WO2015027693A1 - 功率变换电路和功率变换*** - Google Patents

功率变换电路和功率变换*** Download PDF

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Publication number
WO2015027693A1
WO2015027693A1 PCT/CN2014/072557 CN2014072557W WO2015027693A1 WO 2015027693 A1 WO2015027693 A1 WO 2015027693A1 CN 2014072557 W CN2014072557 W CN 2014072557W WO 2015027693 A1 WO2015027693 A1 WO 2015027693A1
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WO
WIPO (PCT)
Prior art keywords
power conversion
terminal
conversion circuit
level bridge
phase
Prior art date
Application number
PCT/CN2014/072557
Other languages
English (en)
French (fr)
Inventor
胡炎申
刘云峰
石磊
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP14796387.0A priority Critical patent/EP2869452A4/en
Priority to JP2016515612A priority patent/JP6333362B2/ja
Priority to US14/542,302 priority patent/US9787217B2/en
Publication of WO2015027693A1 publication Critical patent/WO2015027693A1/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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/487—Neutral point clamped inverters
    • 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
    • H02M1/0043—Converters 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
    • H02M7/23—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 arranged for operation in parallel
    • 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
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/4837—Flying capacitor converters
    • 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
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/493—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode the static converters being arranged for operation in parallel
    • 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
    • H02M1/0064—Magnetic structures combining different functions, e.g. storage, filtering or transformation
    • 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
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • 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
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • 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
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels

Definitions

  • Embodiments of the present invention relate to power conversion techniques, and more particularly to a power conversion circuit and a power conversion system. Background technique
  • the dynamic and static voltage equalizing circuit is required to be high, and the output voltage has a high harmonic content, and an output filter needs to be set.
  • the proposal of a multi-level inverter circuit has made a breakthrough in solving the above problems.
  • the general structure of a multilevel inverter is that a step wave is synthesized by several level steps to approximate the sinusoidal output voltage. Due to the increase in the number of output voltage levels, the inverter reduces the harmonic content of the output waveform, and the voltage stress on the switch is reduced. There is no need for a voltage equalizing circuit. For example, the switching tube is used to assist the midpoint clamping.
  • Three-level inverter circuit, diode clamp inverter circuit and multi-level inverter mainly used in high voltage and high power motor speed regulation, reactive power compensation, active filtering and other fields.
  • Embodiments of the present invention provide a power conversion circuit and a power conversion system capable of compressing control logic of a power conversion circuit.
  • a power conversion circuit including: a first terminal and a second terminal for connecting with a direct current; a third terminal for connecting with an alternating current; and an N-way multi-level bridge arm connected in parallel Between the first terminal and the second terminal, for operating in an interleaved parallel manner, wherein the operation in the interleaved parallel mode is to operate in a phase-shifted manner, in each of the N-way multi-level bridge arms
  • An alternating current node that produces multiple levels that vary over time, with multiple levels greater than two Level
  • a coupled inductor comprising N windings coupled through a common core for forming mutually coupled inductors, wherein one end of each of the N windings is associated with one of the N multi-level bridge arms
  • the alternating current nodes of the level bridge arms are connected, and the other end of each of the N windings is connected to the third terminal, N being greater than or equal to two.
  • the common magnetic core is N cylinders connected to each other, N windings are respectively wound N cylinders, and the winding directions of the N windings are the same.
  • the number of turns of the N windings is the same.
  • the power conversion circuit of the first aspect further includes: a driving circuit, configured to generate a driving signal, and control the phase of the N-way multi-level bridge arm in a switching period of the driving signal of the power conversion circuit Work in a staggered 360/N degree.
  • the driving signal has a duty ratio that is located in a plurality of preset ranges, where the multiple preset ranges include [(nl)/N, n /N], where n [(nl)/N, n/N].
  • the multi-level bridge arm is an M-level bridge arm
  • the N-way multi-level bridge arm generates (M-1) *N+1 levels.
  • the power conversion circuit of the first aspect further includes: a filter circuit connected to the third terminal for filtering the alternating current; and a voltage dividing circuit connected to the first terminal and the second terminal Between, used to divide the DC power.
  • the multi-level bridge arm is a midpoint clamp type multi-level bridge arm, and the midpoint of the voltage dividing circuit is connected to the N-way multi-level bridge. The midpoint of the clamp of each multilevel bridge arm in the arm.
  • the filter circuit is a capacitor.
  • the multi-level bridge arm is a capacitive clamp type multi-level bridge arm.
  • the power conversion circuit is an inverter, configured to convert the direct current into the alternating current, the first terminal and the first The two terminals are input terminals, and the third terminal is an output terminal.
  • the power conversion circuit is a rectifier, configured to convert the alternating current into direct current, the third terminal As an input terminal, the first terminal and the second terminal are output terminals.
  • a three-phase power converter comprising: a three-phase power conversion circuit for performing power conversion between three-phase alternating current and direct current, wherein each phase power conversion circuit is power according to the first aspect Transform circuit.
  • the three-phase power converter of the second aspect further includes: a voltage dividing circuit connected between the first terminal and the second terminal of each phase power conversion circuit for dividing the direct current a three-phase filter circuit comprising three capacitors for filtering three-phase alternating current, one end of each of the three capacitors and the third of the one-phase power inverter circuit of the three-phase power inverter circuit The terminals are connected and the other ends of the three capacitors are connected together.
  • the other ends of the three capacitors are commonly connected to a midpoint of the voltage dividing circuit.
  • the three-phase power converter of the second aspect further includes: a first center line, configured to be connected to a center line of the power grid, where A neutral line is connected to one end where the three capacitors are connected together.
  • a power conversion system including: an M-channel power conversion circuit, configured to perform power conversion between an alternating current and a direct current, wherein each power conversion circuit in the M-channel power conversion circuit is The power conversion circuit of the aspect; the voltage dividing circuit is connected between the first terminal and the second terminal of each power conversion circuit in the M-channel power conversion circuit, and is used for dividing the direct current; the fourth terminal;
  • the coupled inductor includes M windings coupled through a common magnetic core for forming mutually coupled inductors, one end of each of the M windings and a third terminal of a power conversion circuit in the M-way power conversion circuit Connected, the other end of each of the M windings is connected to the fourth terminal; a filter circuit is connected to the fourth terminal for filtering the alternating current, M is greater than or equal to 2.
  • the filter circuit includes a capacitor coupled to the fourth terminal.
  • the N-way multi-level bridge arm in each power conversion circuit of the M-channel power conversion circuit has a phase-shifted angle of 360/ in a switching period of a driving signal of the power conversion circuit.
  • the (N*M) degree is used for interleaved parallel operation.
  • a power conversion system including: the first power conversion circuit is a power conversion circuit according to the tenth possible implementation manner of the first aspect, configured to convert direct current into alternating current;
  • the conversion circuit is a power conversion circuit according to the tenth possible implementation of the first aspect, for converting an alternating current into a direct current, wherein an output terminal of the first power conversion circuit and the second power conversion circuit The input terminals are connected, or the output terminals of the second power conversion circuit are connected to the input terminals of the first power conversion circuit.
  • the technical solution of the present invention combines a plurality of AC levels generated at the AC node of each multi-level bridge arm by an interleaved multi-way multi-level bridge arm combined with a coupled inductor, and an AC terminal connected to the coupled inductor Generate more AC levels on it. Since the multi-channel multi-level bridge arm can realize more levels of output by means of out-of-phase operation, the control logic of the power conversion circuit is compressed. DRAWINGS
  • FIG. 1 is a schematic block diagram of a power conversion circuit in accordance with an embodiment of the present invention.
  • FIG. 2 is a schematic block diagram of a power conversion circuit in accordance with another embodiment of the present invention.
  • FIG. 3 is a block diagram of a power conversion circuit in accordance with yet another embodiment of the present invention.
  • FIG. 4 is an equivalent circuit diagram of a coupled inductor in accordance with an embodiment of the present invention.
  • Figure 5A is a circuit diagram of a multi-level bridge arm in accordance with one embodiment of the present invention.
  • Figure 5B is a schematic timing diagram of drive signals for a multi-level bridge arm in accordance with one embodiment of the present invention.
  • Figure 5C is a circuit diagram of a multi-level bridge arm in accordance with another embodiment of the present invention.
  • Figure 6 is a circuit diagram of a power conversion circuit in accordance with one embodiment of the present invention.
  • Figure 7 is a schematic timing diagram of the duty cycle and output voltage of a drive signal in accordance with one embodiment of the present invention.
  • Figure 8 is a circuit diagram of a power conversion circuit in accordance with still another embodiment of the present invention.
  • FIG. 9 is a schematic block diagram of a power conversion system in accordance with one embodiment of the present invention.
  • Figure 10 is a schematic block diagram of a power conversion system in accordance with another embodiment of the present invention.
  • Figure 11 is a schematic block diagram of a three phase power converter in accordance with one embodiment of the present invention.
  • Figure 12 is a schematic block diagram of a three phase power converter in accordance with another embodiment of the present invention.
  • Figure 13 is a schematic block diagram of a three-phase power converter in accordance with yet another embodiment of the present invention.
  • Figure 14 is a schematic block diagram of a power conversion system in accordance with another embodiment of the present invention. detailed description
  • Interleaved parallel technology is an effective solution to increase the power capacity of power converters.
  • the staggered parallel scheme can easily improve the power level of the converter, reduce the input and output current ripple, improve the dynamic response of the converter, reduce the volume of the magnetic components in the circuit and realize the variable current.
  • Automatic current sharing Although it is possible to achieve a multi-level output topology by using an interleaved two-level bridge arm combined with a coupled inductor, this solution requires a filter circuit to filter the output multi-level waveform, which is not conducive to suppressing higher harmonics.
  • FIG. 1 is a schematic block diagram of a power conversion circuit 100 in accordance with an embodiment of the present invention.
  • Power change The circuit 100 includes a first terminal 110, a second terminal 120, a third terminal 130, an N-way multi-level bridge arm 140, and a coupling inductor 150.
  • the first terminal 110 and the second terminal 120 are connected to a direct current.
  • the third terminal 130 is connected to an alternating current.
  • the N-way multi-level bridge arm 140 includes: a multi-level bridge arm 1, a multi-level bridge arm 2, a multi-level bridge arm N, and is connected in parallel between the first terminal 110 and the second terminal 120, wherein the N-way multi-electricity
  • the flat arm 140 operates in an interleaved parallel manner, and the operation in the interleaved parallel mode refers to operation in a phase-shifted manner.
  • the alternating current node of each multi-level bridge arm in the N-way multi-level bridge arm 140 changes with time. Multiple levels, multiple levels greater than two levels.
  • the coupled inductor 150 includes N windings coupled through a common magnetic core for forming mutually coupled inductors, wherein one end of each of the N windings and one of the N multi-level bridge arms are respectively The alternating current nodes of the arms are connected, and the other end of each of the N windings is connected to a third terminal 130, N being greater than or equal to two.
  • the power conversion circuit 100 may be a rectifier circuit or an inverter circuit.
  • the power conversion circuit 100 when the first terminal and the second terminal are the input terminals and the third terminal is the output terminal, the power conversion circuit 100 is an inverter circuit.
  • the power conversion circuit 100 when the third terminal is the input terminal and the first terminal and the second terminal are the output terminals, the power conversion circuit 100 is a rectifier circuit.
  • the multi-level bridge arm is also called a multi-level topology, and includes a plurality of switch tubes.
  • the plurality of switch tubes can be complementarily turned on or off under the control of the driving signal, so that the multi-level bridge arm can be connected to the AC node of the multi-level bridge arm.
