WO2024078022A1 - 功率变换装置及其控制方法、电源系统 - Google Patents

功率变换装置及其控制方法、电源系统 Download PDF

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Publication number
WO2024078022A1
WO2024078022A1 PCT/CN2023/103438 CN2023103438W WO2024078022A1 WO 2024078022 A1 WO2024078022 A1 WO 2024078022A1 CN 2023103438 W CN2023103438 W CN 2023103438W WO 2024078022 A1 WO2024078022 A1 WO 2024078022A1
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Prior art keywords
power conversion
power
conversion modules
phase shift
switches
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PCT/CN2023/103438
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English (en)
French (fr)
Inventor
吴佳磊
孙梓源
江竑旭
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华为数字能源技术有限公司
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Publication of WO2024078022A1 publication Critical patent/WO2024078022A1/zh

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0038—Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1584—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
    • H02M3/1586—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel switched with a phase shift, i.e. interleaved
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/219—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration

Definitions

  • the present application relates to the field of circuit technology, and in particular to a power conversion device and a control method thereof, and a power supply system.
  • each power conversion module provides a part of the power of the entire power system, which can reduce the stress of the power switch in each power conversion module.
  • each power conversion module has parasitic parameters such as parasitic inductance and parasitic capacitance.
  • the parasitic parameters are prone to resonate, resulting in inevitable voltage oscillations at both ends of the power switch. Voltage oscillations will cause the voltage stress of the power switch to increase, and the power switch is at risk of overvoltage failure.
  • the input-parallel output-parallel (IPOP) circuit topology requires an increase in the number of power switches, making the parasitic parameters of the circuit more complex. When multiple power conversion modules work synchronously, a larger number of power switches operate at high frequency at the same time, which makes the voltage oscillation problem more significant and the stress risk of the power switch greater.
  • the present application provides a power conversion device and a control method thereof, and a power supply system, which can effectively suppress the voltage oscillation across the power switch without increasing the hardware cost, reduce the voltage stress of the power switch, and improve the safety and stability of the power conversion device and the power supply system.
  • the present application provides a power conversion device, which includes a controller and n power conversion modules, n is a positive integer greater than 1, the n power conversion modules are connected in parallel, the controller is electrically connected to each power conversion module, each power conversion module includes a power switch, the controller is used to output a first control signal to the n power conversion modules to control the n power conversion modules to work synchronously, and determine the phase shift angles corresponding to the n power conversion modules according to the voltage oscillation frequency across the power switches with the same serial number in the n power conversion modules working synchronously, and then output a second control signal to the n power conversion modules according to the phase shift angles corresponding to the n power conversion modules to control the n power conversion modules to work in staggered phases.
  • the staggered operation of n power conversion modules means that the circuit currents of the n power conversion modules are not synchronized. Based on this, when the parasitic inductance in the power conversion module charges the power switch due to the freewheeling effect, the freewheeling of the parasitic inductance will not be synchronized. In this way, the superposition of the freewheeling effects of the parasitic inductances of multiple power conversion modules can be alleviated, and the voltage oscillations at both ends of the power switches at the same position in the n power conversion modules are also made asynchronous.
  • the voltage oscillations of different power conversion modules can be offset, so that the voltage oscillations of each power conversion module are effectively suppressed, and the peak voltage is reduced, which is beneficial to the stabilization and reduction of the voltage stress of the power switch in the power conversion module.
  • the power conversion device provided by the present application can effectively suppress the voltage oscillations at both ends of the power switch without increasing the hardware cost, and reduce and Stabilize the voltage stress of the power switch, improve the safety and stability of the power conversion device, and enhance the product competitiveness of the power conversion device.
  • the controller is used to obtain the voltage oscillation frequency across all power switches in the n power conversion modules when the n power conversion modules are working synchronously, and determine the phase shift angles corresponding to the multiple power switches with the same serial number according to the voltage oscillation frequency across the power switches with the same serial number in the n power conversion modules.
  • the phase shift angles corresponding to the multiple power switches with the same serial number are used to characterize the time intervals at which the multiple power switches with the same serial number sequentially act. In this way, the phase shift angles corresponding to the multiple power switches with the same serial number in the n power conversion modules can constitute the phase shift angles corresponding to the n power conversion modules.
  • the controller is used to phase-shift the first control signals corresponding to the multiple power switches with the same serial number according to the phase shift angles corresponding to the multiple power switches with the same serial number, so as to generate a second control signal to n power conversion modules, wherein the second control signals corresponding to the multiple power switches with the same serial number are sequentially phase-differed by the corresponding phase shift angles.
  • the multiple power switches with the same serial number can be operated sequentially, thereby realizing phase-shifting operation.
  • the second control signals corresponding to multiple power switches with the same serial number may have the same phase shift angles that are sequentially different in phase. In this way, under the control of the corresponding second control signal, multiple power switches with the same serial number may operate sequentially at the same time interval. In addition, the same phase shift angle is also beneficial to reduce the amount of calculation of the controller and improve the signal processing efficiency of the controller.
  • the second control signals corresponding to multiple power switches with the same serial number may have different phase shift angles that are sequentially different in phase. In this way, under the control of the corresponding second control signal, multiple power switches with the same serial number may operate sequentially at different time intervals. In addition, different phase shift angles also make it easier for the controller to flexibly control the power conversion module and more easily improve the voltage oscillation suppression effect.
  • the phase shift angles corresponding to power switches of different serial numbers in n power conversion modules may be the same. Based on such an implementation, the overall phase shift of a power conversion module can be achieved, that is, the phase shift at the module level can be achieved. Of course, the phase shift angles corresponding to power switches of different serial numbers in n power conversion modules may also be different. Based on such an implementation, the independent phase shift of each power switch in a power conversion module can be achieved, that is, the phase shift at the device level can be achieved.
  • the calculation formula of the phase shift angle is:
  • ⁇ i is the phase shift angle
  • i is the serial number of the power switch in the power conversion module
  • Tos is the voltage oscillation frequency across the power switch
  • k is the phase shift angle adjustment coefficient, 0 ⁇ k ⁇ 1.
  • the controller is used to fine-tune the calculated phase shift angle ⁇ i to obtain more phase shift angles, so that the phase shift control of the n power conversion modules is more flexible.
  • each of the n power conversion modules is any one of a DC-DC conversion module, an AC-AC conversion module, a DC-AC conversion module, and an AC-DC conversion module.
  • the power conversion device of the present application can be flexibly applied to any scenario of DC-DC conversion, AC-AC conversion, DC-AC conversion, and AC-DC conversion, and has a very wide range of applications.
  • the present application provides a control method for a power conversion device, a control method for a power conversion device, wherein the power conversion device includes a controller and n power conversion modules, n is a positive integer greater than 1, the n power conversion modules are connected in parallel, the controller is electrically connected to each of the n power conversion modules, and each power conversion module includes a power switch.
  • the control method includes outputting a first control signal to the n power conversion modules so that the n power conversion modules work synchronously under the control of the first control signal, and then determining the phase shift angle corresponding to the n power conversion modules according to the voltage oscillation frequency across the power switches with the same serial number in the n power conversion modules working synchronously, and then outputting a second control signal to the n power conversion modules according to the phase shift angle corresponding to the n power conversion modules, so that the n power conversion modules work in staggered phases under the control of the second control signal.
  • the circuit currents of the n power conversion modules can be asynchronous, based on which the superposition of the freewheeling effect of the parasitic inductance of the multiple power conversion modules can be alleviated, and the voltage oscillations at both ends of the power switches at the same position in the n power conversion modules can also be made asynchronous.
  • the voltage oscillations of different power conversion modules can be superimposed and offset, so that the voltage oscillations of each power conversion module are effectively suppressed, and the peak voltage is reduced, which is beneficial to the stability and reduction of the voltage stress of the power switch in the power conversion module. Therefore, without increasing the hardware cost, the control method provided by the present application can effectively suppress the voltage oscillations at both ends of the power switch, reduce the voltage stress of the power switch, and improve the safety and stability of the power conversion device.
  • the control method when determining the phase shift angle corresponding to n power conversion modules, specifically obtains the voltage oscillation frequency across all power switches in the n power conversion modules when the n power conversion modules are working synchronously, and then determines the phase shift angle corresponding to multiple power switches with the same serial number according to the voltage oscillation frequency across the power switches with the same serial number in the n power conversion modules, wherein the phase shift angle corresponding to multiple power switches with the same serial number is used to characterize the time interval for multiple power switches with the same serial number to act in sequence.
  • the phase shift angle corresponding to multiple power switches with the same serial number in the n power conversion modules can constitute the phase shift angle corresponding to the n power conversion modules.
  • the control method can phase-shift the first control signals corresponding to the multiple power switches with the same serial number according to the phase shift angles corresponding to the multiple power switches with the same serial number to generate a second control signal to n power conversion modules, wherein the second control signals corresponding to the multiple power switches with the same serial number are sequentially phase-differed by the corresponding phase shift angles.
  • the multiple power switches with the same serial number can be operated sequentially, thereby achieving phase-shifting operation.
  • the calculation formula of the phase shift angle is:
  • ⁇ i is the phase shift angle
  • i is the serial number of the power switch in the power conversion module
  • Tos is the voltage oscillation frequency across the power switch
  • k is the phase shift angle adjustment coefficient, 0 ⁇ k ⁇ 1.
  • the present application provides a power supply system for supplying power to electrical equipment
  • the power supply system includes a power supply and a power conversion device
  • the power conversion device is electrically connected between the power supply and the electrical equipment
  • the power conversion device includes a controller and n power conversion modules, n is a positive integer greater than 1, the n power conversion modules are connected in parallel
  • the controller is electrically connected to the n power conversion modules, and is used to control the n power conversion modules to operate in staggered phases, so as to suppress the voltage oscillations across the power switches in the n power conversion modules, reduce the voltage stress of the power switches, and improve the safety and stability of the power supply system.
  • FIG. 1 is a schematic diagram of voltage oscillation across a power switch when multiple power conversion modules operate synchronously.
  • FIG. 2 is a schematic diagram of a power conversion device provided in an embodiment of the present application.
  • FIG. 3 is a circuit diagram of an implementation of the power conversion modules in FIG. 2 being connected in parallel.
  • FIG. 4 is a circuit diagram of an implementation of two power conversion modules in FIG. 3 connected in parallel.
  • FIG. 5 is a timing diagram of control signals of the two power conversion modules in FIG. 4 .
  • FIG. 6 is a schematic diagram of voltage oscillations across a power switch when the two power conversion modules in FIG. 4 operate out of phase.
