WO2021047154A1 - 一种升压电路及其装置和系统 - Google Patents

一种升压电路及其装置和系统 Download PDF

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Publication number
WO2021047154A1
WO2021047154A1 PCT/CN2020/077969 CN2020077969W WO2021047154A1 WO 2021047154 A1 WO2021047154 A1 WO 2021047154A1 CN 2020077969 W CN2020077969 W CN 2020077969W WO 2021047154 A1 WO2021047154 A1 WO 2021047154A1
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Prior art keywords
capacitor
diode
branch
circuit
output
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PCT/CN2020/077969
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English (en)
French (fr)
Inventor
陈书生
曾春保
林镇煌
何宏伟
林加富
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科华恒盛股份有限公司
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Publication of WO2021047154A1 publication Critical patent/WO2021047154A1/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
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/10—Parallel operation of dc sources
    • H02J1/12—Parallel operation of dc generators with converters, e.g. with mercury-arc rectifier
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

  • This application relates to the technical field of circuit boosting, and more specifically, to a boosting circuit and its device and system.
  • the input voltage of the photovoltaic power generation system is gradually increasing, and has been increased to 1500V.
  • the front-stage boost circuit of the photovoltaic inverter is usually changed from a two-level to a three-level circuit.
  • the flying capacitor type three-level boost circuit shown in Figure 1 is initially powered on, since the voltage on the flying capacitor is zero, it will cause the lower arm switch Q2 to withstand all input voltages, which may easily lead to Damage to Q2.
  • the Chinese patent document with the publication number CN108923632A proposes a multi-level Boost device, which can realize the N first switches in parallel by setting N voltage divider modules connected in series in one-to-one correspondence.
  • the voltage distribution between one switch so that the voltages at both ends of the N first switches are within a safe range. Even if the input voltage is high and the voltage on the flying capacitor is zero when the machine is turned on, the second to Nth switches can be avoided.
  • the above-mentioned documents solve to a certain extent the problem of the breakdown of the lower arm switch tube when the flying capacitor three-level boost circuit is initially powered on.
  • it still has the following shortcomings: when the boost circuit is in a normal working state, because the flying capacitor C1 participates in the boost process, its voltage value fluctuates greatly, so there are flying capacitor C1 and voltage divider capacitor C21.
  • the phenomenon of voltage imbalance If the above-mentioned imbalance is not dealt with, after several working cycles, the voltage value of the voltage dividing capacitor C21 will be higher and higher, and the voltage value of the flying capacitor C1 will be lower and lower, showing obvious polarization.
  • the voltage value of the voltage divider capacitor C21 is higher than the withstand voltage value of the corresponding lower arm switch tube, it will directly cause the breakdown of the lower arm switch, thereby damaging the circuit and causing work loss.
  • the purpose of this application is to solve the above technical problems and provide a booster circuit and its device and system.
  • the first aspect of the present application provides a booster circuit, which includes a first input terminal, a second input terminal, a first output terminal, a second output terminal, an inductor, a first controllable switch, and a second output terminal.
  • the first controllable switch and the second controllable switch form a first branch after being connected in series, wherein the first end of the first controllable switch and the second end of the second controllable switch respectively form the first branch.
  • the first diode and the second diode are connected in series to form a second branch, wherein the anode of the first diode and the cathode of the second diode respectively form the first branch of the second branch. End and second end;
  • the first capacitor, the third diode, and the second capacitor are connected in series to form a third branch, wherein the anode and the cathode of the third diode are respectively connected to one end of the first capacitor and the second capacitor, so The other ends of the first capacitor and the second capacitor respectively constitute the first end and the second end of the third branch;
  • the fourth diode constitutes a fourth branch, wherein the anode and cathode of the fourth diode constitute the first end and the second end of the fourth branch, respectively;
  • the first input terminal is connected to the first end of the first branch and the first end of the second branch through the inductor; the first end of the third branch is connected to the first diode in the second branch and the second end of the second branch.
  • the common point between the pole tubes; the first output end is connected to the second end of the second branch; the second input end is connected to the first branch, the third branch and the second output end;
  • the common point between the first controllable switch and the second controllable switch in the first branch is connected to the common point between the first capacitor and the third diode in the second branch;
  • the first end of the fourth branch is connected to the common point between the third diode and the second capacitor in the third branch, and the second end is connected to the first diode and the second capacitor in the second branch.
  • the common point between the second diodes is connected to the common point between the third diode and the second capacitor in the third branch.
  • the capacitance of the first capacitor and the second capacitor are the same.
  • a first output capacitor and a second output capacitor are connected in series between the first output terminal and the second output, and the first output capacitor and the second output capacitor have the same capacitance value.
  • the anode of the fifth diode is connected to the common point between the first output capacitor and the second output capacitor, and the cathode of the fifth diode is connected to the first diode The common point between the tube and the second diode.
  • a second aspect of the present application provides an inverter device, which includes a back-stage inverter circuit and a front-stage circuit; the front-stage circuit adopts the boost circuit as described in the foregoing technical solution;
  • the boost circuit is used to boost the voltage input from its input terminal and then output it from the output terminal; the input terminal of the inverter circuit is coupled to the output terminal of the boost circuit for inverting the direct current output from it. Change to alternating current.