  • Interleaved parallel means that a plurality of multilevel bridge arms are operated in parallel, and the phases of the drive signals of the plurality of multilevel bridge arms are separated by a predetermined angle, for example, 360/N degrees.
  • the N-way multi-level bridge arm 140 can operate in a phase-shifted preset angle.
  • the phases of the drive signals of the three-way three-level bridge arms are separated by 120 degrees, and the interval between the phases of the drive signals of the five-way three-level bridge arms is 72 degrees.
  • the N windings are coupled by a magnetic core to form a coupled inductor
  • the N multi-level bridge arms are connected to the N windings of the coupled inductor such that each of the N multi-level bridge arms
  • the multiple levels generated by the multilevel bridge arms are combined into more levels by the coupled inductors.
  • a power conversion circuit including three three-level bridge arms can generate seven levels at a third terminal connected to the coupled inductor.
  • a power conversion circuit including three five-level bridge arms can generate thirteen levels at a third terminal coupled to the coupled inductor.
  • the spacing between the phases of the drive signals of two adjacent multi-level bridge arms may be the same angle, for example, 360/N degrees, or may be different angles.
  • setting the phase interval to the same angle makes the control method of the multi-level bridge arm more compact.
  • the technical solution of the present invention combines a plurality of AC levels generated at the AC node of each multi-level bridge arm by an interleaved multi-way multi-level bridge arm combined with a coupled inductor, and an AC terminal connected to the coupled inductor Generate more AC levels on it. Since the multi-channel multi-level bridge arm can realize more levels of output by means of out-of-phase operation, the control logic of the power conversion circuit is compressed.
  • the number of alternating current levels can be increased by the embodiment of the present invention, the content of higher harmonics in the alternating current is reduced, so that the higher harmonics can be effectively suppressed.
  • the multi-level bridge arm is a midpoint clamp type multi-level bridge arm or a capacitance clamp type multi-level bridge arm.
  • the multi-level bridge arm of the embodiment of the present invention is not limited to the two multi-level bridge arms, and may be, for example, a hybrid multi-level bridge arm.
  • the multi-level bridge arm is an M-level bridge arm, and the N-way multi-level bridge arm generates (M-1) *N+1 levels.
  • M-1 multi-level bridge arm
  • a multi-level bridge arm is a three-level bridge arm and an N-way multi-level bridge arm generates 2N+1 levels.
  • three three-level bridge arms generate seven levels, and five three-level bridge arms generate 13 levels.
  • the number of turns of the N windings is the same.
  • the scheme of setting the same number of turns with N windings can reduce the ripple current, thereby further suppressing higher harmonics.
  • the common magnetic core is N columns connected to each other, and N windings are divided Do not wrap N cylinders, and the winding directions of the N windings are the same.
  • the N-way multi-level bridge arms can be connected to the same-named ends of the N windings, respectively. Since the structure of such a coupled inductor can generate a leakage inductance, it is not necessary to provide an inductance in the filter circuit, thereby reducing the cost of the filter circuit.
  • the power conversion circuit 100 of FIG. 1 further includes: a driving circuit for generating a driving signal for controlling the N-way multi-level bridge arm to be phase-shifted by 360/ during a switching period of a driving signal of the power conversion circuit.
  • a driving circuit for generating a driving signal for controlling the N-way multi-level bridge arm to be phase-shifted by 360/ during a switching period of a driving signal of the power conversion circuit.
  • the N-way multi-level bridge arm can operate according to the same drive signal as the drive waveform (or pulse), except that the phase of the drive signals of the adjacent multi-level bridge arms differs by 360/N degrees.
  • the drive signal can be a Pulse Width Modulation (PWM) signal.
  • PWM Pulse Width Modulation
  • the driving signal has a duty ratio within a plurality of preset ranges, the plurality of preset ranges including [(nl)/N, n/N], where n [(nl)/N , n/N].
  • the multi-level output state of the third terminal depends on the preset range of the duty cycle. By adjusting the duty cycle of the drive signal, the level produced by each multi-level bridge arm enables more levels to be synthesized at the third terminal.
  • the power conversion circuit 200 includes a first terminal 210, a second terminal 220, a third terminal 230, an N-way multi-level bridge arm 240, and a coupled inductor 250.
  • the power conversion circuit 200 is similar to the power conversion circuit 100 of Fig. 1, and a detailed description is omitted as appropriate.
  • the power conversion circuit of FIG. 2 further includes: a voltage dividing circuit 260, a reference voltage terminal 270, and a filter circuit 280.
  • One end of the filter circuit 280 is connected to the third terminal 330, and the other end of the filter circuit 280 is connected to the reference voltage terminal 270 for filtering the alternating current.
  • the voltage dividing circuit 260 is connected between the first terminal 210 and the second terminal 220 for dividing the direct current.
  • the reference voltage terminal 270 is for receiving a reference voltage, for example, connected to a midpoint of the voltage dividing circuit 260, and the midpoint of the voltage dividing circuit can receive the reference voltage.
  • the midpoint of the voltage divider circuit 260 is also coupled to the clamp midpoint of the multilevel bridge arm.
  • the multi-level bridge arm 1, the multi-level bridge arm 2, ..., the multi-level bridge arm N respectively generate multi-level alternating currents V_l, V_2 V_N at their alternating current nodes.
  • Multi-level AC _1, V_2 V_N after coupling inductor The third terminal merges into more flat alternating current.
  • a power conversion circuit according to claim 7, wherein the multilevel bridge arm is a midpoint clamp type multilevel bridge arm, and a midpoint of the voltage dividing circuit is connected to each of the N multilevel bridge arms The midpoint of the clamp of the level bridge arm.
  • filter circuit 280 is a capacitor.
  • the embodiment of the present invention uses the leakage inductance generated by the coupled inductor and the capacitor 280 to form a filter circuit, so that it is not necessary to provide an inductance in the filter circuit, which can reduce the size and cost of the filter circuit, thereby reducing the size of the power conversion circuit and reducing the size. The cost of the power conversion circuit.
  • the filter circuit may further include an inductor.
  • the inductor (not shown) may be connected in series between the third terminal 230 and the coupled inductor 250.
  • the power conversion circuit 200 is an inverter for converting direct current into alternating current
  • the first terminal and the second terminal are input terminals, receive a direct current input
  • the third terminal is an output terminal, and outputs alternating current.
  • FIG. 3 is a schematic block diagram of a power conversion circuit 300 in accordance with yet another embodiment of the present invention.
  • the power conversion circuit 300 includes a first terminal 310, a second terminal 320, a third terminal 330, an N-way multi-level bridge arm 340, and a coupled inductor 350.
  • the power conversion circuit 300 is similar to the power conversion circuit 100 of Fig. 1, and a detailed description is omitted as appropriate.
  • the power conversion circuit of FIG. 3 further includes: a divided piezoelectric circuit 360, a reference voltage terminal 370, and a filter circuit 380.
  • One end of the filter circuit 380 is connected to the third terminal 330, and the other end of the filter circuit 380 is connected to the reference voltage terminal 370 for filtering the alternating current.
  • the voltage dividing circuit 360 is connected between the first terminal 310 and the second terminal 320 for dividing the direct current.
  • the reference voltage terminal 370 is for receiving a reference voltage, for example, connected to the midpoint of the voltage dividing circuit 360.
  • the midpoint of the voltage dividing circuit 360 is also connected to the clamp midpoint of the multilevel bridge arm. Under the control of the phase-interleaved drive signal, the AC is coupled through the inductor
  • multi-level AC power V_l, V_2 V_N is generated at the AC node of the multi-level bridge arm 1, multi-level bridge arm 2 multi-level bridge arm N, respectively.
  • the power conversion circuit 300 is a rectifier for changing the alternating current.
  • the first terminal 310 and the second terminal 320 are output terminals for outputting direct current.
  • FIG. 4 is an equivalent circuit diagram of a coupled inductor in accordance with an embodiment of the present invention.
  • the mode is interleaved in parallel, and the coupled inductor can be equivalent to the working model shown in Figure 4 in this case, where Lab, Lbc and Lea are equivalent coupling inductances and Lcm is leakage inductance.
  • V_o (V_l + V_2 + V_3) / 3
  • the coupled inductor can be combined to obtain a plurality of different level states of V_o according to different states of V_l, V_2 and V_3.
  • the input AC power can be changed to multi-level ACs V_l, V_2, and V_3.
  • each part of the core of the coupled inductor can be combined according to the magnetic flux conversion amount of the core.
  • Figure 5A is a circuit diagram of a multi-level bridge arm in accordance with one embodiment of the present invention.
  • Figure 5B is a schematic timing diagram of drive signals for a multi-level bridge arm in accordance with one embodiment of the present invention.
  • the midpoint clamp type three-level bridge arm includes first to fourth switches Q1 to Q4 and first to fourth diodes D1 to D4.
  • the first switching transistor Q1 is connected between the first terminal of the power conversion circuit and the alternating current node of the multi-level bridge arm.
  • the first diode D1 is connected in parallel with the first switching transistor Q1, and the anode of the first diode D1 is connected to the alternating current node of the multilevel bridge arm.
  • One end of the third switching transistor Q3 is connected to the alternating current node of the multi-level bridge arm.
  • the third diode D3 is connected in parallel with the third switching transistor Q3, and the anode of the third diode D3 is connected to the alternating current node of the multi-level bridge arm.
  • the midpoints of the roads are connected, and the other end of the second switching transistor Q2 is connected to the other end of the third switching transistor Q3.
  • the second diode D2 is connected in parallel with the second switching transistor Q2, and the anode of the second diode Q2 is connected to the midpoint of the voltage dividing circuit.
  • the fourth switching transistor Q4 is connected between the second terminal of the power conversion circuit and the alternating current node of the multi-level bridge arm.
  • the fourth diode D4 is connected in parallel with the fourth switching transistor Q4, and the negative terminal of the fourth diode D4 is connected to the alternating current node of the multilevel bridge arm.
  • the output voltage exhibits three levels of Vdc/2, 0, and -Vdc/2 depending on the state of the switch.
  • the three-level bridge arm of Figure 5A is only one example of a mid-point clamp type three-level bridge arm, and the mid-point clamp type three-level bridge arm may have other variations.
  • FIG. 5C is a circuit diagram of a multi-level bridge arm in accordance with another embodiment of the present invention.
  • the three-level bridge arm includes: a first switch tube Q1 to a fourth switch tube Q4, and a first connection in parallel with the first switch tube Q1 to the fourth switch tube Q4, respectively.
  • diodes D5 and D6 are diodes D5 and D6 for midpoint clamping.
  • the switching transistor of the present invention may be, but not limited to, a metal oxide semiconductor (Metal Oxide Semiconductor, MOSFET), Insulated Gate Bipolar Transistor (IGBT), Integrated Gate Commutated Thyristors (IGCT) or Silicon Controlled Rectifier (SCR) A combination of power devices or different power devices.
  • MOSFET Metal Oxide Semiconductor
  • IGBT Insulated Gate Bipolar Transistor
  • IGCT Integrated Gate Commutated Thyristors
  • SCR Silicon Controlled Rectifier
  • FIG. 6 is a circuit diagram of a power conversion circuit 600 in accordance with one embodiment of the present invention.
  • Power conversion circuit 600 is an example of the embodiment of Figure 1, Figure 2 or Figure 3.
  • the power conversion circuit is a power inverter circuit, and the power inverter circuit includes a three-way midpoint clamp type three-level bridge arm as an example. Accordingly, the number of windings of the coupled inductor is also three.
  • the power conversion circuit 600 may also include two three-level bridge arms or include more three-level bridge arms. The circuit topology of a power conversion circuit including other numbers of three-level bridge arms is similar to the circuit topology of a power conversion circuit including three-way three-level bridge arms, and will not be described herein.
