Multi-phase power converter and control method thereof

Abstract

A multi-phase power converter comprises at least two-phase power conversion circuits and a control signal generation unit. Each power conversion circuit comprises a switch bridge arm formed by an upper switch and a lower switch which are connected in series. The control signal generating unit obtains the load state of the multi-phase power converter according to the received output current of the multi-phase power converter and provides control signals for the upper switches and the lower switches. When the load state is a light load state, the control signal generating unit correspondingly turns on or off the upper switch and the lower switch, so that the at least two phases of switch bridge arms are driven alternately. The invention further relates to a control method of the multi-phase power converter.

Description

Technical Field

[0001] The present invention relates to a multi-phase power converter and a control method thereof, and more particularly to a multi-phase power converter in which at least two-phase switch bridge arms are alternately driven and a control method thereof. Background Art

[0002] In recent years, with the rapid development of the information industry, power supplies have become an indispensable key role. As the power demand of large-scale information equipment gradually increases, the output power of power supplies has also gradually increased due to the increase in load demand.

[0003] When the power of a single power supply is sufficient, the AC / DC converter of the previous stage usually adopts a single power factor correction (PFC) architecture. However, when the overall power of the system increases, the disadvantages will become apparent because more parallel power supplies are required to meet the demand. When using the N-phase architecture, in order to obtain higher efficiency, when the load is light, only one phase will operate, and it will not be fully started until the load gradually increases to a certain level.

[0004] In the AC / DC converter, the circuit architecture with upper and lower arm switches is used. If the upper and lower fast arm drive circuits use independent power supplies, under light load, other phases will be turned off, and the upper arm drive power will remain greater than the UVLO (Undervoltage-Lockout) state of the driver IC. This design is suitable for use when the power supply is supplied with a heavier load instantly from no load or light load. Figure 1 As shown, a two-phase power conversion architecture is taken as an example, that is, the multi-phase power converter includes a first power conversion circuit 91 and a second power conversion circuit 92. When the upper and lower fast arm drive circuits use independent power supplies, the total input current I IN , the first input current I flowing into the first power conversion circuit 91 IN1 The second input current I IN2 Can be as Figure 2 As shown, it is a schematic diagram of the current waveform of the upper and lower arm driving circuits of the existing power supply as independent power supplies. For the first power conversion circuit 91 and the second power conversion circuit 92, which are independently controlled, Figure 2The current waveform diagram shown in the figure shows that under light load (i.e. before time t1), the first power conversion circuit 91 operates (drives), while the second power conversion circuit 92 is in an idle state; when the power supply instantly provides a heavier load from no load or light load (i.e. after time t1), since the driver IC power supply Vcc is greater than the UVLO voltage, the second power conversion circuit 92 does not need to go through the startup time (charging the upper arm), and the upper and lower arm switches can work normally immediately, and there will be no instantaneous large current stress. However, the use of independent power supply will increase the circuit size and cost.

[0005] If the upper and lower fast arm drive circuits are supplied by a single power supply, a diode is usually added to the upper arm power supply Vcc. When the lower arm is turned on, the diode charges the upper arm capacitor in the forward direction. If the upper arm capacitor voltage is lower than the UVLO voltage of the driver IC, the upper arm drive signal will be forced to turn off. Under light load conditions, only one phase is used to improve efficiency, and the other phases are forced to standby. However, when the load suddenly increases, all phases must be turned on, including the phases that were originally forced to standby. However, since their upper arm capacitors may be lower than the UVLO voltage of the driver IC, their upper arm drive signals will be forced to turn off, and may not be able to provide sufficient energy, resulting in a decrease in output voltage. Figure 3 As shown in FIG. 1 , it is a schematic diagram of the current waveform of the upper and lower arm drive circuits of the existing power supply being supplied by a single power supply. Although the voltage of the upper arm drive signal Vcc can be maintained by turning on the lower arm switch during standby to prevent it from being lower than the UVLO voltage, it will also have the side effect of affecting the total harmonic distortion of the current. Since the lower arm must be forced to turn on, the total input current I IN A second input current I must be provided IN2 However, due to the second input current I IN2 The role of the upper arm drive signal Vcc is only to maintain the voltage of the upper arm drive signal. Therefore, the burst mode is generally used to allow the upper arm drive power supply to have enough drive signal Vcc voltage by turning on for a short period of time. However, the total input current I IN The quality of the current decreases.