  • the third aspect of the present application provides a photovoltaic power generation device, which includes a photovoltaic module, a pre-stage circuit and a post-stage circuit; the pre-stage circuit adopts the boost circuit as described in the above technical solution;
  • the photovoltaic module is coupled to the input terminal of the boost circuit; the boost circuit is used to boost the output voltage of the photovoltaic module and output it to the subsequent circuit from the output terminal.
  • the fourth aspect of the present application provides a photovoltaic power generation system, which includes a plurality of photovoltaic modules, a pre-stage circuit and a post-stage circuit; the pre-stage circuit adopts the boost circuit as described in the above technical solution ;
  • the photovoltaic module is coupled to the input terminal of the boost circuit; the boost circuit is used to boost the output voltage of the photovoltaic module and output it to the subsequent circuit from the output terminal.
  • the photovoltaic module and the booster circuit have a one-to-one correspondence.
  • the output ends of the multiple boost circuits are connected in parallel to the subsequent circuit.
  • the latter circuit is an inverter circuit, and its input terminal is coupled to the output terminal of the booster circuit for inverting the direct current outputted by it into alternating current.
  • the first capacitor is connected to the second output terminal through the third diode and the second capacitor; when power is on, the second capacitor cooperates with the first capacitor and is charged to the input respectively.
  • the voltage is half of the voltage, and the two controllable switches can be regarded as being connected in parallel with the first capacitor and the second capacitor respectively. Therefore, their voltage is limited by the voltage at both ends of the corresponding capacitor and is within a safe range. This solves the problem of flying capacitors when powering on.
  • Zero voltage leads to the problem of breakdown failure of the lower arm switch tube due to overvoltage; when selecting the first controllable switch and the second controllable switch, basically only need to use a withstand voltage slightly higher than half of the output voltage The device meets the cost requirements of device selection;
  • the boost circuit of the embodiment of the present application is provided with a fourth branch, which can establish a discharge loop for the second capacitor when the circuit is powered off, thereby improving the safety and stability of circuit operation;
  • the fourth diode on the fourth branch has its cathode connected to the common point of the first diode and the second diode.
  • the working period such as When the voltage imbalance between the first capacitor and the second capacitor occurs, the second capacitor can be discharged to the first capacitor through the fourth diode to balance the voltage between the two;
  • the boost circuit of the embodiment of the application is provided with a fifth diode, the anode of which is connected to the common point between the first output capacitor and the second output capacitor, and the cathode of which is connected to the first diode and The common point between the second diode; when there is no electricity at the input end and the output end is electrified, the bus will charge the first capacitor and the second capacitor to half the bus voltage through the fifth diode, thereby reducing the second and second The voltage across the pole tube is clamped at half the bus voltage, and the voltages borne by the first diode and the second diode are basically evenly distributed, so as to protect the second diode from breakdown;
  • the fourth diode is connected to the common point of the first diode and the second diode, that is, connected to the cathode of the fifth diode, and the fourth diode is connected to the cathode of the fifth diode.
  • the anodes of the five diodes are connected to the common point between the first output capacitor and the second output capacitor, so that the maximum potential of the cathode terminal of the fourth diode is half the bus voltage, so that it is at a safe voltage in any state Within the range, prevent it from being broken down.
  • Figure 1 is a structure diagram of a conventional flying capacitor type three-level boost circuit
  • FIG. 2 is a structural diagram of the boost circuit in Embodiment 1 of the present application.
  • FIG. 3 is a schematic diagram of the current loop of the boost circuit of the embodiment 1 of the present application when it is powered on;
  • FIG. 4 is a schematic diagram of the current loop of the boost circuit of the embodiment 1 of the present application when it is powered off;
  • FIG. 5 is a schematic diagram of the current loop when the boost circuit of Embodiment 1 of the present application is in a normal working state, and the first controllable switch is turned off and the second controllable switch is turned on;
  • FIG. 6 is a schematic diagram of the current loop when the boost circuit of Embodiment 1 of the present application is in a normal working state, and the first controllable switch is turned off and the second controllable switch is turned off;
  • FIG. 7 is a schematic diagram of the current loop when the boost circuit of Embodiment 1 of the present application is in a normal working state, and the first controllable switch is turned on and the second controllable switch is turned off;
  • FIG. 8 is a schematic diagram of the current loop when the boost circuit of Embodiment 1 of the present application is in a normal working state, and the first controllable switch is turned on and the second controllable switch is turned on;
  • FIG. 9 is a structural diagram of a boost circuit in Embodiment 2 of the present application.
  • FIG. 10 is a schematic diagram of the current loop of the boost circuit of Embodiment 2 of the present application when there is no power at the input end and there is power at the output end;
  • FIG. 11 is a schematic structural diagram of an inverter device in Embodiment 3 of the present application.
  • FIG. 12 is a schematic structural diagram of a photovoltaic power generation device according to Embodiment 4 of the present application.
  • FIG. 13 is a schematic structural diagram of a photovoltaic power generation system according to Embodiment 5 of the present application.
  • FIG. 14 is a schematic structural diagram of a photovoltaic power generation system according to Embodiment 6 of the present application.
  • Embodiment 1 of the present application provides a booster circuit having an input terminal and an output terminal.
  • the input terminal includes a first input terminal and a second input terminal
  • the output terminal includes a first output terminal and a second output terminal.
  • the boost circuit of this embodiment can be used in various application scenarios, so its input terminal can be coupled with various power input devices to receive power input therefrom.