  • the power conversion circuit 600 includes a DC bus (Bus) 610, a voltage dividing circuit 620, a three-way three-way bridge arm 630, a coupled inductor 640, and a filter circuit 650.
  • Bus DC bus
  • the first terminal of the power conversion circuit 600 is connected to the positive terminal (Bus_+) of the DC bus, and the second terminal is connected to the negative terminal (Bus_-) of the DC bus.
  • the voltage dividing circuit includes a first capacitor C1 and a second capacitor C2.
  • the first capacitor C1 is connected between Bus+ and the midpoint Bus_N of the voltage dividing circuit, and the second capacitor C2 is connected between Bus- and Bus_N.
  • the three-way three-level bridge arm 630 includes a three-level bridge arm A, a three-level bridge arm B, and a three-level bridge arm C.
  • the timing diagram of the circuit topology and the driving signal of each three-level bridge arm is shown in FIG. 5A and FIG. 5B, and details are not described herein again.
  • the AC nodes of each of the three-level bridge arms are respectively connected to the windings of the corresponding coupled inductors.
  • the second switching transistor Q2 and the third switch Q3 of each three-level bridge arm are connected in series between the Bus_N and the AC node of the three-level bridge arm.
  • the first switching transistor Q1 of each three-level bridge arm is connected between the Bus_+ of the DC bus and the AC node of the three-level bridge arm.
  • the fourth switching transistor Q4 of each three-level bridge arm is connected between the Bus_ of the DC bus and the AC node of the three-level bridge arm.
  • the midpoint of the clamp of each three-level bridge arm is connected to the midpoint of the voltage dividing circuit.
  • the midpoint of the voltage divider circuit receives the reference power Pressure.
  • the three windings of the coupled inductor 640 share a magnetic core, the magnetic core includes three cylinders, and the two ends of the three cylinders are respectively magnetically connected, and the three windings are respectively wound on the three cylinders and the winding directions are the same, three The three leading ends of the windings are respectively connected to the AC nodes of the three-way three-level bridge arms, and the three tail ends of the three windings are connected to the third terminal of the power conversion circuit.
  • Filter circuit 650 can be capacitor C3.
  • the capacitor C3 is connected between the third terminal of the power conversion circuit and the midpoint of the voltage dividing circuit.
  • the embodiment of the present invention is not limited thereto.
  • the filter circuit 650 may also be an LC filter circuit composed of an inductor and a capacitor or Other forms of filtering circuits. Filter circuit 650 is coupled to AC load 660.
  • filter circuit 650 is coupled to an alternating current source (not shown), i.e., filter circuit 650 receives an alternating current input.
  • Figure 7 is a schematic timing diagram of the duty cycle and output voltage of a drive signal in accordance with one embodiment of the present invention.
  • a plurality of levels and a plurality of levels can be generated at an alternating current node by setting a suitable duty ratio for a driving signal of the power conversion circuit such that the multi-way multi-level bridge arm changes with time. Combining at the coupled inductor results in more level states.
  • the drive signal of the power conversion circuit can be set to have different duty ratios D in different power frequency periods. For example, in the case of a three-way three-level bridge arm, the duty cycle can be set to E 1/3, l/3 ⁇ D ⁇ 2/3, 2/3 ⁇ D ⁇ 1, so that seven levels can be obtained. status.
  • V_o (V_l+V_2+V_3)/3, according to the different level states of V_l, V_2 and V_3 with time, can be in the positive half cycle and the negative half cycle of the power frequency cycle of the driving signal.
  • the different output voltages V_o of the power conversion circuit are obtained, as shown in Table 2.
  • V_o varies with the output voltage of different three-level bridge arms under different duty cycles. Duty cycle ⁇ Dog state V_l V_2 V_3 V_o
  • the output voltage V_o of the power converter varies according to the different states of the duty cycle over the entire power frequency cycle, as shown in Table 2, in the positive half cycle, if the duty cycle state (or range of variation) is 2/3 D l , then _0 is Vbus/2, and in the negative half cycle, if the duty cycle state is 2/3 D ⁇ 1, V_o is -Vbus/2.
  • the output voltage V_o is 0 or Vbus/6.
  • the output voltage V_o is Vbus/6 or Vbus/3, when 2
  • the output voltage V_o is Vbus/3 or Vbus/2.
  • the leakage inductance Lcm of the coupled inductor 640 cooperates with the filter circuit 650 to function as an output filter, thereby eliminating the inductance in the filter circuit. Therefore, the filter circuit 650 can include only a capacitor. Since the filter circuit 650 only needs a capacitor to achieve a better filtering effect, the cost of the output filter circuit 650 is reduced, thereby facilitating suppression of output harmonics.
  • the high-frequency component of the output of the multi-level bridge arm changes by 3 times the switching frequency. In other words, V_l changes with the switching frequency, and the V_o changes frequency is V_l. Three times, this can improve the cutoff frequency of higher harmonics and reduce the cost of the filter circuit, thus facilitating the design of the subsequent stage filter circuit.
  • FIG 8 is a circuit diagram of a power conversion circuit 800 in accordance with another embodiment of the present invention.
  • Power conversion circuit 800 is an example of the embodiment of Figure 1, Figure 2 or Figure 3.
  • the power conversion circuit is a power inverter circuit, and the power inverter circuit includes a three-way capacitor clamp type three-level bridge arm as an example. Accordingly, the number of windings of the coupled inductor is also three, but The embodiment of the present invention is not limited thereto.
  • the power conversion circuit 800 may also be a two-way three-level bridge arm or include more three-level bridge arms.
  • the circuit topology of a power conversion circuit including other numbers of three-level bridge arms is similar to the circuit topology of a power conversion circuit including three-way three-level bridge arms, and will not be described herein.
  • the power conversion circuit 800 includes a DC bus (Bus) 810, a voltage dividing circuit 820, a three-way three-way bridge arm 830, a coupled inductor 840, and a filter circuit 850.
  • the first terminal of the power conversion circuit 800 is connected to the positive terminal (Bus_+) of the DC bus, and the second terminal is connected to the negative terminal (Bus_-) of the DC bus.
  • the voltage dividing circuit includes a first capacitor C1 and a second capacitor C2.
  • the first capacitor C1 is connected between Bus+ and the midpoint Bus_N of the voltage dividing circuit, and the second capacitor C2 is connected between Bus- and Bus_N.
  • the three-way three-level bridge arm 830 includes a three-level bridge arm A, a three-level bridge arm B, and a three-level bridge arm C.
  • Each of the three-level bridge arms includes a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube, and a first diode connected in parallel with the first switch tube and a second switch connected in parallel with the second switch tube a diode, a third diode connected in parallel with the third switch, and a fourth diode connected in parallel with the fourth switch.
  • the AC nodes of each of the three-level bridge arms are respectively connected to the windings of the corresponding coupled inductors.
  • the first switch tube Q1 and the second switch tube Q2 are connected in series between the Bus_+ of the DC bus and the AC node of the three-level bridge arm; the third switch tube Q3 and the fourth The switch tube Q4 is connected in series between the Bus_- of the DC bus and the AC node of the three-level bridge arm; the cathode of the first diode is connected to the Bus_+, and the cathode of the second diode is connected to the first diode Positive pole, the anode of the fourth diode is connected to Bus_ -, the anode of the third diode is connected to the negative of the fourth diode a capacitor (eg, a flying capacitor) is bridged between the anode of the first diode and the cathode of the fourth diode.
  • a capacitor eg, a flying capacitor
  • the winding of the coupled inductor 840 shares a magnetic core, the magnetic core includes three cylinders, the two ends of which are respectively magnetically connected, the three windings are respectively wound on the three cylinders and the winding directions are the same, three windings The three head ends are respectively connected to the AC nodes of the three-way three-level bridge arms, and the three tail ends of the three windings are connected to the third terminal of the power conversion circuit.
  • Filter circuit 850 can be capacitor C3.
  • the capacitor C3 is connected between the third terminal of the power conversion circuit and the midpoint of the voltage dividing circuit 820.
  • the embodiment of the present invention is not limited thereto.
  • the filter circuit 850 may also be an LC filter circuit composed of an inductor and a capacitor or Other forms of filtering circuits. Filter circuit 850 is coupled to AC load 860.
  • filter circuit 850 is coupled to an alternating current source (not shown), i.e., filter circuit 850 receives an alternating current input.
  • FIG. 9 is a schematic block diagram of a power conversion system 900 in accordance with one embodiment of the present invention.
  • the power conversion system 900 includes a first power conversion circuit and a second power conversion circuit for implementing an AC/AC conversion.
  • the first power conversion circuit may be a power conversion circuit 200 as described in Fig. 2 for converting direct current into alternating current.
  • the second power conversion circuit may be a power conversion circuit 300 as shown in Fig. 3 for converting alternating current into direct current.
  • An input terminal of the power conversion circuit 200 is connected to an output terminal of the power conversion circuit 300.
  • the DC output of the second power conversion circuit is coupled to the DC input of the first power conversion circuit to effect AC/AC conversion.
  • Embodiments of the present invention can produce more levels of output by combining interleaved multi-level bridge arms with coupled inductors. Since the multi-channel multi-level bridge arm can realize more levels of output by means of out-of-phase operation, the control logic of the power conversion circuit is compressed. Moreover, since the number of alternating current levels can be increased by the embodiment of the present invention, the content of higher harmonics in the alternating current is reduced, so that the higher harmonics can be effectively suppressed. In addition, since the higher harmonics are effectively suppressed, it is not necessary to use a larger filter circuit for filtering, thereby reducing the filtering power. The cost of the road. In addition, AC/AC conversion is achieved by connecting the DC output of the second power conversion circuit to the DC input of the first power conversion circuit.
  • FIG. 10 is a schematic block diagram of a power conversion system 1000 in accordance with another embodiment of the present invention.
  • the power conversion system 1000 includes a first power conversion circuit and a second power conversion circuit for implementing a direct current/direct current (DC/DC) conversion.
  • the first power conversion circuit may be a power conversion circuit 200 as described in Fig. 2 for converting direct current into alternating current.
  • the second power conversion circuit may be a power conversion circuit 300 as described in Fig. 3 for converting alternating current into direct current.
  • An output terminal of the power conversion circuit 200 is connected to an input terminal of the power conversion circuit 300.
  • the AC output of the first power conversion circuit is coupled to the AC input of the second power conversion circuit to effect DC/DC conversion.
  • Embodiments of the present invention can produce more levels of output by combining interleaved multi-level bridge arms with coupled inductors. Since the multi-channel multi-level bridge arm can realize more levels of output by means of out-of-phase operation, the control logic of the power conversion circuit is compressed. Moreover, since the number of alternating current levels can be increased by the embodiment of the present invention, the content of higher harmonics in the alternating current is reduced, so that the higher harmonics can be effectively suppressed. In addition, since the higher harmonics are effectively suppressed, it is not necessary to use a larger filter circuit for filtering, thereby reducing the cost of the filter circuit. In addition, the DC output is realized by the AC output of the first power conversion circuit being connected to the AC input of the second power conversion circuit.
  • FIG 11 is a schematic block diagram of a three phase power converter 1100 in accordance with one embodiment of the present invention.
  • the three-phase power converter 1100 includes: an A-phase multi-level power conversion circuit 1130, a B-phase multi-level power conversion circuit 1140, and a C-phase multi-level power conversion circuit 1150 for performing power between three-phase alternating current and direct current Transform.
  • Each phase power conversion circuit in the A-phase multi-level power conversion circuit 1130, the B-phase multi-level power conversion circuit 1140, and the C-phase multi-level power conversion circuit 1150 is the power conversion circuit 100 as described in the embodiment of FIG. 1. .
