3: Transformer

[0037] Ls1~Ls3: Rectifier side inductor

[0038] Cs1~Cs3: Capacitor

[0039] H: High level

[0040] L: Low level

[0041] I1~I5: Stage

[0042] I21~I23, I41~I43: Sub - stages Detailed implementation manners

[0043] The spirit of this case will be clearly explained below with the accompanying drawings and detailed descriptions. After any person skilled in the art understands the embodiments of this case, they can make changes and modifications based on the techniques taught in this case, which do not depart from the spirit and scope of this case.

[0044] Figure 1 FIG. is a circuit block diagram of a power conversion device 100 shown according to some embodiments of this case. The power conversion device 100 includes a controller 110 and a multiphase circuit 120.

[0045] In some embodiments, the controller 110 can be implemented by pure hardware and does not rely on software to implement its functions. For example, the controller 110 can monitor the input voltage and output voltage of the multiphase circuit 120 to generate control signals for various switches (not shown in the figure) in the multiphase circuit 120 respectively. In some embodiments where the controller 110 is implemented by pure hardware, the controller 110 can be implemented by an Application Specific Integrated Circuit (ASIC).

[0046] The controller 110 can include, but is not limited to, the integration of a single processor and multiple microprocessors. For example, a Central Processing Unit (CPU), a Digital Signal Processor (DSP), or a Graphic Processing Unit (GPU), etc.

[0047] In some embodiments, under the control of the controller 110, the multiphase circuit 120 can act as a voltage / power converter to convert the input voltage into output voltages of different specifications for driving or powering an electrical load (such as an electric vehicle, a motor, a battery, a processor, etc., not shown in the figure). In some embodiments, the multiphase circuit 120 can be implemented as a Dual Active Bridge (DAB) circuit, a three - phase LLC resonant circuit, or other multiphase conversion circuits with similarities. The multiphase circuit 120 uses multiple phases to provide electrical energy at the output end. By distributing the electrical energy to multiple phases, it can provide higher power output and higher efficiency. The multiphase circuit 120 utilizes its resonant characteristics to make the voltage range of the output voltage larger than that of a general DC / DC conversion circuit and reduce the loss of DC / DC conversion.

[0048] Figure 2 Shown according to some embodiments of this case Figure 1Schematic diagram of the circuit architecture of the controller 110 of the power conversion device 100 and the multiphase circuit 120A. In some embodiments, the multiphase circuit 120A is implemented as a DAB circuit (or a two-phase circuit). The controller 110 and the multiphase circuit 120A are coupled to the input end (i.e., the capacitor Cbus, or the bus bar end) and the output end (i.e., the capacitor Co, or between the live wire and the ground wire of the power grid) of the power conversion device 100.

[0049] In some embodiments, the controller 110 includes a sensing circuit 111, a control circuit 112, and a signal generation circuit 113. The sensing circuit 111 is used to detect the bus bar voltage Vbus at the input end, the output voltage Vo at the output end, and the output current Io, and generate a feedback signal to the control circuit 112. The control circuit 112 is used to generate corresponding instructions according to the feedback signal to control the signal generation circuit 113 to generate corresponding control signals S1-S8 to the multiphase circuit 120A. The signal generation circuit 113 is used to generate control signals S1-S8 to control the multiphase circuit 120A. In some embodiments, the control signals S1-S8 are pulse-width modulation signals (Pulse-width modulation, PWM).

[0050] In some embodiments, the multiphase circuit 120A includes a first-phase circuit, a second-phase circuit, a resonant capacitor Cr, a resonant inductor Lr, an exciting inductor LM, and a transformer TS. The first-phase circuit includes a primary-side circuit P1 and a rectifying-side circuit R1. The second-phase circuit includes a primary-side circuit P2 and a rectifying-side circuit R2. The primary-side circuit P1 and the primary-side circuit P2 are full-bridge circuits. The rectifying-side circuit R1 and the rectifying-side circuit R2 are full-bridge circuits.