  • the application scenarios in the field of photovoltaic power generation are taken as examples. Therefore, the input end is coupled to the photovoltaic module PV1, which converts light energy into direct current power and then inputs it into the booster circuit to boost it and treat it. Make effective use.
  • the positive electrode of the photovoltaic module PV1 constitutes the first input terminal, and the negative electrode thereof constitutes the second input terminal.
  • a first output capacitor and a second output capacitor are connected in series between the first output terminal and the second output terminal.
  • the output terminal is usually called a bus
  • each capacitor on the output terminal is called a bus capacitor. Therefore, at the common point between the first output terminal and the second output terminal and the two capacitors, three levels are respectively provided to the subsequent circuit for its use.
  • the boost circuit also includes the following components: an inductor L1, a first controllable switch Q1, and a second controllable switch Q2, first capacitor C1, second capacitor C2, first diode D1, second diode D2, third diode D3 and the fourth diode D4.
  • the inductor L1 is used for the cycle of storing electric energy and releasing electric energy during the working cycle, so as to boost the voltage at the input terminal and output it to the output terminal. The specific working conditions will be described in detail below.
  • the components other than the inductor L1 are connected correspondingly to form the following first branch, second branch, third branch, and fourth branch.
  • the first controllable switch Q1 and the second controllable switch Q2 are connected in series to form a first branch, wherein the first end of the first controllable switch Q1 and the second end of the second controllable switch Q2 are respectively The first end and the second end of the first branch are formed.
  • the first controllable switch Q1 and the second controllable switch Q2 can be transistors or field effect transistors. When it uses a triode, the first end of the first controllable switch Q1 and the second controllable switch Q2 is the collector, and the second end is the emitter; when it uses a field effect transistor, the first controllable switch Q2 The first end of the switch Q1 and the second controllable switch Q2 is the drain, and the second end is the source.
  • the first diode D1 and the second diode D2 are connected in series to form a second branch, wherein the anode of the first diode D1 and the cathode of the second diode D2 respectively form a second branch.
  • the first and second ends of the road are connected in series to form a second branch, wherein the anode of the first diode D1 and the cathode of the second diode D2 respectively form a second branch.
  • the first capacitor C1, the third diode D3 and the second capacitor C2 is connected in series to form a third branch, wherein the anode and cathode of the third diode D3 are connected to one end of the first capacitor C1 and the second capacitor C2, respectively.
  • the other ends respectively constitute the first end and the second end of the third branch.
  • the fourth diode D4 forms a fourth branch, wherein the anode and the cathode of the fourth diode D4 form the first end and the second end of the fourth branch, respectively.
  • the first input end is connected to the first end of the first branch and the first end of the second branch through the inductor L1; the first end of the third branch is connected to the first diode in the second branch The common point between D1 and the second diode D2; the first output terminal is connected to the second end of the second branch; the second input terminal is connected to the first branch, the third branch and the second output terminal .
  • the common point between the first controllable switch Q1 and the second controllable switch Q2 in the first branch is connected to the common point between the first capacitor C1 and the third diode D3 in the second branch.
  • the first end of the fourth branch is connected to the common point between the third diode D3 and the second capacitor C2 in the third branch, and the second end is connected to the first and second ends of the second branch.
  • each branch mainly achieves the following functions.
  • the first branch including a controllable switch is used to control the on and off of each loop in the boost circuit under normal working conditions, so that the inductor L1 is in a state of storing electric energy and releasing electric energy correspondingly, thereby completing the boosting process, Its specific work will be detailed below.
  • the first controllable switch Q1 and the second controllable switch Q2 are various types of transistors, so as to quickly and conveniently control the on and off using electronic signals.
  • the first end and the second end of the second branch point to the input end and the output end, respectively, and the common point of the two diodes therein is connected to the third branch having a capacitive device for connecting the corresponding devices
  • the unidirectional conduction characteristic of the current is formed to prevent the electric energy from fleeing back to the input terminal and causing electric energy loss.
  • the first capacitor C1 is used as a flying capacitor, which is used to store and release electrical energy during normal operation, and also plays a role in boosting the input voltage.
  • the first capacitor C1 and the second capacitor C2 are connected in parallel to the two ends of the first controllable switch Q1 and the second controllable switch Q2, they also have a connection between the first controllable switch Q1 and the second controllable switch.
  • Q2 pressure control the working principle will be detailed below.
  • the fourth branch is used to establish a discharge circuit for the second capacitor C2 in the third branch.
  • Figure 3 shows a schematic diagram of the current loop of the boost circuit when it is powered on.
  • the first controllable switch Q1 and the second controllable switch Q2 are both in the off state, and the first capacitor C1 and the second capacitor C1 and the second capacitor are in the off state.
  • the voltage of the capacitor C2 is zero, so two loops are formed in the boost circuit.
  • loop one is that the input terminal is charged through the inductor L1, the first diode D1, the first capacitor C1, the third diode D3, and the second capacitor C2 is the first capacitor C1 and the second capacitor C2, and the second circuit is The input terminal charges the output capacitors at the output terminal through the inductor L1, the first diode D1, and the second diode D2.