[0006] Therefore, how to design a multi-phase power converter and a control method thereof to solve the problems and technical bottlenecks existing in the prior art is an important topic studied by the inventors of the present disclosure. Summary of the invention

[0007] One object of the present invention is to provide a multi-phase power converter. The multi-phase power converter provides an operation of converting input power into output power. The multi-phase power converter includes at least two-phase power conversion circuits and a control signal generating unit. Each power conversion circuit includes a switch bridge arm formed by an upper switch and a lower switch connected in series. The control signal generating unit obtains the load state of the multi-phase power converter based on the output current received by the multi-phase power converter, and provides control signals for each upper switch and each lower switch. When the load state is a light load state, the control signal generating unit turns on or off the upper switch and the lower switch accordingly, so that at least two-phase switch bridge arms are driven alternately.

[0008] Another object of the present invention is to provide a control method for a multi-phase power converter. The multi-phase power converter includes at least two-phase power conversion circuits, each of which includes a switch bridge arm formed by an upper switch and a lower switch connected in series. The control method includes: judging the load state of the multi-phase power converter according to the output current of the multi-phase power converter; and when the load state is a light load state, controlling at least two-phase switch bridge arms to be driven alternately.

[0009] Thus, the multi-phase power converter and the multi-phase power converter control method proposed in the present invention have the following features and advantages: 1. The driving circuit of the multi-phase power converter of the present invention adopts a single power supply, which is conducive to the design of miniaturization of the circuit volume and reduces the cost; 2. The total input current I IN The total harmonic distortion is greatly reduced, which improves the current quality. 3. The multi-phase switch bridge arms are driven alternately, and each has an average conduction time, so the power loss is also averaged. In addition, the temperature of the switch crystal is also more average. In addition to facilitating the design of heat dissipation and cooling, it is not easy to cause the problem of large differences in life due to imbalance in usage time.

[0010] In order to further understand the technology, means and technical effects adopted by the present invention to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, characteristics and features of the present invention can be deeply and specifically understood thereby. However, the drawings are only provided for reference and explanation and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 :A circuit block diagram of an existing multi-phase power conversion architecture.

[0012] Figure 2 : A schematic diagram of current waveforms of the upper and lower arm drive circuits of the existing power supply being independent power supplies.

[0013] Figure 3 : A schematic diagram of current waveforms of the upper and lower arm driving circuits of a conventional power supply when they are supplied by a single power source.

[0014] Figure 4 : is a block diagram of the architecture of the multi-phase power converter of the present invention.

[0015] Figure 5 : is a circuit diagram of a multi-phase power converter of the present invention having a two-phase switch bridge arm.

[0016] Figure 6 : is a circuit diagram of a multi-phase power converter of the present invention having a three-phase switch bridge arm.

[0017] Figure 7 : is a circuit diagram of a multi-phase power converter of the present invention having a totem pole power factor correction circuit.

[0018] Figure 8 : is a schematic diagram of current waveforms of the multi-phase switch bridge arms of the multi-phase power converter of the present invention being alternately driven.

[0019] Fig. 9 : is a flow chart of the control method of the multi-phase power converter of the present invention.

[0020] Description of reference numerals:

[0021] 100: Multiphase Power Converter

[0022] 11~1N: Power conversion circuit

[0023] V IN : Input power

[0024] V OUT : Output power

[0025] V AC : AC power supply

[0026] I OUT : Output current

[0027] 21~23: Power conversion circuit

[0028] Q H1 ,Q H2 ,Q H3 : On switch

[0029] Q L1 ,Q L2 ,Q L3 :Down switch

[0030] Q A ,Q B : Slow up and down switch

[0031] L1, L2, L3: Inductor

[0032] C OUT : Output capacitor

[0033] S H1 ,S L1 ,S H2 ,S L2 ,S H3 ,S L3 ,S A ,S B : Switch control signal 311: First upper drive circuit

[0034] 312: First lower driving circuit

[0035] 321: Second upper drive circuit

[0036] 322: Second lower driving circuit

[0037] 41: The first bootstrap circuit

[0038] 42: Second bootstrap circuit

[0039] D b1 ,D b2 :diode

[0040] C b1 ,C b2 ;capacitance

[0041] R b1 ,R b2 :Current limiting resistor

[0042] 91: First power conversion circuit

[0043] 92: Second power conversion circuit

[0044] I IN : Total input current

[0045] I IN1 : First input current

[0046] I IN2 : Second input current

[0047] S10, S20: Steps DETAILED DESCRIPTION

[0048] The technical content and detailed description of the present invention are described as follows with reference to the accompanying drawings.