[0051] The multiphase circuit 120A is basically composed of four structures, which include a primary side, a resonant side, a transformer side, and a rectifying side. The primary side is the above-mentioned primary-side circuit P1 and primary-side circuit P2. The function of the primary side is to convert the DC voltage (i.e., the bus bar voltage Vbus) into a high-frequency square wave and input it to the resonant side. The resonant side is the resonant tank composed of the above-mentioned resonant capacitor Cr, resonant inductor Lr, and exciting inductor LM. The function of the resonant side is to eliminate the harmonics of the high-frequency square wave on the primary side and output a sine wave.

[0052] Next, the transformer side is the above-mentioned transformer TS. The function of the transformer side is to output the sine wave to the rectifying side and step up or step down according to actual needs. The rectifying side is the rectifying-side circuit R1 and rectifying-side circuit R2. The function of the rectifying side is to convert the sine wave into a stable DC voltage (i.e., the output voltage Vo). The above content is the operation of the multiphase circuit 120A and the output of different multiphase voltages.

[0053] In some embodiments, the primary side circuit P1 includes switches T1 and T2. The primary side circuit P2 includes switches T3 and T4. The rectification side circuit R1 includes switches T5 and T6. The rectification side circuit R2 includes switches T7 and T8. Taking the upper and right sides of the components in the attached drawings as the first ends, switches T1 to T8 all include a first end, a second end, and a control end. The control ends of switches T1 to T8 are alternately turned on in response to the levels of control signals S1 to S8. The second end of switch T1 and the first end of switch T2 are coupled to the second end of the resonant capacitor Cr. The second end of switch T3 and the first end of switch T4 are coupled to the second end of the exciting inductor LM and the fourth end of the transformer TS. The first end of the exciting inductor LM is coupled to the first end of the resonant inductor Lr and the third end of the transformer TS. The second end of the resonant inductor Lr is coupled to the first end of the resonant capacitor Cr. The second end of switch T5 and the first end of switch T6 are coupled to the first end of the transformer TS. The second end of switch T7 and the first end of switch T8 are coupled to the second end of the transformer TS.

[0054] In some examples, switches T1 to T8 can be respectively implemented as P-type Metal-Oxide-Semiconductor Field-Effect Transistors (PMOS) or N-type Metal-Oxide-Semiconductor Field-Effect Transistors (NMOS) according to actual requirements.

[0055] To facilitate the understanding of the operation of the polyphase circuit 120A of this case, please refer to Figure 3 and Figure 4 . Figure 3 It is a schematic diagram of the steps of the polyphase circuit control method 200 according to some embodiments of this case. Figure 4 It is a timing diagram of the control signals of the polyphase circuit 120A of the power conversion device 100 according to some embodiments of this case. Figure 5 It is a schematic diagram of the circuit state of the polyphase circuit 120A of the power conversion device 100 according to some embodiments of this case. The polyphase circuit control method 200 includes steps 210 to 260. The polyphase circuit control method 200 can be executed by Figure 2 the power conversion device 100.

[0056] In step 210, please refer to Figures 2 to 4, the signal generation circuit 113 of the controller 110 generates control signal S1 and control signal S2 to the primary side circuit P1 of the first-phase circuit respectively, and generates control signal S5 and control signal S6 to the rectification side circuit R1 of the first-phase circuit respectively. Control signal S1 is substantially the same as control signal S5. Control signal S2 is substantially the same as control signal S6. Control signal S1 and control signal S2 are reverse signals to each other. The subsequent discussion will focus on control signal S1 and control signal S2. That is to say, the subsequent discussion will focus on the operation of the primary side, and the operation of the rectification side is synchronized with the operation of the primary side, which will not be elaborated in the subsequent paragraphs.

[0057] In step 220, please refer to Figures 2 to 4 , the signal generation circuit 113 of the controller 110 generates control signal S3 and control signal S4 to the primary side circuit P2 of the second-phase circuit respectively, and generates control signal S7 and control signal S8 to the rectification side circuit R2 of the second-phase circuit respectively. Control signal S3 is substantially the same as control signal S7. Control signal S4 is substantially the same as control signal S8. Control signal S3 and control signal S4 are reverse signals to each other. The subsequent discussion will focus on control signal S3 and control signal S4. That is to say, the subsequent discussion will focus on the operation of the primary side, and the operation of the rectification side is synchronized with the operation of the primary side, which will not be elaborated in the subsequent paragraphs.