  • FIG. 7 is a schematic diagram of the current of the inductor unit when the two power conversion modules in FIG. 4 operate in phase shift.
  • FIG8 is a flow chart of a control method for a power conversion device provided in an embodiment of the present application.
  • FIG. 9 is a schematic diagram of a power supply system provided in an embodiment of the present application.
  • Power conversion device 100 Description of main component symbols Power conversion device 100, 100a Power conversion module 1, 1a, 1b Switching unit 11 Inductor unit 12, 12a, 12b Controller 2 Filter unit 3 Power System 1000 Power supply 200 Electrical equipment 300
  • connection relationship described in this application refers to direct or indirect connection.
  • the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.
  • A can be directly connected to C, and C can be directly connected to B, so that A and B are connected through C.
  • the "A connected to B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.
  • A/B can mean A or B.
  • “And/or” in this article is only a way to describe the association relationship of associated objects, indicating that there can be three relationships.
  • a and/or B can mean: A exists alone, A and B exist at the same time, and B exists alone.
  • each power conversion module provides a part of the power of the entire power system, which can reduce the stress of the power switch in each power conversion module.
  • each power conversion module has parasitic parameters such as parasitic inductance and parasitic capacitance.
  • parasitic inductance When a power switch in a power conversion module switches on and off, the circuit current will change, causing the parasitic parameters to resonate.
  • the parasitic inductance will continue to charge the power switch at the moment of the power switch switching state due to the freewheeling effect, which allows the parasitic capacitor to charge and store energy. After the parasitic capacitor is charged, it releases energy to store energy for the parasitic inductance, and so on.
  • the electric energy transmitted by the parasitic parameters will gradually be consumed during the charge and discharge process of the cycle. This causes the voltage at both ends of the power switch to oscillate.
  • the voltage waveform at both ends of the power switch fluctuates in a decaying manner, generating several peaks and troughs.
  • the voltage at the peak is the peak voltage
  • the voltage at the trough is the trough voltage.
  • the voltage of the first peak is the largest, and this voltage is the peak voltage.
  • the spike voltage will increase the voltage stress of the power switch, resulting in the risk of overvoltage failure of the power switch.
  • the embodiments of the present application provide a power conversion device and a control method thereof, and a power supply system, which can be used without adding hardware.
  • the voltage oscillation at both ends of the power switch can be effectively suppressed, the voltage stress of the power switch can be reduced, and the voltage stress of the power switch can be stabilized, thereby improving the safety and stability of the power conversion device and the power supply system.
  • FIG. 2 is a schematic diagram of the structure of a power conversion device 100 provided in one embodiment of the present application.
  • the power conversion device 100 includes n power conversion modules 1 and a controller 2.
  • n is a positive integer greater than 1.
  • the n power conversion modules 1 are connected in parallel. That is, the input sides of the n power conversion modules 1 are connected in parallel, and the output sides of the n power conversion modules 1 are also connected in parallel, thereby forming an input-parallel output-parallel (IPOP) structure.
  • IPIP input-parallel output-parallel
  • the n power conversion modules 1 all use the same circuit, which can avoid the situation where some power conversion modules 1 bear greater power due to different circuits, thereby causing device overstress and damage to the device.
  • each power conversion module 1 includes m power switches, where m is a positive integer.
  • the power conversion module 1 can change the voltage by turning on or off the m power switches, thereby realizing the voltage conversion function.
  • the power switch of the power conversion module 1 can be a metal oxide semiconductor field effect transistor (metal-oxide-semiconductor field-effect transistor, MOSFET), an insulated gate bipolar transistor (insulated gate bipolar transistor, IGBT), a switch circuit formed by connecting multiple MOSFETs in parallel or in series, a switch circuit formed by connecting multiple IGBTs in parallel or in series, a switch circuit formed by connecting a MOSFET and a reverse-connected diode in parallel, or a switch circuit formed by connecting an IGBT and a reverse-connected diode in parallel, which is not specifically limited here.
  • MOSFET metal-oxide-semiconductor field-effect transistor
  • IGBT insulated gate bipolar transistor
  • a switch circuit formed by connecting multiple MOSFETs in parallel or in series a switch circuit formed by connecting multiple IGBTs in parallel or in series
  • a switch circuit formed by connecting a MOSFET and a reverse-connected diode in parallel or a switch circuit formed by connecting an IGBT
  • the m power switches can use devices with consistent internal parameters to reduce impurity inductance and distributed capacitance.
  • the gates of the m power switches can be used to receive control signals to turn on and off under the control of the control signals.
  • the power switch can be turned on when a high level in the control signal is received, and turned off when a low level in the control signal is received.
  • the turning on and off of the power switch refers to the turning on and off of the switching device in the power switch.
  • each power conversion module 1 includes a switch unit 11 and an inductor unit 12 .
  • the switch unit 11 includes four power switches Q1 to Q4.
  • the inductor unit 12 includes an inductor L1.
  • the source of the power switch Q1 is connected to the drain of the power switch Q2.
  • the source of the power switch Q3 is connected to the drain of the power switch Q4.
  • the source of the power switch Q2 is connected to the source of the power switch Q4.
  • One end of the inductor L1 is connected between the source of the power switch Q1 and the drain of the power switch Q2, and the other end of the inductor L1 is connected between the source of the power switch Q3 and the drain of the power switch Q4.
  • the power conversion module 1 can constitute a buck-boost circuit. Specifically, when the power conversion module 1 is working, the power switches Q1 and Q2 are complementary turned on, and the power switches Q3 and Q4 are complementary turned on.
  • the inductor L1 stores and releases energy during the on-off process of the power switches Q1 to Q4, so that the power conversion module 1 can achieve the boost/buck function.
  • the power conversion module 1 can change the amount of energy stored in the inductor L1 by adjusting the on-off time of the power switch, thereby achieving the boost/buck function.
  • each filter unit 3 can include at least one capacitor, and can also include at least one capacitor and at least one resistor connected to each other, which is not specifically limited here. Two filter units 3 can be used to filter the voltage on both sides of the connected power conversion modules 1.
  • each power conversion module 1 can use any one of the two sides of the H-bridge topology as the input side and the other side as the output side. Therefore, each power conversion module 1 is a bidirectional power conversion module, which can realize bidirectional energy transfer. Based on this, the power conversion device 100 can be applied to applications where bidirectional energy transfer is required.
  • each power conversion module 1 in the embodiment of the present application can also adopt a bidirectional power conversion module of other topological structures.
  • the power conversion module 1 can also form a full-bridge topological structure.
  • the power conversion module 1 is a bidirectional LLC resonant full-bridge circuit.
  • the power conversion module 1 can also form a half-bridge topological structure.
  • the power conversion module 1 is a bidirectional LLC resonant half-bridge circuit. That is to say, in the embodiment of the present application, the topological structure of the power conversion module 1 is not limited, it is only necessary to ensure that the power conversion module 1 has a power switch, and the voltage conversion function can be realized by turning on and off the power switch.
  • each power conversion module 1 can also be a unidirectional power conversion module that can realize unidirectional energy transfer, for example, it can be a buck converter, a boost converter, etc. Based on this, the power conversion device 100 can be applied to applications where unidirectional energy transfer is required.
  • the power conversion module 1 is a DC-DC conversion module.
  • the power conversion module 1 may also be any one of a DC-AC conversion module, an AC-DC conversion module, and an AC-AC conversion module, which is not specifically limited here.
  • the power conversion module 1 is a single power converter. In other embodiments, the power conversion module 1 may also be composed of multiple power converters connected in series, in parallel, or in series and parallel, which is not specifically limited here.
  • the controller 2 is electrically connected to the n power conversion modules 1 and can be used to control the voltage conversion of the n power conversion modules 1 .
  • controller 2 can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the above program.
  • CPU central processing unit
  • ASIC application-specific integrated circuit
  • the controller 2 can generate a control signal to each power switch in the n power conversion modules 1 based on a pulse width modulation (PWM) method, a pulse frequency modulation (PFM) method, a mixture of PWM and PFM, or other methods to control the on and off state of each power switch, thereby controlling the working process of the n power conversion modules 1.
  • PWM pulse width modulation
  • PFM pulse frequency modulation
  • controller 2 is also used to perform phase shift control on the n power conversion modules 1 so that the n power conversion modules 1 can work in staggered phases, thereby effectively suppressing the voltage oscillation across the power switches in the n power conversion modules 1 and reducing the voltage stress oscillation amplitude of the power switches.
  • the power conversion module 1a has four power switches Q1 to Q4 and an inductor unit 12a (i.e., inductor L1)
  • the power conversion module 1b has four power switches Q1' to Q4' and an inductor unit 12b (i.e., inductor L1').
  • the power switches Q1 and Q1' have the same serial number and position in the power conversion module
  • the power switches Q2 and Q2' have the same serial number and position in the power conversion module
  • the power switches Q3 and Q3' have the same serial number and position in the power conversion module
  • the power switches Q4 and Q4' have the same serial number and position in the power conversion module.
  • the controller 2 is used to generate a first control signal to the power conversion modules 1a and 1b to control the power conversion modules 1a and 1b to work synchronously.
  • synchronous operation means that the working conditions of different power conversion modules are consistent.
  • the power conversion module 1a when the power conversion module 1a is started, the power conversion module 1b is also started at the same time.
  • synchronous operation can be understood as the first control signals corresponding to different power conversion modules are consistent in phase. Therefore, synchronous operation can also be called in-phase operation.
  • asynchronous operation means that the working conditions of different power conversion modules are inconsistent. For example, the power conversion module 1a is started first, and the power conversion module 1b is started later. That is, there is a phase difference between the control signals corresponding to the power conversion module 1a and the power conversion module 1b. Therefore, asynchronous operation can also be called out-of-phase operation.
  • the power switches Q1 and Q1' operate synchronously, the power switches Q2 and Q2' operate synchronously, the power switches Q3 and Q3' operate synchronously, and the power switches Q4 and Q4' operate synchronously.
  • the power switches Q1 and Q2 are turned on complementary, and the power switches Q3 and Q4 are turned on complementary.
  • the first control signals of the power switches Q1 and Q1', Q4 and Q4' are at a low level, so the power switches Q1 and Q1', Q4 and Q4' are in an off state.
  • the first control signals of the power switches Q2 and Q2', Q3 and Q3' are at a high level, so the power switches Q2 and Q2', Q3 and Q3' are in an on state.
  • the first control signals of power switches Q1 and Q1' jump to a high level, so power switches Q1 and Q1' switch from an off state to an on state.
  • the first control signals of power switches Q2 and Q2' jump to a low level, so power switches Q2 and Q2' switch from an on state to an off state.