[0049] See also Figure 4 As shown in FIG. 1 , it is a block diagram of the architecture of the multi-phase power converter of the present invention. The multi-phase power converter (N-phase, multi-phase) 100 is used as the input power source V IN Converted to output power V OUT operation, where the input power V INIt can be an AC power supply or a DC power supply, and the output power V OUT It can be an AC power source or a DC power source, that is, the multi-phase power converter 100 can be used for AC-DC conversion, DC-AC conversion, and DC-DC conversion.

[0050] The multi-phase power converter 100 includes at least two-phase power conversion circuits 11-1N, and each phase power conversion circuit 11-1N is connected in parallel to each other to meet the increasing power demand of large-scale information equipment for high output power applications. Figure 5 or Figure 6 As shown, each power conversion circuit 11-1N (i.e., power conversion circuits 21, 22, 23) includes an upper switch Q connected in series. H1 ,Q H2 ,Q H3 With the next switch Q L1 ,Q L2 ,Q L3 The switch bridge arm formed. Figure 5 A circuit diagram of a multi-phase power converter of the present invention having two-phase switch bridge arms; Figure 6 The circuit diagram of the multi-phase power converter of the present invention has a three-phase switch bridge arm.

[0051] exist Figure 5 In the embodiment shown, the multi-phase power converter 100 is used for AC-DC conversion, that is, for power factor correction (PFC). The multi-phase power converter 100 includes two-phase power conversion circuits 21, 22, that is, two-phase switch bridge arms 21, 22, namely, a first switch bridge arm 21 and a second switch bridge arm 22. The first switch bridge arm 21 includes a first upper switch Q H1 The first lower switch Q in series L1 The second switch bridge arm 22 includes a second upper switch Q H2 The second lower switch Q in series L2 .

[0052] Compared to Figure 5 In the embodiment shown, Figure 6 In the embodiment shown, the multi-phase power converter 100 is also used as a power factor corrector (PFC), and the multi-phase power converter 100 includes a three-phase power conversion circuit 21, 22, 23, that is, a three-phase switch bridge arm 21, 22, 23, namely a first switch bridge arm 21, a second switch bridge arm 22 and a third switch bridge arm 23. The first switch bridge arm 21 includes a first upper switch Q H1 The first lower switch Q in series L1 The second switch bridge arm 22 includes a second upper switch Q H2 The second lower switch Q in series L2 The third switch bridge arm 23 includes a third upper switch QH3 The third lower switch Q in series L3 .

[0053] exist Figure 6 In the power factor corrector application, the first switch bridge arm 21, the second switch bridge arm 22 and the third switch bridge arm 23 are used as fast switch bridge arms, so the circuit architecture also includes a slow switch bridge arm, which includes a slow upper switch Q A With the slow down switch Q in series B . Figure 5 The same is true, so I won’t go into details.

[0054] Furthermore, the multi-phase power converter 100 includes a control signal generating unit, wherein the control signal generating unit is not limited to a specific form, and any controller, control circuit, etc. that can be used to generate a signal for controlling the upper and lower switches of the aforementioned switch bridge arm should be included in the scope of the present invention. The control signal generating unit generates a control signal according to the received output current I OUT , obtain the load state (i.e., light load, heavy load state) of the multi-phase power converter 100, and provide each upper switch Q H1 ,Q H2 ,Q H3 With each lower switch Q L1 ,Q L2 ,Q L3 control signal.

[0055] like Figure 5 and Figure 6 As shown, the control signal generating unit provides a first upper switch control signal S H1 , the first switch control signal S L1 respectively control the first upper switch Q of the first switch bridge arm 21 H1 With the first switch Q L1 ; Provide a second upper switch control signal S H2 , the second switch control signal S L2 respectively control the second upper switch Q of the second switch bridge arm 22 H2 With the second lower switch Q L2 Furthermore, if Figure 6 As shown, the control signal generating unit further provides a third upper switch control signal S H3 , the third switch control signal S L3 respectively control the third upper switch Q of the third switch bridge arm 23 H3 With the third lower switch Q L3 .