[0058] In step 230, please refer to Figures 2 to 4 , the switches T1 and T2 of the primary side circuit P1 of the first-phase circuit are turned on alternately according to control signal S1 and control signal S2 respectively in stage I1. At the same time, the switches T3 and T4 of the primary side circuit P2 of the second-phase circuit are turned on alternately according to control signal S3 and control signal S4 respectively. The DC voltage (i.e., the bus terminal voltage Vbus) is converted into a high-frequency square wave through the primary side circuit P1 and the primary side circuit P2. Then, stable two-phase voltages are respectively output to the output terminal (i.e., the capacitor Co) through the conversion of the resonance side, the transformer side and the rectification side. The detailed operation has been described in the above paragraphs and will not be elaborated here. In some embodiments, the range of the two-phase voltage is between 250V and 400V.

[0059] The voltage demand range of existing electric vehicles is between 400 volts (V) and 800 volts (V), and the current demand range is between 1 ampere (A) and 40 amperes (A). Based on the situation that the output voltage requires multiple voltage ranges and multiple current ranges, for example, the voltage and current demands of the original three-phase voltage were 800V and 30 amperes (A) respectively, and now the voltage and current demands of the single-phase voltage are 150V and 10 amperes (A) respectively. With only the design of a single three-phase resonance circuit for the power conversion device, the gain between the input voltage and the output voltage cannot reach the originally expected gain, or the input voltage and the output voltage cannot reach the expected operating range.

[0060] In addition, if directly switching from a three-phase resonant circuit to a two-phase output and a single-phase output, since the gain requirements for different phases are different, overshoot and undershoot will occur in the output voltage and output current. The definition of overshoot means that the signal exceeds the expected value, which is one of the transient responses. Conversely, when the signal is lower than the expected value, it is called undershoot.

[0061] In step 240, please refer to Figures 3 to 5 , when the controller 110 detects that the output voltage Vo is lower than the preset voltage (for example, 250V, the value is only used as an example and is not limited to the embodiments of this case) in stage I1, the controller 110 starts a soft conversion mechanism to switch the output voltage from the stable two-phase voltage to the stable single-phase voltage. The controller 110 changes the duty cycle of the control signal S3 to turn off the switch T3 of the primary side circuit P2 of the second phase circuit and the switch T7 of the rectifier side circuit R2.

[0062] In some embodiments, please refer to Figure 4 and Figure 5 , the controller 110 gradually reduces the duty cycle of the control signal S3 in stage I1 from 50% to 30%, 20%, and 10% in sequence in the three sub-stages I21 to I23 of stage I2. Finally, in stage I3, the controller 110 adjusts the duty cycle of the control signal S3 to zero.

[0063] In step 250, please refer to Figures 3 to 5 , following the description of the above step 240, when the controller 110 detects that the output voltage Vo is lower than the preset voltage (for example, 250V, the value is only used as an example and is not limited to the embodiments of this case) in stage I1, the controller 110 changes the duty cycle of the control signal S4 to fully turn on the switch T4 of the primary side circuit P2 of the second phase circuit and the switch T8 of the rectifier side circuit R2.

[0064] In some embodiments, please refer to Figure 4 and Figure 5 , the controller 110 gradually increases the duty cycle of the control signal S4 in stage I1 from 50% to 70%, 80%, and 90% in sequence in the three sub-stages I21 to I23 of stage I2 (relative to the control signal S3). Finally, in stage I3, the controller 110 adjusts the duty cycle of the control signal S3 to 100%.

[0065] In step 260, please refer to Figures 2 to 4, the switches T1 and T2 of the primary side circuit P1 of the first-phase circuit are maintained to conduct alternately. At the same time, the switch T3 of the primary side circuit P2 of the second-phase circuit is turned off according to the control signal S3, and the switch T4 is turned on according to the control signal S4. A stable single-phase voltage is output to the output terminal (i.e., the capacitor Co) through the first-phase circuit and the second-phase circuit. The detailed operation is similar to that of step 230 and will not be elaborated here.