  • Embodiments of the present invention will be implemented in each phase power conversion circuit in a three-phase power converter Interleaved parallel multi-level bridge arms combined with coupled inductors produce more levels of three-phase AC output. Since the multi-channel multi-level bridge arm can realize more levels of output by means of out-of-phase operation, the control logic of the power conversion circuit is compressed. Moreover, since the number of alternating current levels can be increased by the embodiment of the present invention, the content of higher harmonics in the alternating current is reduced, so that the higher harmonics can be effectively suppressed. In addition, since the higher harmonics are effectively suppressed, it is not necessary to use a filter circuit having a large specification for filtering, thereby reducing the cost of the filter circuit.
  • the three-phase power converter 1100 further includes: a voltage dividing circuit 1120 and a three-phase filtering circuit 1160.
  • a voltage dividing circuit 1120 is connected between the first terminal and the second terminal of each phase power conversion circuit for dividing the direct current.
  • the three-phase filter circuit 1160 includes an A-phase filter capacitor Cl, a B-phase filter capacitor C2, and a C-phase filter capacitor C3 for filtering three-phase AC power, one end of each of the three capacitors and a three-phase power conversion circuit The third terminal of the one-phase power conversion circuit is connected, and the other of the three capacitors is connected together.
  • the three-phase power converter 1100 can be a three-phase power inverter that receives the connected DC voltage 1110 and outputs three-phase AC voltages V_a, V_b and V_c through the inverter.
  • the three-phase power converter 1100 can also be a three-phase power rectifier for receiving three-phase AC input voltages V_a, V_b, and V_c, respectively, and rectifying the output DC voltage.
  • FIG. 12 is a schematic block diagram of a three phase power converter 1200 in accordance with another embodiment of the present invention.
  • the three-phase power converter 1200 includes a multi-phase power conversion circuit 1230, a B-phase multi-level power conversion circuit 1240, a C-phase multi-level power conversion circuit 1250, a voltage dividing circuit 1220, and a three-phase filtering circuit 1260.
  • the other end of each of the three-phase filter capacitor C1, the B-phase filter capacitor C2 and the C-phase filter capacitor C3 in the three-phase power converter 1200 of FIG. The midpoint of the voltage circuit 1220.
  • Embodiments of the present invention will be implemented in each phase power conversion circuit in a three-phase power converter Interleaved multi-level bridge arms are combined with coupled inductors. Since the multi-channel multi-level bridge arm can realize more levels of output by means of out-of-phase operation, the control logic of the power conversion circuit is compressed. Moreover, since the number of alternating current levels can be increased by the embodiment of the present invention, the content of higher harmonics in the alternating current is reduced, so that the higher harmonics can be effectively suppressed. In addition, since the higher harmonics are effectively suppressed, it is not necessary to use a filter circuit having a large specification for filtering, thereby reducing the cost of the filter circuit.
  • the three-phase power converter 1200 can be a three-phase power inverter that receives the input DC voltage 1210 and outputs three-phase AC voltages V_a, V_b and V_c through the inverter.
  • the three-phase power converter 1200 can also be a three-phase power rectifier for receiving the input three-phase AC voltages V_a, _1) and ⁇ _(, respectively, and rectifying the output DC voltage.
  • FIG. 13 is a schematic block diagram of a three-phase power converter 1300 in accordance with yet another embodiment of the present invention.
  • the three-phase power converter 1300 is similar to the three-phase power converter 1200 of FIG. 12.
  • the three-phase power converter 1300 includes an A-phase multi-level power conversion circuit 1330, a B-phase multi-level power conversion circuit 1340, and a C-phase multi-level. Power conversion circuit 1350, voltage dividing circuit 1320, and three-phase filter circuit 1360.
  • the three-phase power converter 1300 further includes a first neutral line N for connecting to a neutral line of the power grid, wherein the first neutral line is connected to the three-phase filter capacitor C1 and the B-phase filter capacitor C2. One end of each of the capacitors in the C-phase filter capacitor C3.
  • the three-phase power converter 1300 can be a three-phase power inverter that receives the input DC voltage 1310 and outputs three-phase AC voltages V_a, V_b and V_c through the inverter.
  • Embodiments of the present invention can produce more levels of three-phase AC output by combining interleaved multi-level bridge arms with coupled inductors in each phase of the three-phase power converter. Since the multi-channel multi-level bridge arm can realize more levels of output by means of out-of-phase operation, the control logic of the power conversion circuit is compressed. Moreover, due to the implementation of the present invention For example, an increase in the number of alternating current levels can be achieved, so that the content of higher harmonics in the alternating current is reduced, so that higher harmonics can be effectively suppressed. In addition, since the higher harmonics are effectively suppressed, it is not necessary to use a filter circuit having a large specification for filtering, thereby reducing the cost of the filter circuit.
  • the three-phase power converter 1300 can also be a three-phase power rectifier for receiving input three-phase AC voltages V_a, _1) and ⁇ _(, respectively, and rectifying and outputting DC voltages respectively.