[0056] Therefore, the control signal generating unit is based on the load state (based on the output current I OUT ) is in a light load state, the upper switches Q are turned on or off accordingly.H1 ,Q H2 ,Q H3 With the lower switch Q L1 ,Q L2 ,Q L3 , so that the at least two-phase switch bridge arms are driven alternately. With input power V IN Take AC power supply as an example (such as Figure 5 and Figure 6 The AC power supply V AC ), at least two-phase switch bridge arms are based on the AC power supply V AC By the way, if the control signal generating unit is in a heavy load state according to the load state, the upper switches Q are turned on or off accordingly. H1 ,Q H2 ,Q H3 With the lower switch Q L1 ,Q L2 ,Q L3 , so that the at least two-phase switch bridge arms are driven simultaneously.

[0057] like Figure 5 The multi-phase power converter shown in the figure has two-phase switch bridge arms. The first switch bridge arm 21 and the second switch bridge arm 22 can be respectively connected to the AC power source V AC (That is, the input power V IN ) is driven alternately when the positive and negative half cycles are exchanged. That is, when the AC power supply V AC When it is a positive half cycle, the first upper switch control signal S provided by the control signal generating unit H1 With the first lower switch control signal S L1 respectively control the first upper switch Q of the first switch bridge arm 21 H1 With the first switch Q L1 At this time, only one phase, namely the first switch bridge arm 21, is in operation, which means that the second switch bridge arm 22 is in an idle state.

[0058] When the AC power supply V AC When it is a negative half cycle, the second upper switch control signal S provided by the control signal generating unit H2 and the second lower switch control signal S L2 respectively control the second upper switch Q of the second switch bridge arm 22 H2 With the second lower switch Q L2 At this time, only one phase, namely the second switch bridge arm 22, is in operation, which means that the first switch bridge arm 21 is in an idle state.

[0059] However, the first switch bridge arm 21 and the second switch bridge arm 22 operate in the positive and negative half cycles respectively, which is not intended to limit the present invention. That is, when the AC power source V ACWhen the AC power source V AC During the negative half cycle, the first switch bridge arm 21 can also be controlled to operate (the second switch bridge arm 22 is idle). Although the first switch bridge arm 21 and the second switch bridge arm 22 operate in different half cycles, the same technical effect can still be achieved.

[0060] Therefore, for Figure 5 As for the two-phase switch bridge arms shown, since the two-phase switch bridge arms are driven alternately and each has a 50% conduction time, the power loss is also 50% each. In addition, the temperature of the switch crystal is more uniform. In addition to facilitating the design of heat dissipation and cooling, it is not easy to cause the problem of large differences in life due to unbalanced usage time.

[0061] like Figure 6 The multi-phase power converter shown in the figure has three-phase switch bridge arms. The first switch bridge arm 21, the second switch bridge arm 22 and the third switch bridge arm 23 can be respectively connected to the AC power source V AC (That is, the input power V IN ) are driven alternately at intervals of 120 electrical degrees. For example, but not limiting the present invention, when the AC power source V AC When the first upper switch control signal S provided by the control signal generating unit is 0 degrees, H1 With the first lower switch control signal S L1 respectively control the first upper switch Q of the first switch bridge arm 21 H1 With the first switch Q L1 At this time, only one phase, namely the first switch bridge arm 21, is in operation, which means that the second switch bridge arm 22 and the third switch bridge arm 23 are in an idle state.

[0062] When the AC power supply V AC When the second upper switch control signal S provided by the control signal generating unit is 120 degrees, H2 and the second lower switch control signal S L2 respectively control the second upper switch Q of the second switch bridge arm 22 H2 With the second lower switch Q L2 At this time, only one phase, namely the second switch bridge arm 22, is in operation, which means that the first switch bridge arm 21 and the third switch bridge arm 23 are in an idle state.

[0063] When the AC power supply V AC When the third upper switch control signal S provided by the control signal generating unit is 240 degrees, H3 and the third lower switch control signal S L3 respectively control the third upper switch Q of the third switch bridge arm 23 H3With the third lower switch Q L3 At this time, only one phase, namely the third switch bridge arm 23, is in operation, which means that the first switch bridge arm 21 and the second switch bridge arm 22 are in an idle state.