[0066] In some embodiments, if the output voltage is higher than the preset voltage (for example, 250V, the value is only used as an example and is not limited to the embodiments of this case), the controller 110 changes the working cycle of the control signal S3 and the working cycle of the control signal S4 respectively (equivalent to changing from stage I3 to stage I1 in the reverse direction), so as to switch from outputting a stable single-phase voltage to outputting a stable two-phase voltage through the first-phase circuit and the second-phase circuit. The phase difference between each phase is 180°.

[0067] Through the soft conversion mechanism of the above multi-phase circuit control method 200, the multi-phase circuit 120A can output a two-phase voltage and a single-phase voltage that meet the expected gain respectively, and avoid overshoot and undershoot of the output voltage Vo and the output current Io.

[0068] Figure 6 It is a schematic diagram of the controller 110 and the multi-phase circuit 120B of the power conversion device 100 shown according to some embodiments of this case. In some embodiments, the multi-phase circuit 120B is implemented as a three-phase circuit. The controller 110 and the multi-phase circuit 120B are coupled to the input terminal (i.e., the capacitor Cbus, also called the bus terminal) and the output terminal (i.e., the capacitor Co, also called between the live wire and the ground wire of the power grid) of the power conversion device 100. Figure 6 The internal structure and operation of the controller 110 are basically the same as those of Figure 2 the internal structure of the controller 110, which will not be elaborated here. It should be noted that the design of the original two-phase circuit is increased to a three-phase circuit design, and the controller 110 is used to generate corresponding control signals S1~S12 to the multi-phase circuit 120B. In some embodiments, the control signals S1~S12 are pulse-width modulation signals (Pulse-width modulation, PWM).

[0069] In some embodiments, the multiphase circuit 120B includes a first-phase circuit, a second-phase circuit, a third-phase circuit, resonant capacitors Cr1 to Cr3, resonant inductors Lr1 to Lr3, exciting inductors LM1 to LM3, and transformers TS1 to TS3. The first-phase circuit includes a primary-side circuit P1 and a rectifier-side circuit R1. The second-phase circuit includes a primary-side circuit P2 and a rectifier-side circuit R2. The third-phase circuit includes a primary-side circuit P3 and a rectifier-side circuit R3. The primary-side circuits P1, P2, and P3 are half-bridge circuits. The rectifier-side circuits R1, R2, and R3 are half-bridge circuits.

[0070] Like Figure 2 the multiphase circuit 120A, the multiphase circuit 120B is basically composed of four structures, which include a primary side, a resonant side, a transformer side, and a rectifier side. The primary side is the above-mentioned primary-side circuits P1, P2, and P3, and is used to convert a DC voltage (i.e., the bus terminal voltage Vbus) into a high-frequency square wave for input to the resonant side. The resonant side is the above-mentioned resonant capacitors Cr1 to Cr3, resonant inductors Lr1 to Lr3, and exciting inductors LM1 to LM3, and is used to eliminate the harmonics of the high-frequency square wave on the primary side and output a sine wave.

[0071] The transformer side is the above-mentioned transformers TS1 to TS3, and is used to output the sine wave to the rectifier side and step up or step down according to actual needs. The rectifier side is the rectifier-side circuits R1, R2, and R3, and is used to convert the sine wave into a stable DC voltage (i.e., the output voltage Vo). The above content is the operation of the multiphase circuit 120B and the output of different multiphase voltages.

[0072] In some embodiments, the primary-side circuit P1 includes switches T1 and T2. The primary-side circuit P2 includes switches T3 and T4. The primary-side circuit P3 includes switches T5 and T6. The rectifier-side circuit R1 includes switches T7 and T8. The rectifier-side circuit R2 includes switches T9 and T10. The rectifier-side circuit R3 includes switches T11 and T12.

[0073] In some instances, the switches T1 to T12 can be respectively implemented as P-type Metal-Oxide-Semiconductor Field-Effect Transistors (PMOS) or N-type Metal-Oxide-Semiconductor Field-Effect Transistors (NMOS) according to actual needs.