  • FIG. 14 is a schematic block diagram of a power conversion system 1400 in accordance with another embodiment of the present invention.
  • the power conversion system 1400 includes: a voltage dividing circuit 1420, an M-way power conversion circuit 1430, a coupling inductor 1440, a filter circuit 1450, and a fourth terminal 1460.
  • the coupling inductor is two-stage as an example.
  • the two-stage coupled inductor includes: a coupled inductor in each power conversion circuit 1430 and a coupled inductor shared by the M power conversion circuits 1430.
  • the coupled inductor 1440 is similar to the coupled inductor of FIG. 4 and will not be described herein.
  • Each of the power conversion circuits of the M-channel power conversion circuit 1430 is a power conversion circuit 100 of FIG. 1 for performing power conversion between the alternating current and the direct current, and details are not described herein again.
  • the voltage dividing circuit 1420 is connected between the first terminal and the second terminal of each of the power conversion circuits in the M-channel power conversion circuit 1430 for dividing the direct current.
  • the coupled inductor 1440 includes M windings coupled through a common magnetic core for forming mutually coupled inductances, one end of each of the M windings and the third of a power conversion circuit of the M-way power conversion circuit 1430, respectively.
  • the terminals are connected, and the other end of each of the M windings is connected to the fourth terminal 1460.
  • the filter circuit 1450 is connected to the fourth terminal 1460 for filtering the alternating current, and M is greater than or equal to 2.
  • the M-channel power conversion circuit can be connected together by a coupled inductor to perform interleaved parallel operation to achieve more levels of output, thereby further expanding the overall power.
  • the filter circuit 1450 includes a capacitor connected to the fourth terminal. Since the leakage inductance generated by the coupled inductor can be used for filtering, there is no need to provide an inductance in the filter circuit. The cost of the filter circuit of the three-phase power converter can be reduced.
  • the N-way multi-level bridge arms in each of the power conversion circuits 1430 are phase-shifted at an angle of 360/( during the switching period of the drive signal of the power conversion circuit.
  • N*M) degrees are used for interleaved parallel operation.
  • the interval between the phases of the drive signals of each power conversion circuit is 360/M degrees
  • the interval between the phases of the drive signals of the N multi-level bridge arms of each power conversion circuit is 360/( N*M) degrees.
  • the number of coupled inductors is smaller in the case of the same level output, so that the coupled inductor design and production are more compact. , reducing costs.
  • the steps of a method or algorithm described in connection with the embodiments disclosed herein may be implemented in hardware, a software module executed by a processor, or a combination of both.
  • the software module can be placed in random access memory (RAM), memory, read only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or technical field. Any other form of storage medium known.

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Abstract

本发明实施例提供了一种功率变换器，包括：第一端子和第二端子，与直流电相连接。第三端子，与交流电相连接；N路多电平桥臂，并联连接到第一端子和第二端子，其中N路多电平桥臂以交错并联方式工作，N路多电平桥臂中的每个多电平桥臂包括交流电节点，并且在交流电节点产生随时间变化的多个电平，多个电平大于两个电平；耦合电感，包括：通过一个公共磁芯耦合的N个绕组，其中N个绕组中的每个绕组的一端分别与N路多电平桥臂中的一路多电平桥臂的交流电节点相连接，N个绕组中每个绕组的另一端连接到第三端子。本发明的技术方案筒化了功率变换器的控制逻辑。

Description

功率变换电路和功率变换***
技术领域
本发明实施例涉及功率变换技术， 尤其是涉及一种功率变换电路和功 率变换***。 背景技术
在现有的高压逆变技术中， 基于电力电子器件直接串联的高压变频器， 对动静态的均压电路要求较高， 并且输出电压高次谐波含量高， 需设置输 出滤波器。 多电平逆变电路的提出为解决上述问题取得了突破性的进展。 多电平逆变器的一般结构是由几个电平台阶合成阶梯波以逼近正弦输出电 压。 这种逆变器由于输出电压电平数的增加， 使得输出波形的谐波含量减 小， 开关所承受的电压应力减小， 无需均压电路， 例如， 利用开关管来辅 助中点箝位的三电平逆变电路、 二极管箝位式逆变电路以及主要应用在高 压大功率电机调速、 无功补偿、 有源滤波等领域的多电平逆变器。
在三电平逆变电路基础上， 可以通过增加更多功率半导体器件或者通 过低电平拓朴串联的方式可以实现更多电平输出。 然而该方案的逆变电路 的控制逻辑复杂， 不容易实现。 发明内容
本发明实施例提供一种功率变换电路和功率变换***，能够筒化功率变 换电路的控制逻辑。
一方面， 提供了一种功率变换电路， 包括： 第一端子和第二端子， 用于 与直流电相连接； 第三端子， 用于与交流电相连接； N路多电平桥臂， 并 联连接在第一端子和第二端子之间， 用于以交错并联方式工作， 其中以交 错并联方式工作是以相位错开的方式工作， 在 N路多电平桥臂中的每个多 电平桥臂的交流电节点， 产生随时间变化的多个电平， 多个电平大于两个 电平； 耦合电感， 包括通过一个公共磁芯耦合的 N个绕组， 用于形成相互 耦合的电感， 其中 N个绕组中的每个绕组的一端分别与 N路多电平桥臂中 的一路多电平桥臂的交流电节点相连接， N 个绕组中每个绕组的另一端连 接到第三端子， N大于或等于 2。
在第一种可能的实现方式中， 公共磁芯为相互连接的 N个柱体， N个 绕组分别缠绕 N个柱体， 并且 N个绕组的缠绕方向相同。
在第二种可能的实现方式中， N个绕组的匝数相同。
在第三种可能的实现方式中，第一方面的功率变换电路还包括：驱动电 路， 用于产生驱动信号， 控制 N路多电平桥臂在功率变换电路的驱动信号 的开关周期内以相位错开 360/N度的方式进行工作。
结合第三种可能的实现方式，在第四种可能的实现方式中，驱动信号具 有位于多个预设范围内的占空比， 所述多个预设范围包括 [(n-l)/N, n/N]， 其 中 n [(n-l)/N, n/N]。
在第五种可能的实现方式中， 多电平桥臂为 M电平桥臂， N路多电平 桥臂生成（M-1 ) *N+1个电平。
在第六种可能的实现方式中，第一方面的功率变换电路还包括： 滤波电 路， 与第三端子相连接， 用于对交流电进行滤波； 分压电路， 连接在第一 端子与第二端子之间， 用于对直流电进行分压。
结合第六种可能的实现方式，在第七种可能的实现方式中， 多电平桥臂 为中点箝位型多电平桥臂， 分压电路的中点连接到 N路多电平桥臂中的每 个多电平桥臂的箝位中点。
结合第六种可能的实现方式，在第八种可能的实现方式中，滤波电路为 电容。
在第九种可能的实现方式中， 多电平桥臂为电容箝位型多电平桥臂。 结合第一方面的上述任一种可能的实现方式，在第十种可能的实现方式 中， 功率变换电路为逆变器， 用于将直流电变换为交流电， 第一端子和第 二端子为输入端子， 第三端子为输出端子。
结合第一方面的第一种至第九种可能的实现方式中的任一种，在第十一 种可能的实现方式中， 功率变换电路为整流器， 用于将交流电变换为直流 电， 第三端子为输入端子， 第一端子和第二端子为输出端子。
第二方面， 提供了一种三相功率变换器， 包括： 三相功率变换电路， 用 于在三相交流电与直流电之间进行功率变换， 其中每相功率变换电路为如 第一方面所述功率变换电路。
在第一种可能的实现方式中，第二方面的三相功率变换器还包括： 分压 电路， 连接在每相功率变换电路的第一端子与第二端子之间， 用于对直流 电进行分压； 三相滤波电路， 包括三个电容，用于对三相交流电进行滤波， 三个电容中的每个电容的一端分别与三相功率逆变电路中的一相功率逆变 电路的第三端子相连接， 三个电容的另一端连接在一起。
结合第二方面的第一种可能的实现方式， 在第二种可能的实现方式中， 三个电容的另一端共同连接到分压电路的中点。
结合第二方面的第二种可能的实现方式， 在第三种可能的实现方式中， 第二方面的三相功率变换器还包括：第一中线，用于与电网的中线相连接， 其中第一中线连接到三个电容连接在一起的一端。
第三方面， 提供了一种功率变换***， 包括： M路功率变换电路， 用 于进行在交流电与直流电之间进行功率变换， 其中， M路功率变换电路中 的每路功率变换电路为如第一方面所述的功率变换电路； 分压电路， 连接 在 M路功率变换电路中的每路功率变换电路的第一端子与第二端子之间， 用于对直流电进行分压； 第四端子； 耦合电感， 包括通过一个公共磁芯耦 合的 M个绕组， 用于形成相互耦合的电感， M个绕组中的每个绕组的一端 分别与 M路功率变换电路中的一路功率变换电路的第三端子相连接， M个 绕组中每个绕组的另一端连接到第四端子；滤波电路，与第四端子相连接， 用于对交流电进行滤波， M大于或等于 2。 在第一种可能的实现方式中， 滤波电路包括与第四端子连接的电容。 在第二种可能的实现方式中， M路功率变换电路中的每个功率变换电 路中的 N路多电平桥臂在功率变换电路的驱动信号的开关周期内以相位错 开的角度为 360/ ( N*M )度的方式进行交错并联工作。