[0064] However, the above-mentioned operation of the first switch bridge arm 21, the second switch bridge arm 22 and the third switch bridge arm 23 in sequence at intervals of 120 electrical degrees is not intended to limit the present invention, that is, after the first switch bridge arm 21 operates (the second switch bridge arm 22 and the third switch bridge arm 23 are idle), the third switch bridge arm 23 may be switched to operate (the first switch bridge arm 21 and the second switch bridge arm 22 are idle), and then the second switch bridge arm 22 may be switched to operate (the first switch bridge arm 21 and the third switch bridge arm 23 are idle). Although the operation order of the first switch bridge arm 21, the second switch bridge arm 22 and the third switch bridge arm 23 is different, the same technical effect can still be achieved.

[0065] Therefore, it can be seen from the above description that when the multi-phase power converter has N-phase switch bridge arms, the N-phase switch bridge arms are respectively connected to the AC power source V AC The electrical angle is 360 / N degrees and they are driven alternately.

[0066] See also Figure 7 , which is a circuit diagram of a multi-phase power converter of the present invention having a totem pole power factor correction circuit. The totem pole power factor correction circuit includes a first switch bridge arm 21, a second switch bridge arm 22, a first upper drive circuit 311 and a first lower drive circuit 312, a second upper drive circuit 321 and a second lower drive circuit 322, a first bootstrap circuit 41, a second bootstrap circuit 42, and a DC drive voltage Vcc.

[0067] The first switch bridge arm 21 includes a first upper switch Q H1 The first upper switch Q in series H1 The first switch Q L1 The second switch bridge arm 22 includes a second upper switch Q H2 In series with the second upper switch Q H2 The second switch Q L2 The first upper driving circuit 311 and the first lower driving circuit 312 respectively control the first upper switch Q H1 With the first switch Q L1 The second upper driving circuit 321 and the second lower driving circuit 322 respectively control the second upper switch Q H2 With the second lower switch Q L2 .

[0068] The first bootstrap circuit 41 is coupled to the first upper driving circuit 311 and the first upper switch Q H1In this embodiment, the first bootstrap circuit 41 includes a first diode D b1 , the first current limiting resistor R b1 And the first capacitor C b1 The first current limiting resistor R b1 Connect the first diode D in series b1 The first capacitor C b1 Connect the first current limiting resistor R b1 and the first upper driving circuit 311 .

[0069] The second bootstrap circuit 42 is coupled to the second upper driving circuit 321 and the second upper switch Q H2 In this embodiment, the second bootstrap circuit 42 includes a second diode D b2 , the second current limiting resistor R b2 And the second capacitor C b2 The second current limiting resistor R b2 Connect the second diode D in series b2 The second capacitor C b2 Connect the second current limiting resistor R b2 and the second upper driving circuit 321 .

[0070] The DC driving voltage Vcc is used to provide power required by the first upper driving circuit 311 , the first lower driving circuit 312 , the second upper driving circuit 321 and the second lower driving circuit 322 .

[0071] The first switch bridge arm 21 and the second switch bridge arm 22 are alternately driven in a light load state as follows. AC In the positive half cycle, the first switch bridge arm 21 is in the driving operation state, and the second switch bridge arm 22 is in the idle state. At this time, the DC driving voltage Vcc not only provides the power required by the first lower driving circuit 312 to maintain the first lower driving circuit 312 to normally control the first lower switch Q L1 In addition, the DC driving voltage Vcc also supplies power to the first bootstrap circuit 41. Thus, the DC driving voltage Vcc turns on the first diode D b1 , for the first capacitor C b1 Charge, and the first capacitor C b1 The first capacitor voltage is established and maintained to provide the power required by the first upper driving circuit 311, so that the first upper driving circuit 311 can normally control the first upper switch Q H1 . Among them, with the first diode D b1 The first current limiting resistor R in series b1 , used to limit the current in the series branch.

[0072] On the contrary, when the AC power supply V ACIn the negative half cycle, the second switch bridge arm 22 is in the driving operation state, and the first switch bridge arm 21 is in the idle state. At this time, the DC driving voltage Vcc not only provides the power required by the second lower driving circuit 322, but also maintains the second lower driving circuit 322 to normally control the second lower switch Q L2 In addition, the DC driving voltage Vcc also supplies power to the second bootstrap circuit 42. Thus, the DC driving voltage Vcc turns on the second diode D b2 , for the second capacitor C b2 The second capacitor C b2 The second capacitor voltage is established and maintained to provide the power required by the second upper driving circuit 321, so that the second upper driving circuit 321 can normally control the second upper switch Q H2 Among them, the second diode D b2 The second current limiting resistor R b2 , used to limit the current in the series branch.