[0074] Compared with Figure 2The polyphase circuit 120A, the first difference between the polyphase circuit 120B and the polyphase circuit 120A is that there is an additional third-phase circuit. The second difference is that the polyphase circuit 120B has three groups of resonant tanks (i.e., resonant capacitors Cr1 - Cr3, resonant inductors Lr1 - Lr3, and exciting inductors LM1 - LM3), as well as rectifier-side inductors Ls1 - Ls3 and capacitors Cs1 - Cs3. The circuit structure of the polyphase circuit 120B includes three groups of resonant circuits. Each resonant circuit is basically composed of a pair of half-bridge circuits on the primary side and the rectifier side paired with a group of resonant tanks.

[0075] Figure 7 It is a timing diagram of the control signals of the polyphase circuit 120B of the power conversion device 100 shown according to some embodiments of this case. In some embodiments, please refer to Figure 6 and Figure 7 , the switches T1 and T2 of the primary-side circuit P1 of the first-phase circuit are alternately turned on according to the control signal S1 and the control signal S2 respectively in stage I1. At the same time, the switches T3 and T4 of the primary-side circuit P2 of the second-phase circuit are alternately turned on according to the control signal S3 and the control signal S4 respectively. The switches T5 and T6 of the primary-side circuit P3 of the third-phase circuit are alternately turned on according to the control signal S5 and the control signal S6 respectively. The DC voltage (i.e., the bus terminal voltage Vbus) is converted into a high-frequency square wave through the primary-side circuit P1, the primary-side circuit P2, and the primary-side circuit P3. Then, stable three-phase voltages are respectively output to the output terminal (i.e., the capacitor Co) through the conversion of the resonant side, the transformer side, and the rectifier side. In some embodiments, the voltage range of the three-phase voltages is between 400V and 800V or above 800V. The phase difference of each phase of the three-phase voltages is 120°.

[0076] Figure 8 It is a schematic diagram of the circuit state of the polyphase circuit 120B of the power conversion device 100 shown according to some embodiments of this case. In some embodiments, please refer to Figure 7 and Figure 8 , when the controller 110 detects that the output voltage Vo is lower than the preset voltage (for example, 400V, the value is only used as an example and is not limited to the embodiments of this case) in stage I1, then the controller 110 changes the duty cycles of the control signal S5 and the control signal S6 to 30% and 10% respectively in sub-stage I21 and sub-stage I22 of stage I2 in sequence. Finally, in stage I3, the duty cycles of the control signal S5 and the control signal S6 are adjusted to zero by the controller 110 to turn off the primary-side circuit P3 and the rectifier-side circuit R3 of the third-phase circuit.

[0077] Meanwhile, the phase difference between the control signal S1 and the control signal S3 is gradually increased from 120° in the stage I1 to sub-stages I21 and I22 of the stage I2 in sequence by the controller 110. Finally, in the stage I3, the phase difference between the control signal S1 and the control signal S3 is increased to 180°. Similarly, the phase difference between the control signal S2 and the control signal S4 is gradually increased from 120° in the stage I1 to sub-stages I21 and I22 of the stage I2 in sequence by the controller 110. Finally, in the stage I3, the phase difference between the control signal S1 and the control signal S3 is increased to 180°. Finally, the power conversion device 100 outputs a stable two-phase voltage to the output terminal (i.e., the capacitor Co) through the conversion of the primary side, the resonant side, the transformer side, and the rectifier side. The phase difference between each phase of the two-phase voltage is 180°.

[0078] Figure 9 It is a schematic diagram of the circuit state of the multi-phase circuit 120B of the power conversion device 100 shown according to some embodiments of this case. In some embodiments, please refer to Figure 7 and Figure 9 , when the controller 110 detects that the output voltage Vo is further lower than the preset voltage (for example, 250V, the value is only used as an example and is not limited to the embodiments of this case) in the stage I1, then in three sub-stages I41 to I43 of the stage I4 by the controller 110, the duty cycle of the control signal S3 in the stage I3 is gradually reduced from 50% to 30%, 20%, and 10% in sequence. Finally, in the stage I5, the duty cycle of the control signal S3 is adjusted to zero by the controller 110.

[0079] Meanwhile, in three sub-stages I41 to I43 of the stage I4 by the controller 110, the duty cycle of the control signal S4 in the stage I3 is gradually increased from 50% to 70%, 80%, and 90% in sequence (relative to the control signal S3). Finally, in the stage I5, the duty cycle of the control signal S3 is adjusted to 100% by the controller 110.