第四方面， 提供了一种功率变换***， 包括： 第一功率变换电路为如第 一方面的第十种可能的实现方式所述的功率变换电路， 用于将直流电变换 成交流电； 第二功率变换电路为如第一方面的第十种可能的实现方式所述 的功率变换电路， 用于将交流电变换成直流电， 其中所述第一功率变换电 路的输出端子与所述第二功率变换电路的输入端子相连接， 或者所述第二 功率变换电路的输出端子与所述第一功率变换电路的输入端子相连接。
本发明的技术方案通过交错并联的多路多电平桥臂与耦合电感相结合， 可以在每个多电平桥臂的交流节点产生的多个交流电平， 并且在与耦合电 感连接的交流端子上产生更多个交流电平。 由于多路多电平桥臂可以通过 错相工作的方式实现更多个电平的输出， 因此， 筒化了功率变换电路的控 制逻辑。 附图说明
为了更清楚地说明本发明实施例的技术方案， 下面将对实施例或现有 技术描述中所需要使用的附图作筒单地介绍， 显而易见地， 下面描述中的 附图仅仅是本发明的一些实施例， 对于本领域普通技术人员来讲， 在不付 出创造性劳动性的前提下， 还可以根据这些附图获得其他的附图。
图 1是根据本发明的实施例的功率变换电路的示意性框图。
图 2是根据本发明的另一实施例的功率变换电路的示意性框图。
图 3是根据本发明的又一实施例的功率变换电路的框图。
图 4是根据本发明的一个实施例的耦合电感的等效电路图。
图 5A是根据本发明的一个实施例的多电平桥臂的电路图。 图 5B是根据本发明的一个实施例的多电平桥臂的驱动信号的示意性时 序图。
图 5C是根据本发明的另一实施例的多电平桥臂的电路图。
图 6是根据本发明的一个实施例的功率变换电路的电路图。
图 7是根据本发明的一个实施例的驱动信号的占空比和输出电压的示 意性时序图。
图 8是根据本发明的又一实施例的功率变换电路的电路图。
图 9是根据本发明的一个实施例的功率变换***的示意性框图。
图 10是根据本发明的另一实施例的功率变换***的示意性框图。
图 11是根据本发明的一个实施例的三相功率变换器的示意性框图。 图 12是根据本发明的另一实施例的三相功率变换器的示意性框图。 图 13是根据本发明的又一实施例的三相功率变换器的示意性框图。 图 14是根据本发明的另一实施例的功率变换***的示意性框图。 具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行 清楚、 完整地描述， 显然， 所描述的实施例是本发明一部分实施例， 而不 是全部的实施例。 基于本发明中的实施例， 本领域普通技术人员在没有作 出创造性劳动前提下所获得的所有其他实施例， 都属于本发明保护的范围。
交错并联技术是提高功率变换器的功率容量的一种有效方案。采用交错 并联方案， 既可方便地提高变流器的功率等级， 又可减小输入、 输出电流 纹波， 还可提高变流器的动态响应， 减小电路中磁性元件的体积和实现变 流器的自动均流。 虽然可以通过使用交错并联的两电平桥臂结合耦合电感 实现多电平输出的拓朴， 然而这种方案需要滤波电路对输出的多电平波形 进行滤波， 不利于抑制高次谐波。
图 1是根据本发明的实施例的功率变换电路 100的示意性框图。功率变 换电路 100包括： 第一端子 110、 第二端子 120、 第三端子 130、 N路多电 平桥臂 140和耦合电感 150。
第一端子 110和第二端子 120与直流电相连接。第三端子 130与交流电 相连接。 N路多电平桥臂 140包括： 多电平桥臂 1、 多电平桥臂 2 多 电平桥臂 N, 并联连接在第一端子 110和第二端子 120之间， 其中 N路多 电平桥臂 140 以交错并联方式工作， 以交错并联方式工作是指以相位错开 的方式工作， 在 N路多电平桥臂 140中的每个多电平桥臂的交流电节点， 产生随时间变化的多个电平， 多个电平大于两个电平。 耦合电感 150 包括 通过一个公共磁芯耦合的 N个绕组， 用于形成相互耦合的电感， 其中 N个 绕组中的每个绕组的一端分别与 N路多电平桥臂中的一路多电平桥臂的交 流电节点相连接， N个绕组中每个绕组的另一端连接到第三端子 130, N大 于或等于 2。
根据本发明的实施例， 功率变换电路 100可以为整流电路或逆变电路。 例如， 当第一端子和第二端子为输入端， 第三端子为输出端时， 功率变换 电路 100为逆变电路。 相反， 当第三端子为输入端， 第一端子和第二端子 为输出端时， 功率变换电路 100为整流电路。
多电平桥臂也称为多电平拓朴， 包括多个开关管， 多个开关管可以在驱 动信号的控制下互补导通或关断， 使得能够在多电平桥臂的交流节点上生 成随时间变化的多个电平， 或者在交流节点上随时间呈现多个电平。 交错 并联是指多个多电平桥臂并联工作， 并且多个多电平桥臂的驱动信号的相 位之间相隔预设的角度， 例如， 360/N度。 例如， N路多电平桥臂 140可以 以相位错开预设角度的方式工作。 举例来说， 三路三电平桥臂的驱动信号 的相位之间的相隔为 120度， 五路三电平桥臂的驱动信号的相位之间的间 隔为 72度。
根据本发明的实施例， N个绕组通过一个磁芯耦合而成耦合电感， N路 多电平桥臂连接至该耦合电感的 N个绕组， 使得 N路多电平桥臂中的每路 多电平桥臂产生的多个电平通过耦合电感合并成更多个电平。 例如， 包括 三路三电平桥臂的功率变换电路可以在与耦合电感连接的第三端子生成七 个电平。 再如， 包括三路五电平桥臂的功率变换电路可以在与耦合电感连 接的第三端子生成十三个电平。
应理解，两个相邻多电平桥臂的驱动信号的相位之间的间隔可以是相同 的角度， 例如， 360/N度， 也可以是不同的角度。 在本发明的实施例， 将该 相位间隔设置为相同的角度使得多电平桥臂的控制方法更筒单。
本发明的技术方案通过交错并联的多路多电平桥臂与耦合电感相结合， 可以在每个多电平桥臂的交流节点产生的多个交流电平， 并且在与耦合电 感连接的交流端子上产生更多个交流电平。 由于多路多电平桥臂可以通过 错相工作的方式实现更多个电平的输出， 因此， 筒化了功率变换电路的控 制逻辑。
而且， 由于本发明的实施例的可以实现交流电平数目的增加，使得交流 电中的高次谐波的含量减小， 从而可以有效抑制高次谐波。
另外， 由于高次谐波得到有效抑制， 因此， 无需使用规格较大的滤波电 路进行滤波， 从而降低了滤波电路的成本。
根据本发明的实施例，多电平桥臂为中点箝位型多电平桥臂或电容箝位 型多电平桥臂。 本发明的实施例的多电平桥臂并不限于此这两种多电平桥 臂， 例如， 也可以为混合型多电平桥臂。
根据本发明的实施例， 多电平桥臂为 M电平桥臂， N路多电平桥臂生 成（M-1 ) *N+1个电平。 例如， 多电平桥臂为三电平桥臂， N路多电平桥 臂生成 2N+1个电平。 例如， 三路三电平桥臂生成七个电平， 五路三电平桥 臂生成 13个电平。
根据本发明的实施例， N个绕组的匝数相同。 采用 N个绕组设置相同 的匝数的方案可以减小纹波电流， 从而进一步抑制高次谐波。
根据本发明的实施例， 公共磁芯为相互连接的 N个柱体， N个绕组分 别缠绕 N个柱体， 并且 N个绕组的缠绕方向相同。 换句话说， N路多电平 桥臂可以分别连接到 N个绕组的同名端。 由于这样的耦合电感的结构可以 产生漏感， 因此无需在滤波电路中设置电感，从而降低了滤波电路的成本。
根据本发明的实施例， 图 1的功率变换电路 100还包括： 驱动电路， 用 于产生驱动信号， 控制 N路多电平桥臂在功率变换电路的驱动信号的开关 周期内以相位错开 360/N度的方式进行工作。 换句话说， N路多电平桥臂 可以按照驱动波形 （或脉沖）相同的驱动信号进行工作， 只是相邻多电平 桥臂的驱动信号的相位相差 360/N度。 例如， 驱动信号可以为脉沖宽度调 制 （ Pulse Width Modulation, PWM )信号。
根据本发明的实施例，驱动信号具有位于多个预设范围内的占空比，所 述多个预设范围包括 [(n-l)/N, n/N] , 其中 n [(n-l)/N, n/N]。 第三端子的多电 平的输出状态取决于占空比的预设范围。 通过调整驱动信号的占空比， 使 得每路多电平桥臂产生的电平能够在第三端子合成更多个电平。
图 2是根据本发明的另一实施例的功率变换电路 200的示意性框图。功 率变换电路 200包括： 第一端子 210、 第二端子 220、 第三端子 230、 N路 多电平桥臂 240和耦合电感 250。功率变换电路 200与图 1的功率变换电路 100类似， 在此适当省略详细的描述。
图 2的功率变换电路还包括： 分压电路 260、 参考电压端子 270以及滤 波电路 280。 滤波电路 280的一端与第三端子 330相连接， 滤波电路 280的 另一端与参考电压端子 270相连接， 用于对交流电进行滤波。 分压电路 260 连接在第一端子 210与第二端子 220之间， 用于对直流电进行分压。 参考 电压端子 270用于接收参考电压， 例如， 与分压电路 260的中点相连接， 而分压电路的中点可以接收参考电压。 分压电路 260 的中点还连接到多电 平桥臂的箝位中点。 在相位交错的驱动信号的控制下， 多电平桥臂 1、 多电 平桥臂 2、 …、多电平桥臂 N分别在其交流节点产生多电平的交流电 V_l、 V_2 V_N。 多电平的交流电 _1、 V_2 V_N在经过耦合电感后 在第三端子合并成更多平的交流电。
根据权利要求 7的功率变换电路，其特征在于， 多电平桥臂为中点箝位 型多电平桥臂， 分压电路的中点连接到 N路多电平桥臂中的每个多电平桥 臂的箝位中点。
根据本发明的实施例，滤波电路 280为电容。本发明的实施例采用耦合 电感产生的漏感与电容 280构成滤波电路， 因此无需在滤波电路中设置电 感， 这样可以缩小滤波电路的尺寸和成本， 从而缩小了功率变换电路的尺 寸， 并且降低了功率变换电路的成本。
可选地，作为另一实施例，滤波电路还可以包括电感，例如，该电感（未 示出）可以串联连接在第三端子 230与耦合电感 250之间。
根据本发明的实施例，功率变换电路 200为逆变器，用于将直流电变换 为交流电， 第一端子和第二端子为输入端子， 接收直流输入， 第三端子为 输出端子， 输出交流电。
图 3是根据本发明的又一实施例的功率变换电路 300的示意性框图。功 率变换电路 300包括： 第一端子 310、 第二端子 320、 第三端子 330、 N路 多电平桥臂 340和耦合电感 350。功率变换电路 300与图 1的功率变换电路 100类似， 在此适当省略详细的描述。 图 3的功率变换电路还包括： 分压电 路 360、 参考电压端子 370以及滤波电路 380。 滤波电路 380的一端与第三 端子 330相连接， 滤波电路 380的另一端与参考电压端子 370相连接， 用 于对交流电进行滤波。 分压电路 360连接在第一端子 310与第二端子 320 之间， 用于对直流电进行分压。 参考电压端子 370用于接收参考电压， 例 如， 与分压电路 360的中点相连接。 分压电路 360的中点还连接到多电平 桥臂的箝位中点。 在相位交错的驱动信号的控制下， 交流电经过耦合电感
350后， 分别在多电平桥臂 1、 多电平桥臂 2 多电平桥臂 N的交流节 点产生多电平的交流电 V_l、 V_2 V_N。
与图 2的实施例不同的，功率变换电路 300为整流器，用于将交流电变 换为直流电， 第三端子 330为输入端子， 用于接收交流输入， 第一端子 310 和第二端子 320为输出端子， 用于输出直流电。
图 4是根据本发明的一个实施例的耦合电感的等效电路图。
本实施例以耦合电感包括三个绕组为例进行说明。假设三个绕组分别与 多电平桥臂 A、 多电平桥臂 B、 多电平桥臂 C的输出端相连接， 三个绕组 共用一个磁芯。 多电平桥臂 A、 多电平桥臂 B、 多电平桥臂 C在驱动信号 的开关周期内错相 360/3=120。 工作， 即以相位错开 120。 的方式交错并联 工作， 耦合电感在这种情况下可以等效为图 4所示的工作模型， 其中 Lab、 Lbc和 Lea为等效耦合电感， Lcm为漏感。根据图 4的等效耦合电感的工作 模型， 可以得到 V_o=(V_l+V_2+V_3)/3。 由于多电平桥臂八、 多电平桥臂 B、 多电平桥臂 C在驱动信号的开关周期内错相 360/3=120。 工作， 因此， 在用于逆变电路时， 耦合电感可以根据 V_l、 V_2和 V_3的不同状态合并 得到 V_o的多个不同的电平状态。 或者， 在用于整流电路时， 可以将输入 的交流电变成多电平交流电 V_l、 V_2和 V_3。
另夕卜，耦合电感的磁芯各个部分可以根据自身磁通变换量选取不同磁芯 材料进行组合。
图 5A是根据本发明的一个实施例的多电平桥臂的电路图。 图 5B是根 据本发明的一个实施例的多电平桥臂的驱动信号的示意性时序图。
参见图 5A, 本实施例以中点箝位型三电平桥臂为例如进行说明。 中点 箝位型三电平桥臂包括第一开关 Q1至第四开关 Q4以及第一二极管 D1至 第四二极管 D4。
第一开关管 Q1连接在功率变换电路的第一端子与多电平桥臂的交流电 节点之间。 第一二极管 D1与第一开关管 Q1并联， 第一二极管 D1的正极 连接到多电平桥臂的交流电节点。第三开关管 Q3的一端与多电平桥臂的交 流电节点相连接。 第三二极管 D3与第三开关管 Q3并联， 第三二极管 D3 的正极与多电平桥臂的交流电节点相连接。第二开关管 Q2的一端与分压电 路的中点相连接， 第二开关管 Q2的另一端与第三开关管 Q3的另一端相连 接。 第二二极管 D2与第二开关管 Q2并联， 第二二极管 Q2的正极与分压 电路的中点相连接。第四开关管 Q4连接在功率变换电路的第二端子与多电 平桥臂的交流电节点之间。 第四二极管 D4与第四开关管 Q4并联， 第四二 极管 D4的负极连接到多电平桥臂的交流电节点。