[0073] See also Figure 8 , is a schematic diagram of the current waveform of the multi-phase switch bridge arms of the multi-phase power converter of the present invention when alternately driven. Since the two-phase switch bridge arms are alternately driven when the load is light, the first input current I IN1 With the second input current I IN2 The total input current I IN The total harmonic distortion is greatly reduced, with excellent current quality.

[0074] Cheng Figures 5 to 8 The multi-phase power converter 100 disclosed in the present invention is not limited to being used for AC-DC conversion, but can also be used for DC-DC conversion with multi-phase power conversion circuits 11-1N connected in parallel. When the multi-phase power converter 100 is used for DC-DC conversion, due to its input power V IN is a DC power supply, and is used to maintain the first capacitor C in the first bootstrap circuit 41. b1 The voltage of the first upper driving circuit 311 is maintained to be greater than the UVLO voltage of the first upper driving circuit 311, and the second capacitor C in the second bootstrap circuit 42 is maintained to be greater than the UVLO voltage of the first upper driving circuit 311. b2 The voltage of the second upper driving circuit 321 is maintained to be greater than the UVLO voltage of the second upper driving circuit 321, so the switch bridge arms 21-22 of each phase in the multi-phase power converter 100 (such as Figure 7 , Figure 5 ), or each phase switch bridge arm 21 to 23 (as shown Figure 6 ) has a fixed switching period, which is related to the first capacitor C b1 , the second capacitor C b2 The capacitance of the first capacitor C b1 , the second capacitor C b2The larger the capacitance, the longer the fixed switching period. In other words, the input power supply V IN When the power supply is a DC power supply, the switch bridge arms 21 to 23 of each phase are driven alternately in a fixed switching cycle to ensure that the corresponding first upper switch Q H1 The first upper driving circuit 311 and the corresponding second upper switch Q H2 The second upper driving circuit 321 operates normally. Incidentally, the multi-phase power converter 100 can simultaneously receive the input power V of AC and DC. IN When the multi-phase power converter 100 has N-phase switch bridge arms, the N-phase switch bridge arms can be driven alternately at an electrical angle of 360 / N degrees of the AC power source VAC (mains power).

[0075] See also Fig. 9 , which is a flow chart of the control method of the multi-phase power converter of the present invention. The multi-phase power converter 100 includes at least two-phase power conversion circuits 11-1N, 21-23, each power conversion circuit 11-1N includes an upper switch Q connected in series H1 ,Q H2 ,Q H3 With the next switch Q L1 ,Q L2 ,Q L3 The control method includes: according to the output current I of the multi-phase power converter 100 OUT , determine the load state of the multi-phase power converter 100 (step S10). Then, when the load state is a light load state, control at least two phase switch bridge arms to be driven alternately (step S20). Since the specific circuit structure and circuit operation description have been detailed in the above content, they will not be repeated here.

[0076] In summary, the present invention has the following features and advantages:

[0077] 1. The driving circuit of the multi-phase power converter of the present invention adopts a single power supply, which is conducive to the design of miniaturization of the circuit volume and reduces the cost.

[0078] 2. Total input current I IN The total harmonic distortion is greatly reduced, which improves the current quality.

[0079] 3. The multi-phase switch bridge arms are driven alternately, and each has an average conduction time, so the power loss is also averaged. Furthermore, the temperature of the switch crystal is also more even. In addition to facilitating the design of heat dissipation and cooling, it is also less likely to cause a large difference in life due to imbalance in usage time.

[0080] The above description is only a detailed description and drawings of the preferred specific embodiments of the present invention, and the features of the present invention are not limited thereto and are not intended to limit the present invention. The entire scope of the present invention shall be based on the claims. All embodiments that are consistent with the concepts of the claims of the present invention and similar variations thereof shall be included in the scope of the present invention. Any changes or modifications that can be easily conceived by any person skilled in the art within the field of the present invention may be covered by the claims of the present disclosure.

Claims

1. A multi-phase power converter, which operates as an input power converter to convert an output power converter, comprising: At least two-phase power conversion circuits, each of which includes a switch bridge arm formed by an upper switch and a lower switch connected in series; as well as a control signal generating unit, which obtains a load state of the multi-phase power converter according to an output current of the multi-phase power converter received, and provides control signals for each of the upper switches and each of the lower switches; Wherein, when the load state is a light load state, the control signal generating unit turns on or off each of the upper switches and each of the lower switches accordingly, so that the at least two-phase switch bridge arms are driven alternately.