[0080] Finally, the power conversion device 100 outputs a stable single-phase voltage to the output terminal (i.e., the capacitor Co) through the conversion of the primary side, the resonant side, the transformer side, and the rectifier side.

[0081] In some embodiments, if the output voltage Vo is higher than the preset voltage (for example, 250V, the value is only used as an example and is not limited to the embodiments of this case), then the controller 110 changes the duty cycle of the control signal S3 and the duty cycle of the control signal S4 respectively (equivalent to changing from the stage I5 to the stage I3 in reverse), so as to switch from outputting a stable single-phase voltage to outputting a stable two-phase voltage through the first-phase circuit and the second-phase circuit.

[0082] In some embodiments, if the output voltage Vo is higher than a preset voltage (for example, 400V, the value is only used as an example and is not limited by the embodiments of this case), the controller 110 changes the duty cycle of the control signal S5 and the duty cycle of the control signal S6, and changes the phase of the control signal S3 and the phase of the control signal S4 (equivalent to changing from phase I3 to phase I1 in reverse), so as to switch from the output of a stable two-phase voltage to the output of a stable three-phase voltage through the first-phase circuit, the second-phase circuit, and the third-phase circuit.

[0083] According to the foregoing embodiments, this case provides a design of a multi-phase circuit control method of this case, so that the multi-phase circuit of the power conversion device can meet different voltage ranges and current ranges, and can provide multi-phase voltages (such as three-phase voltage, two-phase voltage, and single-phase voltage) on the live wire according to the requirements of the output voltage to meet the requirements of different gains.

[0084] Although this case is disclosed in detail in the above embodiments, this case does not exclude other feasible implementation manners. Therefore, the protection scope of this case shall be subject to what is defined by the appended claims, rather than being limited by the foregoing embodiments.

Claims

1. A multi-phase circuit control method, applicable to a multi-phase circuit, wherein the multi-phase circuit is coupled to an input terminal and an output terminal of a power conversion device and is used to convert an input voltage of the input terminal into an output voltage required by the output terminal, wherein the multi-phase circuit comprises a first phase circuit and a second phase circuit, wherein the first phase circuit and the second phase circuit both comprise a primary side circuit and a rectifier side circuit, wherein the primary side circuit and the rectifier side circuit both comprise a first switch and a second switch, wherein the multi-phase circuit control method comprises: Generate a first control signal and a second control signal to the first phase circuit respectively by a controller; Generate a third control signal and a fourth control signal to the second phase circuit respectively by the controller; Outputting a two-phase voltage to the output end through the first phase circuit and the second phase circuit; When the controller detects that the output voltage is lower than a first preset voltage, the controller changes the working cycle of the third control signal to turn off the primary side circuit of the second phase circuit and the first switch of the rectifier side circuit; Changing the duty cycle of the fourth control signal by the controller to turn on the primary side circuit of the second phase circuit and the second switch of the rectifier side circuit; as well as A single-phase voltage is output to the output end through the first phase circuit and the second phase circuit.

2. The multi-phase circuit control method according to claim 1, wherein the step of changing the duty cycle of the third control signal by the controller to close the switches of the primary side circuit and the rectifier side circuit of the second phase circuit comprises: gradually reducing the duty cycle of the third control signal by the controller during a switching phase; The step of changing the duty cycle of the fourth control signal by the controller to turn on the primary side circuit and the second switch of the rectifier side circuit of the second phase circuit comprises: The controller gradually increases the duty cycle of the fourth control signal during the switching phase.

3. The multi-phase circuit control method according to claim 1, wherein the multi-phase circuit further comprises a third phase circuit, the third phase circuit comprises an upper arm and a lower arm, wherein the upper arm and the lower arm both comprise a first switch and a second switch, the multi-phase circuit control method further comprises: generating, by the controller, a fifth control signal to the primary side circuit of the third phase circuit and the first switch of the rectifier side circuit; generating a sixth control signal through the controller and the primary side circuit of the third phase circuit and the second switch of the rectifier side circuit; and A three-phase voltage is output to the output end through the first phase circuit, the second phase circuit and the third phase circuit.