  • the capacitance of the first capacitor C1 and the second capacitor C2 it is preferable to set the capacitance of the first capacitor C1 and the second capacitor C2 to be the same. Therefore, after a certain period of time, the first capacitor C1 and the second capacitor C2 will be respectively charged to half of the input voltage, and at the same time, the sum of the voltages of the capacitors on the output terminal is the input voltage. Since the voltage across the first controllable switch Q1 is equal to the sum of the voltages of the first capacitor C1 and the first diode D1, the voltage across the second controllable switch Q2 is equal to the sum of the voltages of the second capacitor C2 and the third diode D3 , So its withstand voltage is about half of the input voltage.
  • the input voltage reaches 1500V. Its withstand voltage is about 800-900V, which meets the cost requirements of device selection.
  • Figure 4 shows the boost circuit when it is powered off. Schematic diagram of the current loop. It is worth noting that when the circuit is powered off, the output terminal will be discharged through its subsequent circuit. When it is discharged to a voltage lower than the sum of the voltages of the first capacitor C1 and the second capacitor C2, the first capacitor C1 and The second capacitor C2 starts to discharge the output terminal.
  • first capacitor C1 discharges the output terminal through the second diode D2 and the second controllable switch Q2
  • the second capacitor C2 discharges the output terminal through the fourth diode D4 and the second diode D4.
  • the two diodes D2 discharge the output terminal.
  • a second capacitor C2 is provided on the third branch, which cooperates with the first capacitor C1 when it is powered on, and is respectively charged to half of the input voltage, and the two controllable switches can be regarded as being connected to the first capacitor respectively.
  • the capacitor C1 and the second capacitor C2 are connected in parallel, so its voltage is limited by the voltage at both ends of the corresponding capacitor and is within a safe range. This solves the problem that the voltage on the flying capacitor is zero when the power is turned on, which causes the lower arm switch tube to breakdown due to overvoltage.
  • the embodiment of the present application is provided with a fourth branch, which can establish a discharge loop for the second capacitor C2 when the circuit is powered off, thereby improving the safety and stability of circuit operation.
  • Embodiment 1 under normal working conditions will be introduced in detail.
  • the boost circuit works under the condition of duty cycle ⁇ 0.5; on the contrary, when it is greater than the output terminal
  • the boost circuit works in the case of duty cycle>0.5.
  • the boost circuit works with a duty cycle ⁇ 0.5, there will be a state in which both the first controllable switch Q1 and the second controllable switch Q2 are turned off, which corresponds to Figure 6.
  • the boost circuit works with a duty cycle> 0.5, there will be a state where both the first controllable switch Q1 and the second controllable switch Q2 are turned on, which corresponds to FIG. 8.
  • Fig. 5 a schematic diagram of the current loop when the boost circuit is in a normal working state and the first controllable switch Q1 is turned off and the second controllable switch Q2 is turned on is shown.
  • loop one is introduced first, that is, the input terminal charges the inductor L1 and the first capacitor C1 through the inductor L1, the first diode D1, the first capacitor C1, and the second controllable switch Q2, and the inductor L1 and the first capacitor C1 store Energy, and the voltage of the first capacitor C1 rises, the voltage across the inductor L1 is the difference between the input voltage and the voltage across the first capacitor C1 Vpv-Vc1.
  • FIG. 6 a schematic diagram of the current loop when the boost circuit is in a normal working state and the first controllable switch Q1 is turned off and the second controllable switch Q2 is turned off is shown.
  • the electromotive force in the inductor L1 has the opposite polarity to the input voltage, the input voltage and the reverse voltage of the inductor L1 are superimposed to transfer energy to the output terminal.
  • the voltage across the inductor L1 is Vpv-Vbus.
  • Fig. 7 a schematic diagram of the current loop when the boost circuit is in a normal working state and the first controllable switch Q1 is turned on and the second controllable switch Q2 is turned off is shown.
  • the input voltage is superimposed on the reverse voltage of the inductor L1 and the voltage of the first capacitor C1, the second controllable switch Q2 is turned on, and energy is transferred to the output terminal.
  • the voltage across the inductor L1 is Vpv+Vc1-Vbus.
  • FIG. 8 a schematic diagram of the current loop when the boost circuit is in a normal working state and the first controllable switch Q1 is turned on and the second controllable switch Q2 is turned on is shown. At this time, the input voltage is loaded on the inductor L1, and the inductor L1 is in the energy storage state.
  • the cathode of the fourth diode D4 on the fourth branch of the embodiment of the present application is connected to the common point of the first diode D1 and the second diode D2, so that in FIG. 5, there is The other loop, that is, the second capacitor C2 discharges to the first capacitor C1 through the fourth diode D4 to balance the voltage between the two.
  • one end of the first capacitor C1 and the second capacitor C2 are both connected to the second input terminal, that is, their potentials are the same, both are Vbus-, so only when the potential of the other end of the two corresponds to When the difference is the voltage difference of the fourth diode D4, the second capacitor C2 will stop discharging to the first capacitor C1.
  • the first capacitor C1 and the second capacitor C2 are basically balanced.
  • the above-mentioned balance and adjustment are performed in each work cycle. Even if the voltage imbalance occurs in each cycle, the voltage can be rebalanced in the state shown in FIG. 5, thereby realizing the application the goal of.
  • Embodiment 2 of the present application provides a topological structure of a boost circuit.
  • the difference from Embodiment 1 is that it also includes a fifth diode D5; the anode of the fifth diode D5 is connected to the common point between the first output capacitor and the second output capacitor, and the cathode of the fifth diode D5 is connected to the common point between the first output capacitor and the second output capacitor.