  • the levels of the first control signals of power switches Q3 and Q3', Q4 and Q4' remain unchanged, so power switches Q3 and Q3' remain on, and Q4 and Q4' remain off.
  • the levels of the first control signals of power switches Q1 and Q1', Q2 and Q2' remain unchanged, so power switches Q1 and Q1' remain on, and Q2 and Q2' remain off.
  • the first control signals of power switches Q4 and Q4' jump to a high level, so power switches Q4 and Q4' switch from an off state to an on state.
  • the first control signals of power switches Q3 and Q3' jump to a low level, so power switches Q3 and Q3' switch from an on state to an off state.
  • the levels of the first control signals of power switches Q1 and Q1', Q2 and Q2' remain unchanged, so power switches Q1 and Q1' remain on, and Q2 and Q2' remain off.
  • the first control signals of power switches Q3 and Q3' jump to a high level, so power switches Q3 and Q3' switch from an off state to an on state.
  • the first control signals of power switches Q4 and Q4' jump to a low level, so power switches Q4 and Q4' switch from an on state to an off state.
  • the voltage oscillation frequency across the power switch Q1 is equal to the voltage oscillation frequency across the power switch Q1'. Therefore, when the voltage oscillation frequency across the power switch Q1 is obtained, the voltage oscillation frequency across the power switch Q1' is also obtained. The same is true for the power switches Q2 and Q2', Q3 and Q3', and Q4 and Q4', which will not be repeated here.
  • the power switches Q1 and Q2 are connected in series and form one side of the H-bridge topology
  • the power switches Q3 and Q4 are connected in series and form the other side of the H-bridge topology
  • the states of the power switches Q1 and Q2 are complementary
  • the states of the power switches Q3 and Q4 are complementary. Therefore, when the power switch Q1 is activated, the voltage oscillation frequency across the power switch Q1 is equal to the voltage oscillation frequency at one side of the H-bridge topology formed by the power switches Q1 and Q2. Therefore, when the voltage oscillation frequency at one side of the H-bridge topology where the power switch Q1 is located is obtained, the voltage oscillation frequency across the power switch Q1 is also obtained. The same is true for the power switches Q2 ⁇ Q4 and Q1' ⁇ Q4' in the power conversion module 1b, so they will not be repeated.
  • the controller 2 After obtaining the voltage oscillation frequencies at both ends of the power switches Q1-Q4, Q1'-Q4', the controller 2 is further used to obtain the voltage oscillation frequencies according to the voltage oscillation frequencies. Determine the phase shift angles corresponding to the power conversion modules 1a and 1b.
  • the phase shift angle corresponding to the power conversion modules 1a and 1b is composed of the phase shift angles corresponding to the power switches with the same serial number in the power conversion modules 1a and 1b. Therefore, the phase shift angles corresponding to the power conversion modules 1a and 1b include the phase shift angle ⁇ 1 corresponding to the power switches Q1 and Q1', the phase shift angle ⁇ 2 corresponding to the power switches Q2 and Q2', the phase shift angle ⁇ 3 corresponding to the power switches Q3 and Q3', and the phase shift angle ⁇ 4 corresponding to the power switches Q4 and Q4'.
  • the phase shift angle is used to characterize the time interval for multiple power switches with the same serial number to act in sequence.
  • the controller 2 may determine the phase shift angle according to the following calculation formula:
  • i is the serial number corresponding to the power switch in the power conversion module 1.
  • i is 1, 2, 3 or 4.
  • ⁇ i represents the phase shift angle corresponding to the multiple power switches with the same serial number i.
  • Tos is the voltage oscillation frequency across the corresponding power switch.
  • k is the phase shift angle adjustment coefficient, -1 ⁇ k ⁇ 1.
  • phase shift angle is 0, indicating that multiple power switches with the same serial number operate synchronously.
  • the controller 2 is further used to perform phase shift control on the power conversion modules 1a and 1b according to the phase shift angles corresponding to the power conversion modules 1a and 1b.
  • the controller 2 is used to phase-shift the first control signals of the corresponding multiple power switches with the same serial number in the power conversion modules 1a and 1b according to the phase shift angles corresponding to the multiple power switches with the same serial number, so as to generate the second control signal.
  • the second control signals corresponding to the multiple power switches with the same serial number are sequentially phase-shifted by the phase shift angle.
  • the second control signals corresponding to the power switches Q1 in the first power conversion module and the second power conversion module differ in phase by a phase shift angle
  • the second control signals corresponding to the power switches Q1 in the second power conversion module and the third power conversion module also differ in phase by a phase shift angle, and so on.
  • phase shift angles corresponding to every two power switches of the same serial number can be the same.
  • the phase shift angles corresponding to every two power switches of the same serial number can also be fine-tuned according to actual conditions, so the phase shift angles corresponding to every two power switches of the same serial number can also be different.
  • the first control signals of multiple power switches with the same serial number can all be phase-shifted, and the phase shift can be to make the phase of the second control signal advance or to make the phase of the second control signal lag, as long as the second control signals of the multiple power switches with the same serial number are phase-differed by the phase shift angle in sequence.
  • the first control signal of one of the power switches may not be phase-shifted, while the first control signals of the other power switches may be phase-shifted.
  • the phase shift of the first control signal corresponding to the power switches Q1 to Q4 in the power conversion module 1a is 0, while the first control signals corresponding to the power switches Q1' to Q4' in the power conversion module 1b are all phase shifted. Therefore, referring to the solid line in FIG5, the second control signal of the power switches Q1 to Q4 is the same as the first control signal of the power switches Q1 to Q4. The second control signal of the power switches Q1' to Q4' can be referred to the dotted line in FIG5. There is a phase difference between the second control signal of the power switches Q1' to Q4' and the second control signal of the power switches Q1 to Q4.
  • the second control signal of the power switch Q1 ′ lags behind the second control signal of the power switch Q1 by a phase shift angle ⁇ 1 .
  • the second control signal of the power switch Q2 ′ lags behind the second control signal of the power switch Q2 by a phase shift angle ⁇ 2 .
  • the second control signal of the power switch Q3 ′ lags behind the second control signal of the power switch Q3 by a phase shift angle ⁇ 3 .
  • the second control signal of the power switch Q4 ′ lags behind the second control signal of the power switch Q4 by a phase shift angle ⁇ 4 .
  • the second control signal of the power switch Q1 changes to a high level, so the power switch Q1 switches from the off state to the on state.
  • the second control signal of the power switch Q2 changes to a low level, so the power switch Q2 switches from the on state to the off state.
  • the levels of the second control signals of the power switches Q1' and Q2' remain unchanged, so the power switch Q1' remains off and Q2' remains on.
  • the levels of the second control signals of the power switches Q3 and Q3', Q4 and Q4' remain unchanged, so the power switches Q3 and Q3' remain on and Q4 and Q4' remain off.
  • the second control signal of the power switch Q1' jumps to a high level, and the second control signal of the power switch Q2' jumps to a low level, so that the power switch Q1' switches from the off state to the on state, and the power switch Q2' switches from the on state to the off state.
  • the power switches Q3 and Q3' remain on, and Q4 and Q4' remain off.
  • the second control signal of power switch Q3 jumps to a low level, so power switch Q2 switches from the on state to the off state.
  • the second control signal of power switch Q4 jumps to a high level, so power switch Q4 switches from the off state to the on state.
  • the second control signal of Q3' remains at the original high level, and the second control signal of power switch Q4' remains at the original low level, so power switches Q3' and Q4' do not act.
  • the levels of the second control signals of power switches Q1 and Q1', Q2 and Q2' remain unchanged, so power switches Q1 and Q1' remain on, and Q2 and Q2' remain off.
  • the second control signal of Q3' jumps to a low level, and the second control signal of the power switch Q4' jumps to a high level, so that the power switch Q3' switches from the on state to the off state, and the power switch Q4' switches from the off state to the on state.
  • the power switches Q1 and Q1' remain on, and Q2 and Q2' remain off.
  • phase shift angles ⁇ 1 to ⁇ 4 can be expressed as the following matrix A:
  • phase shift angles ⁇ 1 - ⁇ 4 are equal, which is equivalent to the controller 2 performing overall phase shift on the first control signals corresponding to all power switches of the power conversion modules 1a and 1b. Therefore, this situation can be understood as module-level phase shift.
  • phase shift angles ⁇ 1 to ⁇ 4 may also be unequal. It can be understood that the unequal phase shift angles ⁇ 1 to ⁇ 4 are equivalent to the controller 2 independently shifting the phases of the first control signals corresponding to the four power switches of the two power conversion modules 1a and 1b. Therefore, this situation can be understood as a phase shift at the device level.
  • the power switches Q1 and Q1’, Q2 and Q2’, Q3 and Q3’, Q4 and Q4’ with the same serial number in the power conversion modules 1a and 1b all operate in staggered phases, and therefore, the power conversion modules 1a and 1b realize staggered phase operation.
  • the circuit current of the power conversion module 1 will change with the action of the power switch.
  • the current of the inductor unit 12a will change with the action of the power switches Q1 to Q4
  • the current of the inductor unit 12b will change with the action of the power switches Q1' to Q4'.
  • the current of the inductor unit 12b will also lag behind the current of the inductor unit 12a. That is, the current of the inductor unit 12a and the current of 12b will be out of phase.
  • the current waveform of the inductor unit 12a is represented by a solid line
  • the current waveform of the inductor unit 12b is represented by a dotted line.
  • the power switches Q1 and Q1' are used as examples for explanation. Please refer to FIG7. Since the power switch Q1 is activated at time t2 and the power switch Q1' is activated at time t2', the voltage across the power switch Q1 first generates voltage oscillations, and the voltage across the power switch Q1' generates voltage oscillations later. Correspondingly, the voltage waveform corresponding to the voltage across the power switch Q1' (see the dotted line in FIG7) lags behind the voltage waveform corresponding to the voltage across the power switch Q1 (see the dotted line in FIG7).
  • the voltage waveform corresponding to the power switch Q1 After the voltage waveform corresponding to the power switch Q1 reaches the first peak, the voltage waveform corresponding to the power switch Q1' will start to rise to the first peak. In other words, the voltage waveform corresponding to the power switch Q1' starts to rise to the peak voltage during the period when the voltage waveform corresponding to the power switch Q1 drops from the peak voltage.
  • At least a portion of the peaks and at least a portion of the valleys in the voltage waveforms corresponding to the two power switches Q1 and Q1' can correspond to each other. That is, at the same time, at least a portion of the peak voltage of the power switch Q1 can correspond to at least a portion of the valley voltage of the power switch Q1', and at least a portion of the valley voltage of the power switch Q1 can correspond to at least a portion of the peak voltage of the power switch Q1'.