参见图 5B, 描述每个三电平桥臂的控制方法。 在每个开关周期的第一 半周内， 第三开关管 Q3开通， 第四开关管 Q4关断， 第一开关管 Q1在第 一脉沖的驱动下开通和关断，第二开关管 Q2在第二脉沖的驱动下开通和关 断， 第一脉沖与第二脉沖反相， 在每个开关周期的第二半周内， 第一开关 管 Q1关断， 第二开关管 Q2开通， 第三开关管 Q3在第三脉沖的驱动下开 通和关断， 第四开关管 Q4在第四脉沖的驱动下开通和关断， 第三脉沖与第 四脉沖反相。 上述四个开关管的开关状态与输出电压关系如表 1所示。
表 1 四个开关管的开关状态与输出电压关系
Ql Q2 Q3 Q4输出电压
ON OFF ON OFF Vdc/2
OFF ONONOFF 0
OFF ON OFF ON-Vdc/2
从上表中可以看出， 输出电压根据开关的不同状态呈现 Vdc/2、 0 和 -Vdc/2三个电平状态。
应理解的是， 图 5A的三电平桥臂只是中点箝位型三电平桥臂的一个例 子， 中点箝位型三电平桥臂还可以有其它变形。
图 5C是根据本发明的另一实施例的多电平桥臂的电路图。 以三电平桥 臂为例， 参见图 5C, 三电平桥臂包括： 第一开关管 Q1至第四开关管 Q4、 分别与第一开关管 Q1至第四开关管 Q4并联连接的第一二极管 D1至第四 二极管 D4。 另外， 还包括用于中点箝位的二极管 D5和 D6。
根据本发明的实施例，本发明的开关管可以但不限于金属氧化物半导体 ( Metal Oxide Semiconductor , MOSFET )、 绝缘栅双极型晶体管 (Insulated Gate Bipolar Transistor , IGBT)、 集成门极换流晶闸管（Integrated Gate Commutated Thyristors, IGCT)或可控硅整流器（ Silicon Controlled Rectifier, SCR )等功率器件或不同功率器件的组合形式。
图 6是根据本发明的一个实施例的功率变换电路 600的电路图。功率变 换电路 600是图 1、 图 2或图 3的实施例的例子。
本实施例以功率变换电路为功率逆变电路且该功率逆变电路包括三路 中点箝位型三电平桥臂为例进行说明， 相应地， 耦合电感的绕组的数目也 为三个， 但本发明的实施例并不限于此， 例如， 功率变换电路 600也可以 包括两路三电平桥臂或者包括更多路三电平桥臂。 包括其它数目的三电平 桥臂的功率变换电路的电路拓朴与包括三路三电平桥臂的功率变换电路的 电路拓朴类似， 在此不再赘述。
功率变换电路 600包括直流母线（Bus ) 610、 分压电路 620、 三路三电 平桥臂 630、 耦合电感 640和滤波电路 650。
功率变换电路 600的第一端子与直流母线的正极（ Bus_+ )相连接， 第 二端子与直流母线的负极（ Bus_- )相连接。
分压电路包括第一电容 C1和第二电容 C2, 第一电容 C1连接在 Bus+ 与分压电路的中点 Bus_N之间， 第二电容 C2连接在 Bus-与 Bus_N之间。
三路三电平桥臂 630包括三电平桥臂 A、三电平桥臂 B和三电平桥臂 C。 每路三电平桥臂的电路拓朴和驱动信号的时序图如图 5A和图 5B所示， 在 此不再赘述。 每路三电平桥臂的交流节点分别连接到相应的耦合电感的绕 组。每个三电平桥臂的第二开关管 Q2和第三开关 Q3串联连接在 Bus_N与 三电平桥臂的交流节点之间。每个三电平桥臂的第一开关管 Q1连接在直流 母线的 Bus_+与该三电平桥臂的交流节点之间。每个三电平桥臂的第四开关 管 Q4连接在直流母线的 Bus_-与该三电平桥臂的交流节点之间。 每个三电 平桥臂的箝位中点与分压电路的中点相连接。 分压电路的中点接收参考电 压。
耦合电感 640的三个绕组共用一个磁芯，该磁芯包括三个柱体，三个柱 体的两端分别被磁性连接， 三个绕组分别缠绕在三个柱体上且缠绕方向相 同， 三个绕组的三个首端分别与三路三电平桥臂的交流节点连接， 三个绕 组的三个尾端与该功率变换电路的第三端子相连接。
滤波电路 650可以为电容 C3。 电容 C3连接在功率变换电路的第三端 子与分压电路的中点之间， 根据本发明的实施例并不限于此， 例如， 滤波 电路 650也可以为由电感和电容组成的 LC滤波电路或者其它形式的滤波电 路。 滤波电路 650与交流负载 660相连接。
应理解的是， 当功率变换电路 600为整流器时，滤波电路 650与交流电 源 （未示出 )相连接， 即滤波电路 650接收交流电输入。
图 7 是根据本发明的一个实施例的驱动信号的占空比和输出电压的示 意性时序图。
根据本发明的实施例，可以通过为功率变换电路的驱动信号设置合适的 占空比， 使得多路多电平桥臂随着时间的变化在交流电节点产生多个电平， 并且多个电平在耦合电感处进行合并， 得到更多的电平状态。 功率变换电 路的驱动信号可以在不同的工频周期内设置有不同的占空比 D。 例如， 在 采用三路三电平桥臂情况下， 占空比可以设置为 E 1/3, l/3 < D < 2/3, 2/3 < D < 1 , 这样可以得到七个电平状态。
从图 4的实施例可知， V_o=(V_l+V_2+V_3)/3 , 根据 V_l、 V_2和 V_3 随时间变化的不同电平状态， 可以在驱动信号的工频周期的正半周和负半 周内得到功率变换电路的不同输出电压 V_o, 如表 2所示。
表 2 不同占空比状态下 V_o随不同三电平桥臂的输出电压的变化 占空比 ^犬态 V_l V_2 V_3 V_o
2/3 < D < 1 Vbus/2 Vbus/2 Vbus/2 Vbus/2
1/3 < D < 2/3 Vbus/2 Vbus/20 Vbus/3 0 < D < 2/3 Vbus/20 0 Vbus/6
0 < D < 1/3 0 0 0 0
0 < D < 2/3 -Vbus/2 0 0 -Vbus/6
1/3 < D < 2/3 -Vbus/2 -Vbus/2 0 -Vbus/3
2/3 < D < 1 -Vbus/2 -Vbus/2 -Vbus/2 -Vbus/2
功率变换器的输出电压 V_o根据整个工频周期内占空比所处的不同状 态而变化， 如表 2所示， 在正半周， 如果占空比的状态 （或者变化范围） 为 2/3 D l , 则 _0为 Vbus/2, 而在负半周， 如果占空比的状态为 2/3 D < 1 , 则 V_o为 -Vbus/2。
参见图 7 ,下面以工频周期的正半周为例进行说明，随占空比 D的不同， 其 V_l , V_2, V_3的组合状态分别如下：
当占空比 D<=l/3时， 输出电压 V_o为 0或 Vbus/6, 当 l/3<=D<=2/3 时，输出电压 V_o为 Vbus/6或者 Vbus/3 , 当 2/3<=D<=l时，输出电压 V_o 为 Vbus/3或 Vbus/2。
由此，在工频周期的正半周内， 随着占空比 D变化，产生了 4个电平：
0、 Vbus/6, Vbus/3和 Vbus/2,在工频周期的负半周内，同理可得 4个电平： 0、 -Vbus/6, -Vbus/3和 -Vbus/2, 因此，在工频周期内共产生 7个电平状态。 根据本发明的实施例， 如果在整个工频周期内， 占空比在 0-2/3变化， 则能 够产生 5 电平的效果。 由此可见， 第三端子的多电平的输出状态取决于占 空比的状态或变化范围。
另外， 耦合电感 640的漏感 Lcm与滤波电路 650配合， 可以起到输出 滤波的作用， 这样可以省去滤波电路中的电感。 因此， 滤波电路 650可以 只包括电容。 由于滤波电路 650只需要电容即可实现比较好的滤波效果， 因此， 降低了输出滤波电路 650 的成本， 从而有利于对输出谐波的抑制。 同时由于三路多电平桥臂交错工作，多电平桥臂的输出量中的高频分量以 3 倍开关频率变化，换句话说， V_l以开关频率变化，而 V_o变化频率为 V_l 的三倍， 这样能够提高高次谐波的截止频率， 降低滤波电路的成本， 从而 有利于后级滤波电路的设计。
图 8是根据本发明的另一实施例的功率变换电路 800的电路图。功率变 换电路 800是图 1、 图 2或图 3的实施例的例子。
本实施例以功率变换电路为功率逆变电路且该功率逆变电路包括三路 电容箝位型三电平桥臂为例进行说明， 相应地， 耦合电感的绕组的数目也 为三个， 但本发明的实施例并不限于此， 例如， 功率变换电路 800也可以 两路三电平桥臂或者包括更多路三电平桥臂。 包括其它数目的三电平桥臂 的功率变换电路的电路拓朴与包括三路三电平桥臂的功率变换电路的电路 拓朴类似， 在此不再赘述。
功率变换电路 800包括直流母线（Bus ) 810、 分压电路 820、 三路三电 平桥臂 830、 耦合电感 840、 滤波电路 850。
功率变换电路 800的第一端子与直流母线的正极（ Bus_+ )相连接， 第 二端子与直流母线的负极（ Bus_- )相连接。
分压电路包括第一电容 C1和第二电容 C2, 第一电容 C1连接在 Bus+ 与分压电路的中点 Bus_N之间， 第二电容 C2连接在 Bus-与 Bus_N之间。
三路三电平桥臂 830包括三电平桥臂 A、三电平桥臂 B和三电平桥臂 C。 每路三电平桥臂包括第一开关管、第二开关管、第三开关管和第四开关管， 以及与第一开关管并联的第一二极管、 与第二开关管并联的第二二极管、 与第三开关管并联的第三二极管以及与第四开关管并联的第四二极管。 每 路三电平桥臂的交流节点分别连接到相应的耦合电感的绕组。
在每个三电平桥臂中， 第一开关管 Q1和第二开关管 Q2串联连接在直 流母线的 Bus_+与该三电平桥臂的交流节点之间； 第三开关管 Q3和第四开 关管 Q4串联连接在直流母线的 Bus_-与该三电平桥臂的交流节点之间； 第 一二极管的负极连接到 Bus_+, 第二二极管的负极连接到第一二极的正极， 第四二极管的正极连接到 Bus_ -,第三二极管的正极连接到第四二极管的负 极；在第一二极管的正极与第四二极管的负极之间跨接用于箝位的电容（例 如， 飞跨电容）。
耦合电感 840的绕组共用一个磁芯，该磁芯包括三个柱体，三个柱体的 两端分别被磁性连接， 三个绕组分别缠绕在三个柱体上且缠绕方向相同， 三个绕组的三个首端分别与三路三电平桥臂的交流节点连接， 三个绕组的 三个尾端与该功率变换电路的第三端子相连接。
滤波电路 850可以为电容 C3。 电容 C3连接在功率变换电路的第三端 子与分压电路 820 的中点之间， 本发明的实施例并不限于此， 例如， 滤波 电路 850也可以为由电感和电容组成的 LC滤波电路或者其它形式的滤波电 路。 滤波电路 850与交流负载 860相连接。
应理解的是， 当功率变换电路 800为整流器时，滤波电路 850与交流电 源 （未示出 )相连接， 即滤波电路 850接收交流电输入。
图 9是根据本发明的一个实施例的功率变换*** 900的示意性框图。功 率变换*** 900 包括第一功率变换电路和第二功率变换电路， 用于实现交 流 /交流（AC/AC ) 变换。 第一功率变换电路可以为如图 2所述的功率变换 电路 200, 用于将直流电变换成交流电。 第二功率变换电路可以为如图 3所 述的功率变换电路 300, 用于将交流电变换成直流电。 功率变换电路 200的 输入端子与功率变换电路 300 的输出端子相连接。 换句话说， 第二功率变 换电路的直流输出连接到第一功率变换电路直流输入， 从而实现 AC/AC变 换。
本发明的实施例通过交错并联的多电平桥臂与耦合电感相结合，可以产 生更多电平的输出。 由于多路多电平桥臂可以通过错相工作的方式实现更 多个电平的输出， 因此， 筒化了功率变换电路的控制逻辑。 而且， 由于本 发明的实施例的可以实现交流电平数目的增加， 使得交流电中的高次谐波 的含量减小， 从而可以有效抑制高次谐波。 另外， 由于高次谐波得到有效 抑制， 因此， 无需使用规格较大的滤波电路进行滤波， 从而降低了滤波电 路的成本。 另外， 通过将第二功率变换电路的直流输出连接到第一功率变 换电路直流输入， 从而实现 AC/AC变换。
图 10是根据本发明的另一实施例的功率变换*** 1000的示意性框图。 功率变换*** 1000包括第一功率变换电路和第二功率变换电路， 用于实现 直流 /直流（DC/DC ) 变换。 第一功率变换电路可以为如图 2所述的功率变 换电路 200, 用于将直流电变换成交流电。 第二功率变换电路可以为如图 3 所述的功率变换电路 300, 用于将交流电变换成直流电。 功率变换电路 200 的输出端子与功率变换电路 300 的输入端子相连接。 换句话说， 第一功率 变换电路的交流输出连接到第二功率变换电路交流输入， 从而实现 DC/DC 变换。
本发明的实施例通过交错并联的多电平桥臂与耦合电感相结合，可以产 生更多电平的输出。 由于多路多电平桥臂可以通过错相工作的方式实现更 多个电平的输出， 因此， 筒化了功率变换电路的控制逻辑。 而且， 由于本 发明的实施例的可以实现交流电平数目的增加， 使得交流电中的高次谐波 的含量减小， 从而可以有效抑制高次谐波。 另外， 由于高次谐波得到有效 抑制， 因此， 无需使用规格较大的滤波电路进行滤波， 从而降低了滤波电 路的成本。 另外， 通过第一功率变换电路的交流输出连接到第二功率变换 电路交流输入， 从而实现 DC/DC变换。
图 11是根据本发明的一个实施例的三相功率变换器 1100的示意性框图。 三相功率变换器 1100包括： A相多电平功率变换电路 1130、 B相多电平功 率变换电路 1140、 C相多电平功率变换电路 1150, 用于在三相交流电与直 流电之间进行功率变换。
A相多电平功率变换电路 1130、 B相多电平功率变换电路 1140、 C相 多电平功率变换电路 1150中的每相功率变换电路为如图 1的实施例所述的 功率变换电路 100。