  • Figure 10 shows the schematic diagram of the current loop of the second embodiment when the input terminal is not powered and the output terminal is powered. It can be seen that the input terminal, that is, the bus bar will make the first capacitor C1 and the second capacitor C1 and the second capacitor through the fifth diode D5.
  • the capacitor C2 is charged to the half bus voltage respectively, thereby clamping the voltage across the second diode D2 to the half bus voltage, and making the voltages borne by the first diode D1 and the second diode D2 basically evenly distributed, thereby The second diode D2 is protected from breakdown.
  • the fourth diode D4 is connected to the common point of the first diode D1 and the second diode D2, that is, to the cathode of the fifth diode D5,
  • the anode of the fifth diode D5 is connected to the common point between the first output capacitor and the second output capacitor, that is, its potential is clamped at half the bus voltage. Therefore, the maximum potential of the cathode terminal of the fourth diode D4 is half the bus voltage, so that it is within a safe voltage range in any state, and it is prevented from being broken down.
  • the boost circuit of the embodiment of the present application can ensure that the components selected under the normal cost can work safely, stably, and effectively under power-on, power-off, and normal working conditions.
  • Embodiment 3 of the present application provides an inverter device, which includes a front-stage circuit and a rear-stage inverter circuit.
  • the pre-stage circuit adopts the boost circuit described in the above technical solution.
  • the boost circuit is used to boost the voltage input from its input terminal and then output it from the output terminal.
  • the input terminal of the inverter circuit is coupled to the output terminal of the boost circuit for inverting the direct current output from it. Change to alternating current.
  • Embodiment 4 of the present application provides a photovoltaic power generation device, which includes a photovoltaic module, a pre-stage circuit and a post-stage circuit; the pre-stage circuit adopts the boost circuit as described in the above technical solution.
  • the photovoltaic module is coupled to the input terminal of the boost circuit; the boost circuit is used to boost the output voltage of the photovoltaic module and output it to the subsequent circuit from the output terminal.
  • Embodiments 5-7 of the present application provide a photovoltaic power generation system. It includes a plurality of photovoltaic modules, a plurality of pre-stage circuits and a plurality of post-stage circuits; the pre-stage circuit adopts the boost circuit as described in the above technical solution.