  • the peak voltage and the valley voltage will cancel each other out after being superimposed. Therefore, when at least a portion of the peaks and at least a portion of the valleys in the voltage waveforms corresponding to the two power switches Q1 and Q1' correspond, the corresponding peak voltage and valley voltage can be superimposed and cancel each other out, so that the voltage oscillation amplitude at both ends of the power switches Q1 and Q1' can be reduced, and the voltage oscillation can be effectively suppressed. Therefore, the voltage waveform corresponding to the power switch Q1 (see the solid line in FIG. 7 ) and the voltage waveform corresponding to the power switch Q1' become gentle, and the fluctuation amplitude becomes smaller.
  • the out-of-phase operation of the power switches Q1 and Q1’ can alleviate the superposition of the freewheeling effect of the parasitic inductance in the power conversion modules 1a and 1b, suppress the voltage oscillation across the power switches Q1 and Q1’, and reduce the peak voltage, which is beneficial to the reduction and stabilization of the voltage stress of the power switches Q1 and Q1’.
  • phase shift control process when the power switches Q2 and Q2', Q3 and Q3', Q4 and Q4' are all out of phase, the voltage oscillations at both ends of the power switches Q2 and Q2', Q3 and Q3', Q4 and Q4' can also be effectively suppressed, and the voltage stress of the power switches Q2 and Q2', Q3 and Q3', Q4 and Q4' can also be reduced and become stable. Therefore, the overstress risk of all power switches of the entire power conversion modules 1a and 1b can be reduced.
  • the controller 2 can perform phase shift control on more than three power conversion modules 1 according to the above process, so that more than three power conversion modules 1 can work in staggered phases. Furthermore, the voltage oscillations at both ends of the power switches in more than three power conversion modules 1 can be effectively suppressed, and the voltage stress can be reduced and stabilized.
  • the power conversion device 100 of the embodiment of the present application can reduce the voltage stress of the power switch without adding circuits/devices by making n power conversion modules 1 work in staggered phases, and make the voltage stress stable, thereby reducing the risk of overstress of the power switch.
  • the embodiment of the present application further provides a control method for a power conversion device, which is applicable to the power conversion device 100 described above.
  • control method of the power conversion device includes the following steps:
  • Step S1 the controller 2 outputs a first control signal to n power conversion modules 1, so that the n power conversion modules 1 work synchronously under the control of the first control signal.
  • n is a positive integer greater than 1.
  • step S1 can be specifically as follows:
  • the controller 2 outputs a first control signal to the power switches with the same serial number in the n power conversion modules 1.
  • the power switches with the same serial number in the n power conversion modules 1 act synchronously under the control of the first control signal, so that the n power conversion modules 1 work synchronously.
  • Step S2 the controller 2 determines the phase shift angles corresponding to the n power conversion modules 1 according to the voltage oscillation frequencies across the power switches with the same sequence number in the n power conversion modules working synchronously.
  • Step S3 The controller 2 outputs a second control signal to the n power conversion modules according to the phase shift angles corresponding to the n power conversion modules 1. 1, so that the n power conversion modules 1 work in staggered phases under the control of the second control signal.
  • the phase shift angles corresponding to n power conversion modules 1 include the phase shift angles corresponding to multiple power switches with the same serial number in the n power conversion modules 1, wherein the phase shift angles corresponding to multiple power switches with the same serial number are used to characterize the time intervals in which the multiple power switches with the same serial number act in sequence.
  • step S2 may include the following steps:
  • Step S21 when n power conversion modules 1 work synchronously, the controller 2 obtains the voltage oscillation frequency across the power switch in each power conversion module 1 .
  • Step S22 the controller 2 determines the phase shift angles corresponding to the multiple power switches with the same serial number according to the voltage oscillation frequency across the power switches with the same serial number in the n power conversion modules 1.
  • the controller 2 determines the phase shift angles corresponding to the multiple power switches with the same serial number according to the voltage oscillation frequency across the power switches with the same serial number in the n power conversion modules 1.
  • step S3 is specifically as follows:
  • the controller 2 performs phase shifting on the first control signals of the corresponding multiple power switches with the same serial number according to the phase shift angles corresponding to the multiple power switches with the same serial number in the n power conversion modules 1 to generate the second control signal.
  • the second control signals corresponding to the multiple power switches with the same serial number are sequentially phase-shifted by the phase shift angle.