4. The multi-phase circuit control method according to claim 3, further comprising: When the controller detects that the output voltage is lower than a second preset voltage, the controller changes the duty cycle of the fifth control signal and the duty cycle of the sixth control signal respectively to close the third phase circuit; Changing the phase of the third control signal and the phase of the fourth control signal by the controller to adjust the driving mode of the second phase circuit; as well as The two-phase voltage is output to the output end through the first phase circuit and the second phase circuit.

5. The multi-phase circuit control method according to claim 4, wherein the step of changing the duty cycle of the fifth control signal and the duty cycle of the sixth control signal by the controller to close the third phase circuit comprises: gradually reducing the duty cycle of the fifth control signal during a switching phase by the controller; and The controller gradually reduces the duty cycle of the sixth control signal during the switching phase.

6. The multi-phase circuit control method according to claim 4, wherein the step of changing the phase of the third control signal and the phase of the fourth control signal by the controller to adjust the driving mode of the second phase circuit comprises: gradually increasing the phase difference between the first control signal and the third control signal by the controller during a switching phase; and The controller gradually increases the phase difference between the second control signal and the fourth control signal during the switching phase.

7. The multi-phase circuit control method according to claim 4, further comprising: When the controller detects that the output voltage is lower than the first preset voltage, the controller changes the duty cycle of the third control signal and the duty cycle of the fourth control signal respectively; and The single-phase voltage is output to the output end through the first phase circuit and the second phase circuit. 8 . The multi-phase circuit control method according to claim 7 , wherein the first preset voltage is lower than the second preset voltage.

9. The multi-phase circuit control method according to claim 7, wherein the step of respectively changing the duty cycle of the third control signal and the duty cycle of the fourth control signal by the controller comprises: gradually reducing the duty cycle of the third control signal during a switching phase by the controller; and The controller gradually increases the duty cycle of the fourth control signal during the switching phase.

10. A power conversion device, comprising: A controller, coupled to the input terminal and the output terminal of the power conversion device, and used to generate a first control signal, a second control signal, a third control signal and a fourth control signal respectively; as well as A multi-phase circuit is coupled to the input terminal and the output terminal of the power conversion device and comprises: A first phase circuit is coupled to the controller and is used to be turned on according to the first control signal and the second control signal; as well as A second phase circuit is coupled to the controller and is used to be turned on according to the third control signal and the fourth control signal, wherein the first phase circuit and the second phase circuit jointly generate a two-phase voltage; When the controller detects that the output voltage of the output end is lower than a first preset voltage, the controller is used to change the duty cycle of the third control signal and the duty cycle of the fourth control signal respectively to control the first phase circuit and the second phase circuit to output a single-phase voltage.

11. The power conversion device according to claim 10, wherein the controller is further configured to generate a fifth control signal and a sixth control signal, wherein the multi-phase circuit further comprises: The third phase circuit is coupled to the controller and is configured to be turned on according to the fifth control signal and the sixth control signal, wherein the third phase circuit, the first phase circuit and the second phase circuit jointly generate a three-phase voltage.

12. The power conversion device according to claim 11, wherein when the controller detects that the output voltage is lower than a second preset voltage, the controller is further used to change the duty cycle of the fifth control signal and the duty cycle of the sixth control signal to shut down the third phase circuit, wherein the control is further used to change the phase of the third control signal and the phase of the fourth control signal to control the first phase circuit and the second phase circuit to output the two-phase voltage. 13 . The power conversion device as claimed in claim 12 , wherein the duty cycle of the fifth control signal and the duty cycle of the sixth control signal are gradually changed to zero during a switching phase.

14. The power conversion device according to claim 12, wherein when the controller detects that the output voltage is lower than the first preset voltage, the controller is further used to change the duty cycle of the third control signal and the duty cycle of the fourth control signal to control the first phase circuit and the second phase circuit to output the single-phase voltage. 15 . The power conversion device as claimed in claim 14 , wherein the duty cycle of the third control signal and the duty cycle of the fourth control signal are gradually changed to be different during a switching phase.

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