  • the photovoltaic module is coupled to the input terminal of the boost circuit; the boost circuit is used to boost the output voltage of the photovoltaic module and output it to the subsequent circuit from the output terminal.
  • embodiment 5 is a string photovoltaic power generation system.
  • the photovoltaic modules correspond to the boost circuit one-to-one, and the electric energy generated by the photovoltaic modules is used as the input of the subsequent circuit after the previous step-up circuit.
  • embodiment 6 is a distributed photovoltaic power generation system. After the electric energy generated by the photovoltaic module passes through multiple pre-stage boost circuits, it is converged by the bus bar and used as the input of the post-stage circuit, that is, the output terminals of multiple boost circuits are connected in parallel. After connecting to the subsequent circuit.
  • the downstream circuit of the photovoltaic power generation system can be connected to a DC circuit or an AC circuit.
  • the output terminal of the booster circuit can be connected to a DC power grid or a DC load.
  • the output end of the booster circuit needs to be connected to the AC power grid or connected to an AC load through an inverter circuit as a subsequent circuit, which is Embodiment 7 (not shown).
  • the input terminal of the inverter circuit is coupled to the output terminal of the boost circuit for inverting the DC power output by the inverter circuit into AC power.

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Abstract

本申请公开了一种升压电路及其装置和系统，所述升压电路第一电容的一端通过第三二极管、第二电容连接至第二输出端，所述第三二极管的阴极还通过第四二极管连接至第一二极管和第二二极管的公共点。采用上述电路后，在上电、下电以及正常工作状态下，均能保证在常规成本下挑选的各器件能够安全、稳定且有效地工作。

Description

一种升压电路及其装置和系统
本申请要求于2019年09月12日提交中国专利局、申请号为201910866995.2、发明名称为“一种升压电路及其装置和系统”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
本申请涉及电路升压技术领域，更具体来讲，涉及一种升压电路及其装置和系统。
 背景技术
目前，光伏发电系统的输入电压在逐步提升，目前已提升到 1500V，考虑到成本及其他因素，光伏逆变器的前级升压电路通常由两电平改为三电平电路。目前，如图 1 所示出的飞跨电容型三电平升压电路在初始上电时，由于飞跨电容上电压为零，会导致下臂开关管 Q2承受全部输入电压，容易导致开关管 Q2 的损坏。
针对上述问题，公布号为 CN108923632A 的中国专利文献提出了一种多电平 Boost 装置，其通过设置依次串联的 N 个分压模块分别与 N 个第一开关一一对应并联，能够实现 N 个第一开关之间的电压分配，进而使 N 个第一开关两端的电压均处于安全范围内，即便启机时输入电压较高而飞跨电容上电压为零，也能够避免第 2 个至第 N 个第一开关因过压而击穿失效的问题。
上述文献一定程度上解决了飞跨电容型三电平升压电路在初始上电时下臂开关管的击穿问题。然而，其仍具有如下缺陷：在升压电路处于正常工作状态下，由于飞跨电容 C1 参与到升压过程，因此其电压值存在较大的波动，从而存在飞跨电容 C1 和分压电容 C21 的电压不平衡的现象。如不对上述不平衡现象作处理，在多次工作周期后，会导致分压电容 C21 的电压值越来越高，飞跨电容 C1 的电压值越来越低，呈现明显的两极分化现象。当分压电容 C21的电压值高于对应的下臂开关管所能承受的耐压值时，将直接导致下臂开关的击穿，从而损坏电路，并造成工作损失。
如何在飞跨电容型三电平升压电路的上电、下电以及正常工作状态下，均能保证在常规成本下挑选的各器件能够安全、稳定且有效地工作，是本案所要解决的问题。
 技术问题
本申请的目的在于解决上述技术问题，提供一种升压电路及其装置和系统。
 技术解决方案
为实现上述目的，本申请的第一方面提供了一种升压电路，包括第一输入端、第二输入端、第一输出端、第二输出端、电感、第一可控开关、第二可控开关、第一电容、第一二极管和第二二极管；其还包括如下器件：第二电容、第三二极管和第四二极管；
所述第一可控开关和第二可控开关串接后构成第一支路，其中，所述第一可控开关的第一端和第二可控开关的第二端分别构成第一支路的第一端和第二端；
所述第一二极管和第二二极管串接后构成第二支路，其中，所述第一二极管的阳极和第二二极管的阴极分别构成第二支路的第一端和第二端；
所述第一电容、第三二极管和第二电容串接后构成第三支路，其中，所述第三二极管的阳极和阴极分别连接第一电容和第二电容的一端，所述第一电容和第二电容的另一端分别构成第三支路的第一端和第二端；
所述第四二极管构成第四支路，其中，所述第四二极管的阳极和阴极分别构成第四支路的第一端和第二端；