  • the multiple power switches with the same serial number in the n power conversion modules 1 act in sequence with the phase shift angle as the time interval, that is, the multiple power switches with the same serial number act in staggered phases. In this way, the n power conversion modules 1 can achieve staggered phase operation.
  • the voltage oscillations at both ends of the multiple power switches with the same serial number can be made asynchronous.
  • the voltage stress oscillations at both ends of the multiple power switches with the same serial number can offset each other, thereby reducing the voltage stress oscillation amplitude at both ends of the power switch, reducing the voltage stress and making it stable, and thus reducing the risk of overstress of the power switch.
  • the present embodiment also provides a power supply system 1000.
  • the power supply system 1000 can be used to electrically connect to an electric device 300 to supply power to the electric device 300.
  • the electric device 300 includes but is not limited to communication equipment, computers, electric vehicles, and the like.
  • the power supply system 1000 includes a power supply 200 and a power conversion device 100a.
  • the power conversion device 100a is electrically connected between the power supply 200 and the power consumption device 300, and is used to obtain the voltage of the power supply 200 and convert the voltage of the power supply 200 into the voltage required by the power consumption device 300.
  • the power conversion device 100a can be the above-mentioned power conversion device 100.
  • the power supply system 1000 is a DC power supply system.
  • the power conversion device 100a is a DC-DC (Direct Current to Direct Current) conversion device, which can be used to convert one DC voltage into another DC voltage.
  • DC-DC Direct Current to Direct Current
  • the power supply 200 may be an alternating current to direct current (AC-DC) conversion module.
  • the AC-DC conversion module is electrically connected to the power conversion device 100a, and the AC-DC conversion module may be used to convert an AC voltage into a DC voltage and output the DC voltage to the power conversion device 100a.
  • the power source 200 may also be a battery.
  • the battery is electrically connected to the power conversion device 100a.
  • the power conversion device 100a can draw power from the battery.
  • the power conversion device 100a can also supply power to the battery to charge the battery.
  • the power supply system 1000 may further include a DC busbar.
  • the DC busbar is electrically connected to the power conversion device 100a.
  • the DC busbar may be used to electrically connect the power consumption device 300 to output the DC voltage generated by the power conversion device 100a to the power consumption device 300.
  • the functional units in the embodiments of the present application may all be integrated into one processing unit, or each unit may be a separate unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.
  • the integrated unit of the present application is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.
  • the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in each embodiment of the present application.
  • the aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROM, RAM, disks, or optical disks.

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Abstract

本申请提供一种功率变换装置及其控制方法、电源系统，其中功率变换装置包括控制器和n个功率变换模块，n为大于1的正整数，n个功率变换模块并联，n个功率变换模块均包括功率开关，控制器用于输出第一控制信号给n个功率变换模块，以使n个功率变换模块同步工作，根据同步工作的n个功率变换模块中序号相同的功率开关两端的电压震荡频率，确定n个功率变换模块所对应的移相角，根据n个功率变换模块所对应的移相角输出第二控制信号给n个功率变换模块，以使n个功率变换模块错相工作。本申请功率变换装置及其控制方法、电源系统能够在不增加硬件成本的情况下有效抑制功率开关两端。

Description

功率变换装置及其控制方法、电源系统
本申请要求于2022年10月10日提交中国专利局、申请号为202211237046.6，发明名称为“功率变换装置及其控制方法、电源系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电路技术领域，尤其涉及一种功率变换装置及其控制方法、电源系统。
背景技术
随着电力电子变换技术的发展，电源系统在功率变换能力、转换效率、功率开关应力等方面的参数要求不断提高。将多个功率变换模块的输入及输出并联，每个功率变换模块提供整个电源系统功率的一部分，可以降低每个功率变换模块中的功率开关的应力。
然而，每个功率变换模块中的器件、电路布局以及电路走线等存在有寄生电感、寄生电容等寄生参数。当功率变换模块中的功率开关高频动作时，寄生参数容易发生谐振，导致功率开关两端的电压产生不可避免的电压震荡。电压震荡会造成功率开关电压应力提高，功率开关存在过压失效的风险。而且，输入并联输出并联(Input-Parallel Output-Parallel，IPOP)的电路拓扑结构需增加功率开关的数量，使得电路的寄生参数更加复杂。当多个功率变换模块同步工作时，更多数量的功率开关同时高频动作，这就导致电压震荡问题更加显著，功率开关的应力风险也更大。
发明内容
有鉴于此，本申请提供一种功率变换装置及其控制方法、电源系统，能够在不增加硬件成本的情况下有效抑制功率开关两端的电压震荡，减小功率开关的电压应力，提升功率变换装置及电源系统工作的安全性和稳定性。
第一方面，本申请提供一种功率变换装置，该功率变换装置包括控制器和n个功率变换模块，n为大于1的正整数，n个功率变换模块并联，控制器电连接每个功率变换模块，每个功率变换模块均包括功率开关，控制器用于输出第一控制信号给n个功率变换模块，以控制n个功率变换模块同步工作，根据同步工作的n个功率变换模块中序号相同的功率开关两端的电压震荡频率，确定n个功率变换模块所对应的移相角，再根据n个功率变换模块所对应的移相角输出第二控制信号给n个功率变换模块，以控制n个功率变换模块错相工作。
可以理解，n个功率变换模块错相工作，意味着n个功率变换模块的电路电流不同步，基于此，在功率变换模块中的寄生电感因为续流效应而对功率开关充电的情况下，寄生电感的续流情况也不会同步，如此，可以缓解多个功率变换模块的寄生电感的续流效应的叠加，而且，也使得n个功率变换模块中位置相同的功率开关两端的电压震荡不同步。进而，在不同功率变换模块中位置相同的功率开关两端的电压震荡叠加时，不同功率变换模块的电压震荡可以进行抵消，使得每一功率变换模块的电压震荡得到有效抑制，尖峰电压减小，从而有利于功率变换模块中的功率开关的电压应力的稳定及减小。由此可见，本申请提供的功率变换装置能够在不增加硬件成本的情况下有效抑制功率开关两端的电压震荡，减小及 稳定功率开关的电压应力，提升功率变换装置工作的安全性和稳定性，提高功率变换装置的产品竞争力。
在一种可能的实现方式中，控制器用于在n个功率变换模块同步工作时，获取n个功率变换模块中的全部功率开关两端的电压震荡频率，根据n个功率变换模块中相同序号的功率开关两端的电压震荡频率，确定相同序号的多个功率开关所对应的移相角，相同序号的多个功率开关所对应的移相角用于表征相同序号的多个功率开关依次发生动作的时间间隔。如此，n个功率变换模块中相同序号的多个功率开关所对应的移相角可构成n个功率变换模块所对应的移相角。
在一种可能的实现方式中，控制器用于根据相同序号的多个功率开关所对应的移相角，对相同序号的多个功率开关所对应的第一控制信号进行移相，以产生第二控制信号给n个功率变换模块，其中，相同序号的多个功率开关所对应的第二控制信号在相位上依次相差对应的移相角。如此，在对应的第二控制信号的控制下，相同序号的多个功率开关可以依次动作，由此实现错相动作。
在一种可能的实现方式中，相同序号的多个功率开关所对应的第二控制信号在相位上依次相差的移相角可以相同。如此，在对应的第二控制信号的控制下，相同序号的多个功率开关可以以相同的时间间隔依次动作。另外，移相角相同也有利于减小控制器的计算量，提高控制器的信号处理效率。当然，相同序号的多个功率开关所对应的第二控制信号在相位上依次相差的移相角也可以不同。如此，在对应的第二控制信号的控制下，相同序号的多个功率开关可以以不同的时间间隔依次动作。另外，移相角不同也更便于控制器对功率变换模块的灵活控制，更容易提升电压震荡抑制效果。