本发明的实施例通过在三相功率变换器中的每一相功率变换电路中将 交错并联的多电平桥臂与耦合电感相结合， 可以产生更多电平的三相交流 电输出。 由于多路多电平桥臂可以通过错相工作的方式实现更多个电平的 输出， 因此， 筒化了功率变换电路的控制逻辑。 而且， 由于本发明的实施 例的可以实现交流电平数目的增加， 使得交流电中的高次谐波的含量减小， 从而可以有效抑制高次谐波。 另外， 由于高次谐波得到有效抑制， 因此， 无需使用规格较大的滤波电路进行滤波， 从而降低了滤波电路的成本。
可选地，作为另一实施例，三相功率变换器 1100还包括：分压电路 1120 和三相滤波电路 1160。分压电路 1120连接在每相功率变换电路的第一端子 与第二端子之间， 用于对直流电进行分压。 三相滤波电路 1160包括 A相滤 波电容 Cl、 B相滤波电容 C2和 C相滤波电容 C3, 用于对三相交流电进行 滤波， 三个电容中的每个电容的一端分别与三相功率变换电路中的一相功 率变换电路的第三端子相连接， 这三个电容中的另一端连接在一起。 三相 功率变换器 1100可以为三相功率逆变器， 分别接收接入的直流电压 1110, 并经过逆变输出三相交流电压 V_a、 V_b和 V_c。
应理解， 三相功率变换器 1100也可以为三相功率整流器， 分别用于接 收三相交流输入电压 V_a、 V_b和 V_c , 并经过整流输出直流电压。
图 12是根据本发明的另一实施例的三相功率变换器 1200的示意性框图。 三相功率变换器 1200包括 Α相多电平功率变换电路 1230、B相多电平功率 变换电路 1240、 C相多电平功率变换电路 1250、 分压电路 1220和三相滤 波电路 1260。 与图 11的三相功率变换器 1100A的 A相多电平功率变换电 路 1130、 B相多电平功率变换电路 1140、 C相多电平功率变换电路 1150、 分压电路 1120和三相滤波电路 1160类似， 在此不再赘述。 与图 11的实施 例不同的是， 图 12的三相功率变换器 1200中的三相滤波电容 Cl、 B相滤 波电容 C2和 C相滤波电容 C3中的每个电容的另一端共同连接到分压电路 1220的中点。
本发明的实施例通过在三相功率变换器中的每一相功率变换电路中将 交错并联的多电平桥臂与耦合电感相结合。 由于多路多电平桥臂可以通过 错相工作的方式实现更多个电平的输出， 因此， 筒化了功率变换电路的控 制逻辑。 而且， 由于本发明的实施例的可以实现交流电平数目的增加， 使 得交流电中的高次谐波的含量减小， 从而可以有效抑制高次谐波。 另外， 由于高次谐波得到有效抑制， 因此， 无需使用规格较大的滤波电路进行滤 波， 从而降低了滤波电路的成本。
三相功率变换器 1200可以为三相功率逆变器， 分别接收输入的直流电 压 1210, 并经过逆变输出三相交流电压 V_a、 V_b和 V_c。
应理解， 三相功率变换器 1200也可以为三相功率整流器， 分别用于接 收输入的三相交流电压 V_a、 _1)和¥_( , 并经过整流输出直流电压。
图 13是根据本发明的又一实施例的三相功率变换器 1300的示意性框图。 三相功率变换器 1300与图 12的三相功率变换器 1200类似， 三相功率变换 器 1300包括 A相多电平功率变换电路 1330、B相多电平功率变换电路 1340、 C相多电平功率变换电路 1350、 分压电路 1320和三相滤波电路 1360。 与 图 12的三相功率变换器 1200的 A相多电平功率变换电路 1230、 B相多电 平功率变换电路 1240、 C相多电平功率变换电路 1250、 分压电路 1220和 三相滤波电路 1260类似， 在此不再赘述。 与图 12的实施例不同的是， 三 相功率变换器 1300还包括第一中线 N, 用于与电网的中线相连接， 其中该 第一中线连接到三相滤波电容 Cl、 B相滤波电容 C2和 C相滤波电容 C3 中的每个电容的连接在一起的一端。 三相功率变换器 1300可以为三相功率 逆变器，分别接收输入的直流电压 1310,并经过逆变输出三相交流电压 V_a、 V_b和 V_c。
本发明的实施例通过在三相功率变换器中的每一相功率变换电路中将 交错并联的多电平桥臂与耦合电感相结合， 可以产生更多电平的三相交流 电输出。 由于多路多电平桥臂可以通过错相工作的方式实现更多个电平的 输出， 因此， 筒化了功率变换电路的控制逻辑。 而且， 由于本发明的实施 例的可以实现交流电平数目的增加， 使得交流电中的高次谐波的含量减小， 从而可以有效抑制高次谐波。 另外， 由于高次谐波得到有效抑制， 因此， 无需使用规格较大的滤波电路进行滤波， 从而降低了滤波电路的成本。
应理解， 三相功率变换器 1300也可以为三相功率整流器， 分别用于接 收输入的三相交流电压 V_a、 _1)和¥_( , 并经过整流分别输出直流电压。
图 14是根据本发明的另一实施例的功率变换*** 1400的示意性框图。 功率变换*** 1400包括： 分压电路 1420、 M路功率变换电路 1430、 耦合 电感 1440、 滤波电路 1450和第四端子 1460。
本实施例以耦合电感为两级为例进行了说明，所属领域技术人员能够理 解的是， 也可以耦合电感也可以为多级。 两级耦合电感包括： 每个功率变 换电路 1430 中的耦合电感以及 M个功率变换电路 1430共用的耦合电感
1440。
耦合电感 1440与图 4的耦合电感类似， 在此不再赘述。
M路功率变换电路 1430中的每路功率变换电路为如图 1的功率变换电 路 100, 用于进行在交流电与直流电之间进行功率变换， 在此不再赘述。 分 压电路 1420连接在 M路功率变换电路 1430中的每路功率变换电路的第一 端子与第二端子之间， 用于对直流电进行分压。 耦合电感 1440包括通过一 个公共磁芯耦合的 M个绕组， 用于形成相互耦合的电感， M个绕组中的每 个绕组的一端分别与 M路功率变换电路 1430中的一路功率变换电路的第三 端子相连接， M个绕组中每个绕组的另一端连接到第四端子 1460。 滤波电 路 1450与第四端子 1460相连接， 用于对交流电进行滤波， M大于等于 2。
根据本发明的实施例， 可以将 M路功率变换电路通过耦合电感连接在 一起进行交错并联工作， 以实现更多电平的输出， 从而进一步扩展了整机 功率。
根据本发明的实施例， 滤波电路 1450包括与第四端子连接的电容。 由 于耦合电感产生的漏感可以用于滤波， 因此无需在滤波电路中设置电感， 能够降低三相功率变换器的滤波电路的成本。
根据本发明的实施例， M路功率变换电路 1430中的每个功率变换电路 中的 N路多电平桥臂在该功率变换电路的驱动信号的开关周期内以相位错 开的角度为 360/ ( N*M )度的方式进行交错并联工作。 换句话说， 每路功 率变换电路的驱动信号的相位之间的间隔为 360/M度， 每路功率变换电路 的 N个多电平桥臂的驱动信号的相位之间的间隔为 360/ ( N*M )度。
根据本发明的实施例， 与两电平结合耦合电感产生多电平的方案相比， 在电平输出相同的情况下， 使得耦合电感的路数更少， 使得耦合电感设计 及生产更加筒单， 降低了成本。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各 示例的单元及算法步骤， 能够以电子硬件、 计算机软件或者二者的结合来 实现， 为了清楚地说明硬件和软件的可互换性， 在上述说明中已经按照功 能一般性地描述了各示例的组成及步骤。 这些功能究竟以硬件还是软件方 式来执行， 取决于技术方案的特定应用和设计约束条件。 专业技术人员可 以对每个特定的应用来使用不同方法来实现所描述的功能， 但是这种实现 不应认为超出本发明的范围。
结合本文中所公开的实施例描述的方法或算法的步骤可以用硬件、处理 器执行的软件模块， 或者二者的结合来实施。 软件模块可以置于随机存储 器（RAM )、 内存、 只读存储器（ROM )、 电可编程 ROM、 电可擦除可编 程 ROM、 寄存器、 硬盘、 可移动磁盘、 CD-ROM, 或技术领域内所公知的 任意其它形式的存储介质中。
尽管已示出和描述了本发明的一些实施例， 但本领域技术人员应理解， 在不脱离本发明的原理和精神的情况下， 可对这些实施例进行各种修改， 这样的修改应落入本发明的范围内。

Claims

权利要求
1、 一种功率变换电路， 其特征在于， 包括：
第一端子和第二端子， 用于与直流电相连接；
第三端子， 用于与交流电相连接；
N路多电平桥臂， 并联连接在所述第一端子和所述第二端子之间，用于 以交错并联方式工作， 其中所述以交错并联方式工作是以相位错开的方式 工作， 在所述 N路多电平桥臂中的每个多电平桥臂的交流电节点， 产生随 时间变化的多个电平， 所述多个电平大于两个电平；
耦合电感， 包括通过一个公共磁芯耦合的 N个绕组， 用于形成相互耦 合的电感， 其中所述 N个绕组中的每个绕组的一端分别与所述 N路多电平 桥臂中的一路多电平桥臂的交流电节点相连接， 所述 N个绕组中每个绕组 的另一端连接到所述第三端子， N大于或等于 2。
2、 根据权利要求 1所述的功率变换电路， 其特征在于， 所述公共磁芯 为相互连接的 N个柱体， 所述 N个绕组分别缠绕所述 N个柱体， 并且所述 N个绕组的缠绕方向相同。
3、 根据权利要求 1所述的功率变换电路， 其特征在于， 所述 N个绕组 的匝数相同。
4、 根据权利要求 1所述的功率变换电路， 其特征在于， 还包括： 驱动 电路， 用于产生驱动信号， 控制所述 N路多电平桥臂在所述功率变换电路 的驱动信号的开关周期内以相位错开 360/N度的方式进行工作。
5、 根据权利要求 4所述的功率变换电路， 其特征在于， 所述驱动信号 具有位于多个预设范围内的占空比， 所述多个预设范围包括 [(n-l)/N, n/N] , 其中 n [(n-l)/N, n/N] o
6、 根据权利要求 1所述的功率变换电路， 其特征在于， 所述多电平桥 臂为 M电平桥臂， 所述 N路多电平桥臂生成（M-1 ) *N+1个电平。
7、 根据权利要求 1所述的功率变换电路， 其特征在于， 还包括： 滤波电路， 与所述第三端子相连接， 用于对所述交流电进行滤波； 分压电路，连接在所述第一端子与所述第二端子之间，用于对所述直流 电进行分压。
8、 根据权利要求 7所述的功率变换电路， 其特征在于， 所述多电平桥 臂为中点箝位型多电平桥臂， 所述分压电路的中点连接到所述 N路多电平 桥臂中的每个多电平桥臂的箝位中点。
9、 根据权利要求 7所述的功率变换电路， 其特征在于， 所述滤波电路 为电容。
10、根据权利要求 1所述的功率变换电路， 其特征在于， 所述多电平桥 臂为电容箝位型多电平桥臂。
11、 一种三相功率变换器， 其特征在于， 包括：
三相功率变换电路，用于在三相交流电与直流电之间进行功率变换，其 中每相功率变换电路为如权利要求 1至 6中的任一项所述的功率变换电路。
12、 根据权利要求 11所述的三相变换器， 其特征在于， 还包括： 分压电路，连接在所述每相功率变换电路的第一端子与所述第二端子之 间， 用于对所述直流电进行分压；
三相滤波电路， 包括三个电容， 用于对所述三相交流电进行滤波， 所述 三个电容中的每个电容的一端分别与所述三相功率逆变电路中的一相功率 逆变电路的第三端子相连接， 所述三个电容的另一端连接在一起。
13、 根据权利要求 12所述的三相变换器， 其特征在于， 所述三个电容 的另一端共同连接到所述分压电路的中点。
14、 根据权利要求 13所述的三相变换器， 其特征在于， 还包括： 第一中线，用于与电网的中线相连接，其中所述第一中线连接到所述三 个电容的连接在一起的一端。
15、 一种功率变换***， 其特征在于， 包括：
M路功率变换电路， 用于进行在交流电与直流电之间进行功率变换， 其中， 所述 M路功率变换电路中的每路功率变换电路为如权利要求 1至 6 中的任一项所述的功率变换电路；
分压电路， 连接在所述 M路功率变换电路中的每路功率变换电路的第 一端子与第二端子之间， 用于对所述直流电进行分压；
第四端子；
耦合电感， 包括通过一个公共磁芯耦合的 M个绕组， 用于形成相互耦 合的电感，所述 M个绕组中的每个绕组的一端分别与所述 M路功率变换电 路中的一路功率变换电路的第三端子相连接， 所述 M个绕组中每个绕组的 另一端连接到所述第四端子；
滤波电路， 与所述第四端子相连接， 用于对所述交流电进行滤波， M 大于或等于 2。
16、 根据权利要求 15所述的功率变换***， 所述滤波电路包括与所述 第四端子连接的电容。
17、根据权利要求 15或 16所述的功率变换***，其特征在于，所述 M 路功率变换电路中的每个功率变换电路中的 N路多电平桥臂在所述功率变 换电路的驱动信号的开关周期内以相位错开的角度为 360/ ( N*M )度的方 式进行交错并联工作。
18、 一种功率变换***， 其特征在于， 包括：
第一功率变换电路为如权利要求 1至 10所述的功率变换电路， 用于将 直流电变换成交流电， 其中所述第一端子和所述第二端子为输入端子， 所 述第三端子为输出端子；
第二功率变换电路为如权利要求 1至 10所述的功率变换电路， 用于将 交流电变换成直流电， 其中所述第三端子为输入端子， 所述第一端子和所 述第二端子为输出端子， 并且所述第一功率变换电路的输出端子与所述第 二功率变换电路的输入端子相连接， 或者所述第二功率变换电路的输出端 子与所述第一功率变换电路的输入端子相连接。
PCT/CN2014/072557 2013-08-30 2014-02-26 功率变换电路和功率变换*** WO2015027693A1 (zh)

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