所述第一输入端通过所述电感连接第一支路和第二支路的第一端；所述第三支路的第一端连接第二支路中第一二极管和第二二极管间的公共点；所述第一输出端连接第二支路的第二端；所述第二输入端连接第一支路、第三支路和第二输出端；
所述第一支路中第一可控开关和第二可控开关间的公共点连接所述第二支路中第一电容和第三二极管间的公共点；
所述第四支路的第一端连接所述第三支路中第三二极管和第二电容间的公共点，其第二端连接所述第二支路中第一二极管和第二二极管间的公共点。
在某一实施例中：所述第一电容和第二电容的容值相同。
在某一实施例中：所述第一输出端和第二输之间串接有第一输出电容和第二输出电容，所述第一输出电容和第二输出电容的容值相同。
在某一实施例中：还包括第五二极管；所述第五二极管的阳极连接所述第一输出电容和第二输出电容间的公共点，其阴极连接所述第一二极管和第二二极管间的公共点。
为实现上述目的，本申请的第二方面提供了一种逆变装置，其包括后级逆变电路和前级电路；所述前级电路采用如上述技术方案所述的升压电路；
所述升压电路用于将由其输入端输入的电压升压后从所述输出端输出；所述逆变电路的输入端耦合所述升压电路的输出端，用以将其输出的直流电逆变为交流电。
为实现上述目的，本申请的第三方面提供了一种光伏发电装置，其包括光伏组件、前级电路和后级电路；所述前级电路采用如上述技术方案所述的升压电路；
所述光伏组件耦合所述升压电路的输入端；所述升压电路用于将光伏组件的输出电压升压后由其输出端输出至后级电路。
为实现上述目的，本申请的第四方面提供了一种光伏发电系统，其包括多个光伏组件、前级电路和后级电路；所述前级电路采用如上述技术方案所述的升压电路；
所述光伏组件耦合所述升压电路的输入端；所述升压电路用于将光伏组件的输出电压升压后由其输出端输出至后级电路。
在某一实施例中：所述光伏组件与升压电路一一对应。
在某一实施例中：多个升压电路的输出端并联后连接至后级电路。
在某一实施例中：所述后级电路为逆变电路，其输入端耦合所述升压电路的输出端，用以将其输出的直流电逆变为交流电。
 有益效果
相较于现有技术，本申请的有益效果在于：
（1）本申请实施例的升压电路，第一电容通过第三二极管、第二电容连接至第二输出端；在上电时，第二电容与第一电容配合，分别充电至输入电压的一半，而两个可控开关可视为分别与第一电容和第二电容并联，因此其电压受相应电容两端电压的限制而处于安全范围内，解决了上电时飞跨电容上电压为零导致下臂开关管因过压而击穿失效的问题；在对第一可控开关和第二可控开关进行选型时，基本只需采用耐压值稍高于输出电压的一半的器件，符合器件选型的成本要求；
（2）本申请实施例的升压电路，设有第四支路，可在电路下电时为第二电容建立放电回路，提高电路运行的安全性和稳定性；
（3）本申请实施例的升压电路，第四支路上的第四二极管，其阴极连接至所述第一二极管和第二二极管的公共点，在工作周期内，如出现第一电容和第二电容的电压不平衡现象，可使第二电容通过第四二极管向第一电容放电，以平衡二者间的电压；
（4）本申请实施例的升压电路，设有第五二极管，其阳极连接所述第一输出电容和第二输出电容间的公共点，其阴极连接所述第一二极管和第二二极管间的公共点；在输入端无电，输出端有电时，母线会通过第五二极管使第一电容和第二电容分别充电至半母线电压，从而将第二二极管两端的电压钳位在半母线电压，并使第一二极管和第二二极管承受的电压基本均匀分布，从而保护第二二极管不被击穿；
（5）本申请实施例的升压电路，第四二极管连接至所述第一二极管和第二二极管的公共点，即连接到而第五二极管的阴极，而第五二极管的阳极连接至所述第一输出电容和第二输出电容间的公共点，使得第四二极管阴极端的最大电位为半母线电压，使其在任何状态下均处于安全电压范围内，防止其被击穿。
 附图说明
为了更清楚地说明本申请实施例的技术方案，下面对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图是本申请的一些实施例，对于本领域的普通技术人员来说，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图 1 是常规的飞跨电容型三电平升压电路结构图；
图 2 是本申请实施例 1 的升压电路结构图；
图 3 是本申请实施例 1 的升压电路在上电时的电流回路示意图；
图 4 是本申请实施例 1 的升压电路在下电时的电流回路示意图；
图 5 是本申请实施例 1 的升压电路在正常工作状态下，且第一可控开关关断，第二可控开关导通时的电流回路示意图；
图 6 是本申请实施例 1 的升压电路在正常工作状态下，且第一可控开关关断，第二可控开关关断时的电流回路示意图；
图 7 是本申请实施例 1 的升压电路在正常工作状态下，且第一可控开关导通，第二可控开关关断时的电流回路示意图；
图 8 是本申请实施例 1 的升压电路在正常工作状态下，且第一可控开关导通，第二可控开关导通时的电流回路示意图；
图 9 是本申请实施例 2 的升压电路结构图；
图 10 是本申请实施例 2 的升压电路在输入端无电，输出端有电时的电流回路示意图；
图 11 是本申请实施例 3 的逆变装置的结构示意图；
图 12 是本申请实施例 4 的光伏发电装置的结构示意图；
图 13 是本申请实施例 5 的光伏发电系统的结构示意图；
图 14 是本申请实施例 6 的光伏发电系统的结构示意图。
本申请的实施方式
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。显然，所描述的实施例是本申请的优选实施例，且不应被看作对其他实施例的排除。基于本申请实施例，本领域的普通技术人员在不作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
本申请的权利要求书、说明书及上述附图中，除非另有明确限定，如使用术语“第一”、“第二”或“第三”等，都是为了区别不同对象，而不是用于描述特定顺序。本申请的权利要求书、说明书及上述附图中，如使用术语“包括”、“具有”以及它们的变形，意图在于“包含但不限于”。
参照图 2，本申请实施例 1 提供了一种升压电路，具有输入端和输出端。所述输入端包括第一输入端、第二输入端，所述输出端包括第一输出端、第二输出端。
通常来说，本实施例的升压电路可用于各类应用场景，因而其输入端可与各类电源输入装置耦合，以从其接收电源输入。在本文的各实施例中，均以光伏发电领域的应用场景为例介绍，因而输入端耦合光伏组件 PV1，其将光能转化为直流电能后输入升压电路，以将其升压后对其进行有效利用。光伏组件 PV1 的正极构成所述第一输入端，其负极构成所述第二输入端。