在一种可能的实现方式中，n个功率变换模块中不同序号的功率开关所对应的移相角可以相同。基于这样的实现方式，可以实现一个功率变换模块的整体移相，即，实现模块级别的移相。当然，n个功率变换模块中不同序号的功率开关所对应的移相角也可以不同。基于这样的实现方式，可以实现一个功率变换模块中的各个功率开关的独立移相，即，实现器件级别的移相。
在一种可能的实现方式中，移相角的计算公式为：
式中，αi为移相角，i为功率开关在功率变换模块中的序号；Tos为该功率开关两端的电压震荡频率；k为移相角调整系数，0≤k≤1。如此，控制器可以通过如上计算公式确定相同序号的功率开关所对应的移相角。
在一种可能的实现方式中，控制器用于对计算出的移相角αi进行微调，以获得更多移相角，使得n个功率变换模块的移相控制更加灵活。
在一种可能的实现方式中，n个功率变换模块中的每一个功率变换模块为直流-直流变换模块、交流-交流变换模块、直流-交流变换模块、交流-直流变换模块中的任意一种。基于这样的实现方式，可使得本申请功率变换装置可以灵活应用于直流-直流变换、交流-交流变换、直流-交流变换、交流-直流变换中的任意一种场景，适用范围非常广泛。
第二方面，本申请提供一种功率变换装置的控制方法，一种功率变换装置的控制方法，其中功率变换装置包括控制器和n个功率变换模块，n为大于1的正整数，n个功率变换模块并联，控制器电连接n个功率变换模块中的每个功率变换模块，每个功率变换模块均包括功率开关，控制方法包括输出第一控制信号给n个功率变换模块，以使n个功率变换模块在第一控制信号的控制下同步工作，然后根据同步工作的n个功率变换模块中序号相同的功率开关两端的电压震荡频率，确定n个功率变换模块所对应的移相角，再根据n个功率变换模块所对应的移相角输出第二控制信号给n个功率变换模块，以使n个功率变换模块在第二控制信号的控制下错相工作。
基于这样的设计，n个功率变换模块的电路电流可以不同步，基于此，可以缓解多个功率变换模块的寄生电感的续流效应的叠加，而且，也使得n个功率变换模块中位置相同的功率开关两端的电压震荡不同步。进而，不同功率变换模块的电压震荡可以相叠加而进行抵消，使得每一功率变换模块的电压震荡得到有效抑制，尖峰电压减小，从而有利于功率变换模块中的功率开关的电压应力的稳定及减小。因此，在不增加硬件成本的情况下，本申请提供的控制方法可以有效抑制功率开关两端的电压震荡，减小功率开关的电压应力，提升功率变换装置工作的安全性和稳定性。
在一种可能的实现方式中，控制方法在确定n个功率变换模块所对应的移相角时，具体是在n个功率变换模块同步工作时，获取n个功率变换模块中的全部功率开关两端的电压震荡频率，然后根据n个功率变换模块中相同序号的功率开关两端的电压震荡频率，确定相同序号的多个功率开关所对应的移相角，其中，相同序号的多个功率开关所对应的移相角用于表征相同序号的多个功率开关依次发生动作的时间间隔。如此，n个功率变换模块中相同序号的多个功率开关所对应的移相角可构成n个功率变换模块所对应的移相角。
在一种可能的实现方式中，控制方法可以根据相同序号的多个功率开关所对应的移相角，对相同序号的多个功率开关所对应的第一控制信号进行移相，以产生第二控制信号给n个功率变换模块，其中，相同序号的多个功率开关所对应的第二控制信号在相位上依次相差对应的移相角。如此，在对应的第二控制信号的控制下，相同序号的多个功率开关可以依次动作，由此实现错相动作。
在一种可能的实现方式中，移相角的计算公式为：
式中，αi为移相角，i为功率开关在功率变换模块中的序号；Tos为该功率开关两端的电压震荡频率；k为移相角调整系数，0≤k≤1。如此，方法可以通过如上计算公式确定功率开关所对应的移相角。
第三方面，本申请提供一种电源系统，用于为用电设备供电，电源系统包括电源和功率变换装置，功率变换装置电连接于电源和用电设备之间，其中，功率变换装置包括控制器和n个功率变换模块，n为大于1的正整数，n个功率变换模块并联，控制器电连接n个功率变换模块，并用于控制n个功率变换模块错相工作，以此来抑制n个功率变换模块中的功率开关两端的电压震荡，减小功率开关的电压应力，提升电源系统工作的安全性和稳定性。
另外，第二方面和第三方面中任一种可能的实现方式所带来的技术效果可参见第一方面中不同实现方式所带来的技术效果，此处不再赘述。
附图说明
图1是多个功率变换模块同步工作时功率开关两端的电压震荡的示意图。
图2是本申请实施例提供的功率变换装置的示意图。
图3是图2中的功率变换模块并联的一种实施方式的电路图。
图4是图3中的2个功率变换模块并联的一种实施方式的电路图。
图5是图4中的2个功率变换模块的控制信号的时序图。
图6是图4中的2个功率变换模块错相工作时功率开关两端的电压震荡的示意图。
图7是图4中的2个功率变换模块错相工作时电感单元的电流的示意图。
图8为本申请实施例提供的功率变换装置的控制方法的流程图。
图9为本申请实施例提供的电源系统的示意图。
主要元件符号说明
功率变换装置                               100，100a
功率变换模块                               1，1a，1b
开关单元                                   11
电感单元                                   12，12a，12b
控制器                                     2
滤波单元                                   3
电源系统                                   1000
电源                                       200
用电设备                                   300
如下具体实施方式将结合上述附图进一步说明本申请。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述。
可理解的，本申请中所描述的连接关系指的是直接或间接连接。例如，A与B连接，既可以是A与B直接连接，也可以是A与B之间通过一个或多个其它电学元器件间接连接，例如可以是A与C直接连接，C与B直接连接，从而使得A与B之间通过C实现了连接。还可理解的，本申请中所描述的“A连接B”可以是A与B直接连接，也可以是A与B通过一个或多个其它电学元器件间接连接。
在本申请的描述中，除非另有说明，“/”表示“或”的意思，例如，A/B可以表示A或B。本文中的“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。
在本申请的描述中，“第一”、“第二”等字样仅用于区别不同对象，并不对数量和执行次序进行限定，并且“第一”、“第二”等字样也并不限定一定不同。此外，术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。
随着电力电子变换技术的发展，电源系统在功率变换能力、转换效率、功率开关应力等方面的参数要求不断提高。将多个功率变换模块的输入及输出并联，每个功率变换模块提供整个电源系统功率的一部分，可以降低每个功率变换模块中的功率开关的应力。
然而，每个功率变换模块中的器件、电路布局以及电路走线等存在有寄生电感、寄生电容等寄生参数。当一个功率变换模块中的功率开关切换通断状态时，电路电流会发生变化，引起寄生参数发生谐振。具体来说，寄生电感会因为续流效应而在功率开关切换状态瞬间持续对功率开关充电，这就使得寄生电容得以充电储能，寄生电容充电结束后又释放电能给寄生电感储能，如此循环往复。并且，寄生参数传输的电能在循环的充放电过程中会逐渐消耗。这就导致功率开关两端的电压出现电压震荡现象，对应地，如图1所示，功率开关两端的电压波形发生衰减性的波动，产生若干个波峰和波谷。其中，波峰时的电压为波峰电压，波谷时的电压为波谷电压。第一个波峰的电压最大，该电压即为尖峰电压。可以理解，功率开关两端的电压发生震荡，即代表功率开关的电压应力发生震荡，电压应力不稳定。并且，尖峰电压会使得功率开关电压应力提高，导致功率开关存在过压失效的风险。当多个功率变换模块同步工作时，寄生电感的续流效应叠加，导致功率开关两端的电压震荡更为剧烈，尖峰电压更大，功率开关过应力的风险进一步增大。
因此，本申请的实施例提供一种功率变换装置及其控制方法、电源系统，可以在不增加硬件的情况 下有效抑制功率开关两端的电压震荡，减小功率开关的电压应力，并使功率开关的电压应力稳定，由此提升功率变换装置及电源系统工作的安全性和稳定性。
下面结合附图来对本申请的技术方案作进一步的详细描述。
请参阅图2，图2所示为本申请的一个实施例提供的一种功率变换装置100的结构示意图。
如图2所示，功率变换装置100包括n个功率变换模块1和控制器2。其中，n为大于1的正整数。n个功率变换模块1并联。即，n个功率变换模块1的输入侧并联连接，n个功率变换模块1的输出侧也并联连接，从而形成输入并联输出并联(Input-Parallel Output-Parallel，IPOP)的结构。
可以理解，在本申请的实施方式中，n个功率变换模块1均采用相同的电路，如此可以避免因为电路不同而导致部分功率变换模块1承担较大的功率，进而导致器件过应力，引起器件的损坏。
可以理解，每个功率变换模块1均包括m个功率开关，m为正整数。功率变换模块1可通过m个功率开关的导通或关断来改变电压，以此实现电压转换功能。
其中，功率变换模块1的功率开关可以为金属氧化物半导体场效应晶体管(metal-oxide-semiconductor field-effect transistor，MOSFET)、绝缘栅型双极性晶体管(insulated gate bipolar transistor，IGBT)、由多个MOSFET并联或串联而成的开关电路、多个IGBT并联或串联而成的开关电路、由MOSFET与反接的二极管并联而成的开关电路、或由IGBT与反接的二极管并联而成的开关电路，在此不做具体限定。为描述方便，本申请实施例以功率开关为MOSFET与反接的二极管并联而成的开关电路为例进行说明。
可以理解，m个功率开关可以采用内部参数一致的器件，以减小杂质电感和分布电容。m个功率开关的栅极可用于接收控制信号，以在控制信号的控制下导通和关断。示例的，功率开关可以在接收到控制信号中的高电平时导通，在接收到控制信号中的低电平时关断。其中，可以理解，功率开关的导通和关断是指功率开关中的开关器件的导通和关断。
请参阅图3，图3为单个功率变换模块1的一种实施方式的电路图。如图3所示，每个功率变换模块1包括开关单元11和电感单元12。
开关单元11包括四个功率开关Q1～Q4。电感单元12包括电感L1。功率开关Q1的源极连接功率开关Q2的漏极。功率开关Q3的源极连接功率开关Q4的漏极。功率开关Q2的源极连接功率开关Q4的源极。电感L1的一端连接至功率开关Q1的源极与功率开关Q2的漏极之间，电感L1的另一端连接至功率开关Q3的源极与功率开关Q4的漏极之间。
可以理解，上述功率变换模块1可构成降压-升压(BUCK-BOOST)电路。具体地，功率变换模块1工作时，功率开关Q1和Q2互补导通，功率开关Q3和Q4互补导通。电感L1在上述功率开关Q1～Q4的通断过程中进行能量的存储及释放，从而使得功率变换模块1实现升压/降压功能。其中，功率变换模块1可以通过调整功率开关的通断时长以改变电感L1存储的能量大小，进而实现升压/降压功能。
可以理解，在一些实施方式中，如图3所示，n个功率变换模块1的输入侧并联后再电连接至同一个滤波单元3。同样，n个功率变换模块1的输出侧也可以并联后再电连接至另一个滤波单元3。当然，在另一些实施方式中，也可以是n个功率变换模块1的输入侧和输出侧分别并联对应的一个滤波单元3。其中，可以理解，每个滤波单元3可以包括至少一个电容，也均可以包括相连接的至少一个电容和至少一个电阻，在此不做具体限定。两个滤波单元3可用于对相连接的功率变换模块1两侧的电压进行滤波处理。
可以理解，上述图3所示的实施方式中，开关单元11和电感单元12共同形成H桥拓扑结构。其中，功率开关Q1的漏极及功率开关Q2的源极形成H桥拓扑的其中一侧。功率开关Q3的漏极及功率开 关Q4的源极形成H桥拓扑的另一侧。而每个功率变换模块1可以以H桥拓扑两侧中的任意一侧作为输入侧，另一侧作为输出侧，因此，每个功率变换模块1均为双向功率变换模块，可以实现能量双向传递。基于此，功率变换装置100可以应用于双向能量传递的应用场合。
当然，本申请实施例中的每个功率变换模块1还可以采用其他拓扑结构的双向功率变换模块。例如，在一些实施例中，功率变换模块1还可形成全桥拓扑结构。对应地，功率变换模块1为双向LLC谐振全桥电路。又例如，在其他一些实施例中，功率变换模块1还可形成半桥拓扑结构。对应地，功率变换模块1为双向LLC谐振半桥电路。也就是说，在本申请实施例中，并不对功率变换模块1的拓扑结构进行限定，只需确保功率变换模块1具有功率开关，且可以通过功率开关的导通和关断来实现电压转换功能即可。
可以理解，在其他一些实施方式中，每个功率变换模块1也可以为可实现能量单向传递的单向功率变换模块，例如可以为降压(BUCK)变换器、升压(BOOST)变换器等。基于此，功率变换装置100可以应用于单向能量传递的应用场合。