2. The multi-phase power converter as claimed in claim 1, wherein when the input power source is an AC power source, the at least two-phase switch bridge arms are driven alternately based on a cycle time of the AC power source.

3. The multi-phase power converter as claimed in claim 2, wherein the at least two-phase switch bridge arms are two-phase; The two-phase switch bridge arms are driven alternately when the positive and negative half cycles of the AC power source are exchanged.

4. The multi-phase power converter as claimed in claim 2, wherein the at least two-phase switch bridge arms are N-phases; The N-phase switch bridge arms are driven alternately at an electrical angle of 360 / N degrees from the AC power source.

5. The multi-phase power converter as claimed in claim 1, wherein the at least two-phase power conversion circuit constitutes a totem pole power factor correction circuit, and the totem pole power factor correction circuit comprises: A first switch bridge arm, comprising a first upper switch and a first lower switch connected in series with the first upper switch; A second switch bridge arm, comprising a second upper switch and a second lower switch connected in series with the second upper switch; A first upper driving circuit and a first lower driving circuit, respectively controlling the first upper switch and the first lower switch; A second upper driving circuit and a second lower driving circuit, controlling the second upper switch and the second lower switch respectively; a first bootstrap circuit, coupling the first upper driving circuit and the first upper switch; a second bootstrap circuit, coupling the second upper driving circuit and the second upper switch; as well as A DC driving voltage is used to provide power required by the first upper driving circuit, the first lower driving circuit, the second upper driving circuit and the second lower driving circuit.

6. The multiphase power converter of claim 5, wherein The first bootstrap circuit comprises: a first diode; a first current limiting resistor, connected in series with the first diode; as well as a first capacitor, connecting the first current limiting resistor and the first upper driving circuit; The second bootstrap circuit comprises: a second diode; a second current limiting resistor, connected in series with the second diode; and A second capacitor is connected to the second current limiting resistor and the second upper driving circuit.

7. The multi-phase power converter as claimed in claim 1, wherein when the input power source is a DC power source, the at least two-phase switch bridge arms are driven alternately with a fixed switching cycle to ensure that an upper driving circuit corresponding to each of the upper switches operates normally.

8. The multi-phase power converter as claimed in claim 7, wherein the at least two-phase switch bridge arms are N-phases; The N-phase switch bridge arms are driven alternately at an electrical angle of 360 / N degrees of the AC power supply.

9. The multi-phase power converter as claimed in claim 1, wherein when the load state is a heavy load state, the control signal generating unit correspondingly turns on or off each of the upper switches and each of the lower switches, so that the at least two-phase switch bridge arms are driven simultaneously.

10. A control method for a multi-phase power converter, the multi-phase power converter comprising at least two-phase power conversion circuits, each of the power conversion circuits comprising a switch bridge arm formed by an upper switch and a lower switch connected in series, the control method comprising: Determining a load state of the multi-phase power converter according to an output current of the multi-phase power converter; as well as When the load state is a light load state, the at least two-phase switch bridge arms are controlled to be driven alternately. 11 . The control method of the multi-phase power converter as claimed in claim 10 , wherein when the input power source is an AC power source, the at least two-phase switch bridge arms are driven alternately based on a cycle time of the AC power source.

12. The control method of the multi-phase power converter as claimed in claim 11, wherein the at least two-phase switch bridge arms are two-phase; The two-phase switch bridge arms are driven alternately when the positive and negative half cycles of the AC power source are exchanged.

13. The control method of the multi-phase power converter as claimed in claim 11, wherein the at least two-phase switch bridge arms are N-phases; The N-phase switch bridge arms are driven alternately at an electrical angle of 360 / N degrees from the AC power source.

14. The control method of the multi-phase power converter as claimed in claim 10, wherein when the input power is a DC power source, the at least two-phase switch bridge arms are driven alternately with a fixed switching cycle to ensure that a driving circuit corresponding to the switch operates normally.

15. The control method of the multi-phase power converter as claimed in claim 14, wherein the at least two-phase switch bridge arms are N-phases; The N-phase switch bridge arms are driven alternately at an electrical angle of 360 / N degrees of the AC power supply.

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