可以理解，上述图3所示的实施方式中，功率变换模块1为直流-直流变换模块。在其他实施方式中，功率变换模块1也可以采用直流-交流变换模块、交流-直流变换模块和交流-交流变换模块中的任意一种，在此不做具体限定。
可以理解，上述图3所示的实施方式中，功率变换模块1为单个功率变换器。在其他实施方式中，功率变换模块1也可以由串联、并联或串并联的多个功率变换器组成，在此不做具体限定。
请继续参阅图2，控制器2电连接n个功率变换模块1，可用于控制n个功率变换模块1的电压转换。
可以理解，控制器2可以是通用中央处理器(CPU)、微处理器、特定应用集成电路(application-specific integrated circuit，ASIC)、或一个或多个用于控制以上方案程序执行的集成电路。
可以理解，控制器2可以基于脉冲宽度调制(Pulse Width Modulation，PWM)方式、脉冲频率调节(Pulse Frequency Modulation，PFM)方式、PWM和PFM混合的方式或者其他方式来产生控制信号给n个功率变换模块1中的每个功率开关，以控制每个功率开关的通断状态，进而控制n个功率变换模块1的工作过程。
另外，控制器2还用于对n个功率变换模块1进行移相控制，以使得n个功率变换模块1可以错相工作，进而有效抑制n个功率变换模块1中的功率开关两端的电压震荡，减小功率开关的电压应力震荡幅度。
以下为描述方便，以两个功率变换模块1a、1b(即n＝2)，且两个功率变换模块1a、1b均为图3所示的H形拓扑结构为例，详细介绍控制器2对两个功率变换模块1a、1b进行移相控制的过程。
如图4所示，功率变换模块1a具有四个功率开关Q1～Q4和电感单元12a(也即电感L1)，功率变换模块1b具有四个功率开关为Q1’～Q4’和电感单元12b(也即电感L1’)。其中，功率开关Q1和Q1’在功率变换模块中的序号及位置相同，功率开关Q2和Q2’在功率变换模块中的序号及位置相同，功率开关Q3和Q3’在功率变换模块中的序号及位置相同，功率开关Q4和Q4’在功率变换模块中的序号及位置相同。
控制器2用于产生第一控制信号给功率变换模块1a和1b，以控制功率变换模块1a和1b同步工作。
可以理解，同步工作是指不同功率变换模块的工作情况一致，例如，当功率变换模块1a启动时，功率变换模块1b也同时启动。换句话说，同步工作可理解为不同功率变换模块所对应的第一控制信号相位一致，因此，同步工作也可称为同相工作。而与同步工作相对应的，不同步工作是指不同功率变换模块的工作情况不一致，例如，功率变换模块1a先启动，功率变换模块1b后启动。也即，功率变换模块1a和功率变换模块1b所对应控制信号之间存在相位差，因此，不同步工作也可称为错相工作。
因此，在第一控制信号的控制下，功率开关Q1和Q1’同步动作，功率开关Q2和Q2’同步动作，功率开关Q3和Q3’同步动作，功率开关Q4和Q4’同步动作。功率开关Q1和Q2互补导通，功率开关Q3和Q4互补导通。
接着，请参阅图5，第一控制信号用实线表示。
如图5所示，在t1至t2时段，功率开关Q1和Q1’、Q4和Q4’的第一控制信号为低电平，故功率开关Q1和Q1’、Q4和Q4’处于关断状态。功率开关Q2和Q2’、Q3和Q3’的第一控制信号为高电平，故功率开关Q2和Q2’、Q3和Q3’处于导通状态。
在t2时刻，功率开关Q1和Q1’的第一控制信号跳变为高电平，故功率开关Q1和Q1’从关断状态切换为导通状态。功率开关Q2和Q2’的第一控制信号跳变为低电平，故功率开关Q2和Q2’从导通状态切换为关断状态。功率开关Q3和Q3’、Q4和Q4’的第一控制信号的电平保持不变，故功率开关Q3和Q3’保持导通，Q4和Q4’保持关断。
在t2至t3时段，功率开关Q1和Q1’、Q3和Q3’保持导通，功率开关Q2和Q2’、Q4和Q4’保持关断。
在t3时刻，功率开关Q1和Q1’、Q2和Q2’的第一控制信号的电平保持不变，故功率开关Q1和Q1’保持导通，Q2和Q2’保持关断。功率开关Q4和Q4’的第一控制信号跳变为高电平，故功率开关Q4和Q4’从关断状态切换为导通状态。功率开关Q3和Q3’的第一控制信号跳变为低电平，故功率开关Q3和Q3’从导通状态切换为关断状态。
在t3至t4时段，功率开关Q1和Q1’、Q4和Q4’保持导通，功率开关Q2和Q2’、Q3和Q3’保持关断。
在t4时刻，功率开关Q1和Q1’、Q2和Q2’的第一控制信号的电平保持不变，故功率开关Q1和Q1’保持导通，Q2和Q2’保持关断。功率开关Q3和Q3’的第一控制信号跳变为高电平，故功率开关Q3和Q3’从关断状态切换为导通状态。功率开关Q4和Q4’的第一控制信号跳变为低电平，故功率开关Q4和Q4’从导通状态切换为关断状态。
在t4至t5时段，功率开关Q1和Q1’、Q3和Q3’保持导通，功率开关Q2和Q2’、Q4和Q4’保持关断。
可以理解，在上述过程中，功率开关Q1～Q4及Q1’～Q4’中一旦有功率开关发生动作，功率变换模块1a、1b的电路电流会发生变化，进而引起发生动作的功率开关两端(即漏源极)发生电压震荡。而由于上述过程中，功率开关Q1～Q4及Q1’～Q4’均有发生动作。因此，经过上述过程，控制器2可获取到功率开关Q1～Q4、Q1’～Q4’两端的电压震荡频率。
其中，可以理解，由于功率开关Q1和Q1’的内部参数一致，在对应的功率变换模块中的位置相同，并且同步动作，因此，功率开关Q1两端的电压震荡频率等同于功率开关Q1’两端的电压震荡频率。所以，当获取功率开关Q1两端的电压震荡频率时，也即获取到功率开关Q1’两端的电压震荡频率。功率开关Q2和Q2’、Q3和Q3’、Q4和Q4’同理，在此不再赘述。
另外，可以理解，由于功率变换模块1a中，功率开关Q1和Q2串联并形成H桥拓扑的一侧，功率开关Q3和Q4串联并形成H桥拓扑的另一侧，并且，功率开关Q1和Q2状态互补，功率开关Q3和Q4状态互补。因此，当功率开关Q1发生动作时，功率开关Q1两端的电压震荡频率等同于功率开关Q1和Q2所形成的H桥拓扑一侧处的电压震荡频率。所以，当获取到功率开关Q1所在的H桥拓扑一侧处的电压震荡频率时，也即获取到功率开关Q1两端的电压震荡频率。功率开关Q2～Q4、功率变换模块1b中的Q1’～Q4’同理，故不再赘述。
在获取到功率开关Q1～Q4、Q1’～Q4’两端的电压震荡频率后，控制器2还用于根据这些电压震荡频率 确定功率变换模块1a和1b所对应的移相角。
可以理解，功率变换模块1a和1b所对应的移相角由功率变换模块1a和1b中相同序号的功率开关所对应的移相角构成，因此，功率变换模块1a和1b所对应的移相角包括功率开关Q1和Q1’所对应的移相角α1，功率开关Q2和Q2’所对应的移相角α2，功率开关Q3和Q3’所对应的移相角α3，以及功率开关Q4和Q4’所对应的移相角α4。移相角用于表征相同序号的多个功率开关依次发生动作的时间间隔。
在本申请实施例中，控制器2可按照如下计算公式确定移相角：
式中，i为功率开关在功率变换模块1中对应的序号。例如，以图4所示的功率变换模块1a、1b包括四个功率开关为例，i为1、2、3或4。对应地，αi则代表序号同为i的多个功率开关所对应的移相角。
Tos为对应的功率开关两端的电压震荡频率。k为移相角调整系数，-1≤k≤1。
其中，当k＝0时，移相角为0，说明相同序号的多个功率开关同步动作。
当0<k≤1时，说明相同序号的多个功率开关以对应的移相角作为时间间隔依次滞后动作。
当-1≤k<0时，说明相同序号的多个功率开关以对应的移相角作为时间间隔依次超前动作。
可以理解，在确定出移相角后，控制器2还用于根据功率变换模块1a和1b所对应的移相角对功率变换模块1a和1b进行移相控制。
具体地，控制器2用于根据功率变换模块1a和1b中相同序号的多个功率开关所对应的移相角，对对应的相同序号的多个功率开关的第一控制信号进行移相，以产生第二控制信号。其中，相同序号的多个功率开关所对应的第二控制信号在相位上依次相差移相角。
例如，以图3所示的功率变换装置为例，假设功率变换装置中的功率变换模块按照从上到下顺序排序，则第一个功率变换模块与第二个功率变换模块中的功率开关Q1所对应的第二控制信号在相位上相差移相角，第二个功率变换模块与第三个功率变换模块中的功率开关Q1所对应的第二控制信号在相位上也相差移相角，以此类推。
如此，在对应的第二控制信号的控制下，功率变换装置中相同序号的多个功率开关可以错相动作。
其中，可以理解，相同序号的多个功率开关中每两个功率开关所对应的移相角可以相同。当然，在实际控制过程中，相同序号的多个功率开关中每两个功率开关所对应的移相角还可以根据实际情况进行微调，因此，相同序号的多个功率开关中每两个功率开关所对应的移相角也可以不同。
其中，可以理解，在一些情况下，可以是相同序号的多个功率开关的第一控制信号均进行移相，移相可以是令第二控制信号的相位超前，也可以是令第二控制信号的相位滞后，只要确保相同序号的多个功率开关的第二控制信号在相位上依次相差移相角即可。
当然，在另一些情况下，也可以是其中一个功率开关的第一控制信号未移相，其他功率开关的第一控制信号均进行移相。
例如，请再次参阅图5，功率变换模块1a中的功率开关Q1～Q4所对应第一控制信号移动的相位为0，而功率变换模块1b中的功率开关Q1’～Q4’所对应的第一控制信号均移相。因此，参见图5中的实线，功率开关Q1～Q4的第二控制信号与功率开关Q1～Q4的第一控制信号相同。功率开关Q1’～Q4’的第二控制信号可参见图5中的虚线，功率开关Q1’～Q4’的第二控制信号与功率开关Q1～Q4的第二控制信号存在相位差。
其中，功率开关Q1’的第二控制信号以移相角α1滞后于功率开关Q1的第二控制信号。
功率开关Q2’的第二控制信号以移相角α2滞后于功率开关Q2的第二控制信号。
功率开关Q3’的第二控制信号以移相角α3滞后于功率开关Q3的第二控制信号。
功率开关Q4’的第二控制信号以移相角α4滞后于功率开关Q4的第二控制信号。
如此，在t2时刻，功率开关Q1的第二控制信号跳变为高电平，故功率开关Q1从关断状态切换为导通状态。功率开关Q2的第二控制信号跳变为低电平，故功率开关Q2从导通状态切换为关断状态。而功率开关Q1’和Q2’的第二控制信号的电平保持不变，故功率开关Q1’保持关断，Q2’保持导通。功率开关Q3和Q3’、Q4和Q4’的第二控制信号的电平保持不变，故功率开关Q3和Q3’保持导通，Q4和Q4’保持关断。
在t2’时刻，功率开关Q1’的第二控制信号才跳变为高电平，功率开关Q2’的第二控制信号才跳变为低电平，使得功率开关Q1’从关断状态切换为导通状态，功率开关Q2’从导通状态切换为关断状态。功率开关Q3和Q3’仍然保持导通，Q4和Q4’仍然保持关断。
在t3时刻，功率开关Q3的第二控制信号跳变为低电平，故功率开关Q2从导通状态切换为关断状态。功率开关Q4的第二控制信号跳变为高电平，故功率开关Q4从关断状态切换为导通状态。而Q3’的第二控制信号保持原来的高电平，功率开关Q4’的第二控制信号保持原来的低电平，故功率开关Q3’、Q4’未发生动作。功率开关Q1和Q1’、Q2和Q2’的第二控制信号的电平保持不变，故功率开关Q1和Q1’保持导通，Q2和Q2’保持关断。
在t4’时刻，Q3’的第二控制信号才跳变为低电平，功率开关Q4’的第二控制信号才跳变为高电平，使得功率开关Q3’从导通状态切换为关断状态，功率开关Q4’从关断状态切换为导通状态。功率开关Q1和Q1’仍然保持导通，Q2和Q2’仍然保持关断。
可以理解，四个移相角α1～α4可以表示为如下矩阵A：
其中，在一些实施例中，移相角α1～α4相等，相当于是控制器2对功率变换模块1a和1b的全部功率开关所对应的第一控制信号进行整体的移相。因此，这种情况可理解为是模块级别的移相。
当然，在其他实施例中，移相角α1～α4也可以不相等。可以理解，移相角α1～α4不相等，相当于是控制器2对两个功率变换模块1a和1b的四个功率开关所对应的第一控制信号各自独立移相。因此，这种情况可理解为是器件级别的移相。
如上所述，在第二控制信号的控制下，功率变换模块1a和1b中相同序号功率开关Q1和Q1’、Q2和Q2’、Q3和Q3’、Q4和Q4’均错相动作，因此，功率变换模块1a和1b即实现错相工作。
可以理解，由于功率变换模块1中的功率开关动作时，功率变换模块1的电路电流会随着功率开关的动作而发生变化。例如，以图4所示的功率变换模块1a、1b为例，电感单元12a的电流会随着功率开关Q1～Q4的动作而变化，电感单元12b的电流会随着功率开关Q1’～Q4’的动作而变化。
因此，当功率开关Q1’～Q4’在第二控制信号的控制下滞后于功率开关Q1～Q4发生动作时，电感单元12b的电流也会滞后于电感单元12a的电流。即，电感单元12a的电流和12b的电流会错相。例如，请参阅图6，电感单元12a的电流波形用实线表示，电感单元12b的电流波形用虚点线表示。在功率开关Q1’～Q4’均以移相角α1(即α1＝α2＝α3＝α4)滞后于功率开关Q1～Q4发生动作时，电感单元12b的电流波形以移相角α1滞后于功率变换模块1a中的电感单元12a的电流波形。
对应地，在功率变换模块1a、1b中的寄生电感因为续流效应而对功率开关充电，进而引起功率开关两端的电压震荡的情况下，由于功率变换模块1a、1b中的电路电流错相，电流变化不同步，因此，寄生电感的续流情况也不会同步，这使得功率开关Q1和Q1’、Q2和Q2’、Q3和Q3’、Q4和Q4’两端的电压震荡也不会同步。
为方便理解，以功率开关Q1和Q1’为例进行说明。请参阅图7，由于功率开关Q1在t2时刻发生动作，功率开关Q1’是在t2’时刻发生动作，因此，功率开关Q1两端的电压先产生电压震荡，功率开关Q1’两端的电压后产生电压震荡。对应地，功率开关Q1’两端电压所对应的电压波形(参见图7中的虚线)滞后于功率开关Q1两端电压所对应的电压波形(参见图7中的虚点线)。
基于此，在功率开关Q1所对应电压波形在达到第一个波峰之后，功率开关Q1’所对应电压波形才会开始上升至第一个波峰。也即是说，功率开关Q1’所对应电压波形是在功率开关Q1所对应电压波形从尖峰电压下降的期间才开始上升至尖峰电压。
在这种情况下，两个功率开关Q1和Q1’所对应电压波形中有至少一部分波峰和至少一部分波谷可以实现相对应。即，同一时刻下，功率开关Q1有至少一部分波峰电压与功率开关Q1’的至少一部分波谷电压可以相对应，功率开关Q1有至少一部分波谷电压与功率开关Q1’的至少一部分波峰电压可以相对应。
而波峰电压和波谷电压叠加后会相抵消，因此，在两个功率开关Q1和Q1’所对应电压波形中有至少一部分波峰和至少一部分波谷相对应的情况下，相对应的波峰电压和波谷电压可以叠加而相抵消，从而，功率开关Q1和Q1’两端的电压震荡幅度可以变小，电压震荡得以有效抑制。因此，功率开关Q1所对应电压波形(参见图7中的实线)和功率开关Q1’所对应电压波形变得平缓，波动幅度变小。
由此可见，功率开关Q1和Q1’错相动作可以缓和功率变换模块1a、1b中寄生电感的续流效应的叠加，抑制功率开关Q1和Q1’两端的电压震荡，减小尖峰电压，从而有利于功率开关Q1和Q1’的电压应力的减小以及稳定。
同理，参照上述移相控制过程，在功率开关Q2和Q2’、Q3和Q3’、Q4和Q4’均错相动作的情况下，功率开关Q2和Q2’、Q3和Q3’、Q4和Q4’两端的电压震荡也均能得到有效抑制，功率开关Q2和Q2’、Q3和Q3’、Q4和Q4’的电压应力也可以减小且变得稳定。因此，整个功率变换模块1a和1b的全部功率开关的过应力风险可以实现降低。
进一步地，当功率变换模块1为3个以上时，控制器2可以参照上述过程对3个以上的功率变换模块1进行移相控制，以使得3个以上的功率变换模块1可以错相工作。进而，3个以上的功率变换模块1中的功率开关两端的电压震荡均可以得到有效抑制，电压应力可以减小且变得稳定。
因此，本申请实施例的功率变换装置100通过令n个功率变换模块1错相工作，可以在没有增加电路/器件的情况下减小功率开关的电压应力，并且使得电压应力变得稳定，如此可以降低功率开关过应力的风险。
请参阅图8，本申请实施例还提供一种功率变换装置的控制方法，适用于上述功率变换装置100。
如图8所示，功率变换装置的控制方法包括以下步骤：
步骤S1：控制器2输出第一控制信号给n个功率变换模块1，以使得n个功率变换模块1在第一控制信号的控制下同步工作。
其中，n为大于1的正整数。
其中，由于功率变换模块1是通过功率开关的动作来实现电压转换功能，因此，步骤S1可以具体为：
控制器2输出第一控制信号给n个功率变换模块1中相同序号的功率开关，n个功率变换模块1中相同序号的功率开关在第一控制信号的控制下同步动作，以使n个功率变换模块1同步工作。
步骤S2：控制器2根据同步工作的所述n个功率变换模块中序号相同的功率开关两端的电压震荡频率，确定n个功率变换模块1所对应的移相角。
步骤S3：控制器2根据n个功率变换模块1所对应的移相角输出第二控制信号至n个功率变换模块 1，以使n个功率变换模块1在第二控制信号的控制下错相工作。
在本申请实施例中，n个功率变换模块1所对应的移相角包括n个功率变换模块1中相同序号的多个功率开关所对应的移相角，其中，相同序号的多个功率开关所对应的移相角用于表征相同序号的多个功率开关依次发生动作的时间间隔。
因此，步骤S2可以包括以下步骤：
步骤S21：在n个功率变换模块1同步工作时，控制器2获取每个功率变换模块1中的功率开关两端的电压震荡频率。
步骤S22：控制器2根据n个功率变换模块1中相同序号的功率开关两端的电压震荡频率，确定相同序号的多个功率开关所对应的移相角。具体描述可参阅上述功率变换装置100中的相关描述，在此不再赘述。
对应地，步骤S3具体为：
控制器2根据n个功率变换模块1中相同序号的多个功率开关所对应的移相角，对对应的相同序号的多个功率开关的第一控制信号进行移相，以产生第二控制信号。其中，相同序号的多个功率开关所对应的第二控制信号在相位上依次相差移相角。
因此，在相应的第二控制信号的控制下，n个功率变换模块1中相同序号的多个功率开关以移相角作为时间间隔依次发生动作，也即是说，相同序号的多个功率开关错相动作。如此，n个功率变换模块1即实现错相工作。
可以理解，通过令n个功率变换模块1中相同序号的多个功率开关错相动作，可以使得相同序号的多个功率开关两端的电压震荡不同步，如此，相同序号的多个功率开关两端的电压应力震荡可以相抵消，功率开关两端的电压应力震荡幅度由此得以降低，电压应力得以减小，并且变得稳定，进而功率开关过应力的风险也得以降低。
请参阅图9，本申请实施例还提供一种电源系统1000。电源系统1000可用于电连接用电设备300，以为用电设备300供电。用电设备300包括但不限于通信设备、计算机、电动车辆等。
电源系统1000包括电源200和功率变换装置100a。功率变换装置100a电连接于电源200和用电设备300之间，功率变换装置100a用于获取电源200的电压，并将电源200的电压转换为用电设备300所需的电压。
可以理解，功率变换装置100a可以为上述功率变换装置100，具体可参阅图1至图7的描述，在此不再赘述。
在一些实施方式中，电源系统1000为直流电源系统。功率变换装置100a为直流-直流(Direct Current to Direct Current，DC-DC)变换装置，可用于将一种直流电压转换为另一种直流电压。
其中，可以理解，在一些情况下，电源200可以是交流-直流(Alternating Current to Direct Current，AC-DC)变换模块。AC-DC变换模块电连接功率变换装置100a，AC-DC变换模块可用于将交流电压转换为直流电压，并将直流电压输出至功率变换装置100a。
在另一些情况下，电源200也可以是电池。电池与功率变换装置100a电连接。功率变换装置100a可以从电池取电。当功率变换装置100a可实现双向能量传递时，功率变换装置100a也可以为电池供电，以使电池进行充电。
其中，可以理解，在一些情况下，电源系统1000还可以包括直流母排。直流母排与功率变换装置100a电连接。直流母排可用于电连接用电设备300，以将功率变换装置100a产生的直流电压输出至用电设备300。
在本申请各实施例中的各功能单元可以全部集成在一个处理单元中，也可以是各单元分别单独作为一个单元，也可以两个或两个以上单元集成在一个单元中；上述集成的单元既可以采用硬件的形式实现，也可以采用硬件加软件功能单元的形式实现。
本申请上述集成的单元如果以软件功能模块的形式实现并作为独立的产品销售或使用时，也可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请实施例的技术方案本质上或者说对现有技术做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机、服务器、或者网络设备等)执行本申请各个实施例所述方法的全部或部分。而前述的存储介质包括：移动存储设备、ROM、RAM、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (11)

  1. 一种功率变换装置，所述功率变换装置包括控制器和n个功率变换模块，n为大于1的正整数，所述n个功率变换模块并联，所述控制器电连接所述n个功率变换模块中的每个功率变换模块，所述每个功率变换模块均包括功率开关，其特征在于，
    所述控制器用于：
    输出第一控制信号给所述n个功率变换模块，所述第一控制信号用于控制所述n个功率变换模块同步工作；
    根据同步工作的所述n个功率变换模块中序号相同的功率开关两端的电压震荡频率，确定所述n个功率变换模块所对应的移相角；
    根据所述n个功率变换模块所对应的移相角输出第二控制信号给所述n个功率变换模块，所述第二控制信号用于控制所述n个功率变换模块错相工作。
  2. 如权利要求1所述的功率变换装置，其特征在于，所述n个功率变换模块所对应的移相角由所述n个功率变换模块中相同序号的多个功率开关所对应的移相角构成；
    所述控制器用于：
    在所述n个功率变换模块同步工作时，获取所述n个功率变换模块中的全部功率开关两端的电压震荡频率；
    根据所述n个功率变换模块中相同序号的多个功率开关两端的电压震荡频率，确定所述相同序号的多个功率开关所对应的移相角，所述相同序号的多个功率开关所对应的移相角用于表征相同序号的多个功率开关依次发生动作的时间间隔。
  3. 如权利要求2所述的功率变换装置，其特征在于，所述控制器用于：
    根据所述相同序号的多个功率开关所对应的移相角，对所述相同序号的多个功率开关所对应的第一控制信号进行移相，以产生所述第二控制信号；
    其中，所述相同序号的多个功率开关所对应的第二控制信号在相位上依次相差对应的移相角。
  4. 如权利要求3所述的功率变换装置，其特征在于，所述相同序号的多个功率开关所对应的第二控制信号在相位上依次相差的移相角相同；或者
    所述相同序号的多个功率开关所对应的第二控制信号在相位上依次相差的移相角不同。
  5. 如权利要求3所述的功率变换装置，其特征在于，所述n个功率变换模块中不同序号的功率开关所对应的移相角相同；或者
    所述n个功率变换模块中不同序号的功率开关所对应的移相角不同。
  6. 如权利要求2至5中任一项所述的功率变换装置，其特征在于，所述控制器通过如下计算公式确定所述移相角：
    式中，αi为移相角，i为所述功率开关在功率变换模块中的序号；Tos为所述功率开关两端的电压震荡频率；k为移相角调整系数，-1≤k≤1。
  7. 一种功率变换装置的控制方法，所述功率变换装置包括控制器和n个功率变换模块，n为大于1的正整数，所述n个功率变换模块并联，所述控制器电连接所述n个功率变换模块中的每个功率变换模块，所述每个功率变换模块均包括功率开关，其特征在于，
    所述控制方法包括：
    输出第一控制信号给所述n个功率变换模块，所述第一控制信号用于控制所述n个功率变换模块同步工作；
    根据同步工作的所述n个功率变换模块中序号相同的功率开关两端的电压震荡频率，确定所述n个功率变换模块所对应的移相角；
    根据所述n个功率变换模块所对应的移相角输出第二控制信号给所述n个功率变换模块，所述第二控制信号用于控制所述n个功率变换模块错相工作。
  8. 如权利要求7所述的控制方法，其特征在于，所述n个功率变换模块所对应的移相角由所述n个功率变换模块中相同序号的多个功率开关所对应的移相角构成；
    所述根据n个所述功率变换模块中相同序号的功率开关两端的电压震荡频率，确定所述n个功率变换模块所对应的移相角，包括以下步骤：
    在所述n个功率变换模块同步工作时，获取所述n个功率变换模块中的全部功率开关两端的电压震荡频率；
    根据所述n个功率变换模块中相同序号的功率开关两端的电压震荡频率，确定所述相同序号的多个功率开关所对应的移相角，所述相同序号的多个功率开关所对应的移相角用于表征相同序号的多个功率开关依次发生动作的时间间隔。
  9. 如权利要求8所述的控制方法，其特征在于，所述根据所述n个功率变换模块所对应的移相角输出第二控制信号给所述n个功率变换模块，具体为：
    根据所述相同序号的多个功率开关所对应的移相角，对所述相同序号的多个功率开关所对应的第一控制信号进行移相，以产生所述第二控制信号给所述n个功率变换模块；
    其中，所述相同序号的多个功率开关所对应的第二控制信号在相位上依次相差对应的移相角。
  10. 如权利要求7至9中任一项所述的控制方法，其特征在于，所述移相角通过如下计算公式确定：
    式中，αi为移相角，i为功率开关在功率变换模块中的序号；Tos为该功率开关两端的电压震荡频率；k为移相角调整系数，-1≤k≤1。
  11. 一种电源系统，用于为用电设备供电，其特征在于，所述电源系统包括电源和功率变换装置，所述功率变换装置电连接于所述电源和所述用电设备之间，所述功率变换装置包括控制器和n个功率变换模块，n为大于1的正整数，所述n个功率变换模块并联，所述控制器电连接所述n个功率变换模块，并用于控制所述n个功率变换模块错相工作。
PCT/CN2023/103438 2022-10-10 2023-06-28 功率变换装置及其控制方法、电源系统 WO2024078022A1 (zh)

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