此外，本文的各实施例及相应附图中，所述第一输出端和第二输出端之间串接有第一输出电容和第二输出电容。在本申请升压电路应用于光伏发电领域时，通常将输出端称为母线，输出端上的各电容称为母线电容。从而，在第一输出端和第二输出端和两个电容间的公共点，分别向后级电路提供三种电平以供其使用需要。
然而值得说明的是，本申请不限于上述光伏发电领域的应用场景，因此输入端和输出端的耦合形式不局限于本文中各具体实施例的形式。
所述升压电路还包括以下器件：电感 L1、第一可控开关 Q1、第二可控开关 Q2、第一电容 C1、第二电容 C2、第一二极管 D1、第二二极管 D2、第三二极管 D3 和第四二极管 D4。所述电感 L1 用于在工作周期中进行储存电能和释放电能的循环， 以将输入端的电压升压后输出至输出端，其具体工作情况将在下文中详述。
在本申请实施例中，除电感 L1 外的其他各器件对应连接后构成以下的第一支路、第二支路、第三支路和第四支路。
所述第一可控开关 Q1 和第二可控开关 Q2 串接后构成第一支路，其中，所述第一可控开关 Q1 的第一端和第二可控开关 Q2 的第二端分别构成第一支路的第一端和第二端。本实施例中， 所述第一可控开关 Q1 和第二可控开关 Q2 可采用三极管或场效应管。 当其采用三极管时，所述第一可控开关 Q1 和第二可控开关 Q2 的第一端为集电极，第二端为发射极；当其采用场效应管时，所述第一可控开关 Q1 和第二可控开关 Q2 的第一端为漏极，第二端为源极。
所述第一二极管 D1 和第二二极管 D2 串接后构成第二支路，其中，所述第一二极管 D1 的阳极和第二二极管 D2 的阴极分别构成第二支路的第一端和第二端。
所述第一电容 C1、第三二极管 D3 和第二电容 C2 串接后构成第三支路，其中，所述第三二极管 D3 的阳极和阴极分别连接第一电容 C1 和第二电容 C2 的一端，所述第一电容 C1 和第二电容 C2 的另一端分别构成第三支路的第一端和第二端。
所述第四二极管 D4 构成第四支路，其中，所述第四二极管 D4 的阳极和阴极分别构成第四支路的第一端和第二端。
以下介绍升压电路中各支路的具体连接关系：
所述第一输入端通过所述电感 L1 连接第一支路和第二支路的第一端； 所述第三支路的第一端连接第二支路中第一二极管 D1 和第二二极管 D2 间的公共点；所述第一输出端连接第二支路的第二端；所述第二输入端连接第一支路、第三支路和第二输出端。
此外，所述第一支路中第一可控开关 Q1 和第二可控开关 Q2 间的公共点连接所述第二支路中第一电容 C1 和第三二极管 D3 间的公共点。而所述第四支路的第一端连接所述第三支路中第三二极管 D3 和第二电容 C2 间的公共点，其第二端连接所述第二支路中第一二极管 D1 和第二二极管 D2 间的公共点。
通过上述连接以形成本实施例的升压电路后，各支路主要实现如下作用。
包含可控开关的第一支路，用于在正常工作状态下控制升压电路中各回路的通断，使所述电感 L1 对应地处于储存电能和释放电能的状态，从而完成升压过程，其具体工作情况将在下文中详述。本实施例中，所述第一可控开关 Q1 和第二可控开关 Q2 为各类晶体管，以通过电子信号快速且方便地控制器通断。
所述第二支路的第一端和第二端分别指向输入端和输出端，且其内两个二极管的公共点连接具有电容器件的所述第三支路，用以在相应的器件间形成电流的单向导通特性，防止电能反窜回输入端，造成电能损失。
所述第三支路中，第一电容 C1 作为飞跨电容，其用于在正常工作时储存和释放电能，同样起到对输入电压升压的作用。此外，由于第一电容 C1 和第二电容 C2 相当于并联于第一可控开关 Q1 和第二可控开关 Q2 的两端，因此其还具有对第一可控开关 Q1 和第二可控开关 Q2控压的作用，下文将详述其工作原理。
所述第四支路则用于对第三支路中的第二电容 C2 建立放电回路。
以下参照图 3-4，具体介绍本申请实施例 1 在上电和下电时的工作情况。
在图 3 中示出了升压电路在上电时的电流回路示意图，在上电时，第一可控开关 Q1 和第二可控开关 Q2 均处于关断状态，第一电容 C1 和第二电容 C2 的电压均为零，因此在升压电路中形成两个回路。其中，回路一为输入端通过电感 L1、第一二极管 D1、第一电容 C1、第三二极管 D3、第二电容 C2 为第一电容 C1 和第二电容 C2 进行充电，回路二为输入端通过电感L1、第一二极管 D1、第二二极管 D2 为输出端的各输出电容进行充电。本实施例中，优选设置第一电容 C1 和第二电容 C2 的容值相同。因此，在一定时间后，第一电容 C1 和第二电容C2 将分别被充电至输入电压的一半，同时输出端上的各电容的电压和为输入电压。由于第一可控开关 Q1 两端的电压等于第一电容 C1 和第一二极管 D1 的电压和，第二可控开关 Q2 两端的电压等于第二电容 C2 和第三二极管 D3 的电压和，因此其承受的电压均大约为输入电压的一半。从而，在对第一可控开关 Q1 和第二可控开关 Q2 进行选型时，基本只需采用耐压值稍高于输出电压的一半的器件，在本实施例的输入电压达到 1500V 的情况下，其耐压值大约为800-900V，符合器件选型的成本要求。
由于第一电容 C1 和第二电容 C2 在上电和正常工作状态中均储存有电能，因而在电路下电时还必须对其放电，因此在图 4 中示出了升压电路在下电时的电流回路示意图。值得说明的是，当电路下电时，输出端会通过其后级电路进行放电，当其放电至电压低于所述第一电容 C1 和第二电容 C2 的电压和时，第一电容 C1 和第二电容 C2 才开始对输出端进行放电。在图 4 中可以看出，所述第一电容 C1 通过第二二极管 D2、第二可控开关 Q2 对对输出端进行放电，所述第二电容 C2 通过第四二极管 D4、第二二极管 D2 对输出端进行放电。
因此，本申请实施例在第三支路上设置第二电容 C2，其在上电时与第一电容C1 配合，分别充电至输入电压的一半，而两个可控开关可视为分别与第一电容 C1 和第二电容 C2 并联，因此其电压受相应电容两端电压的限制而处于安全范围内，解决了上电时飞跨电容上电压为零导致下臂开关管因过压而击穿失效的问题。此外，本申请实施例设置有第四支路，可在电路下电时为第二电容 C2 建立放电回路，提高电路运行的安全性和稳定性。
以下参照图 5-8，具体介绍实施例 1 在正常工作状态下的工作情况。
首先说明的是，根据输入端的输入电压的值的不同，当其小于输出端所设定的电压值的一半时，升压电路工作于占空比＜0.5 的情况；反之，当其大于输出端所设定的电压值的一半时，升压电路工作于占空比＞0.5 的情况。当升压电路工作于占空比＜0.5 的情况时，其会存在第一可控开关 Q1 和第二可控开关 Q2 均关断的状态，对应于图 6。当升压电路工作于占空比＞0.5 的情况时，其会存在第一可控开关 Q1 和第二可控开关 Q2 均导通的状态，对应于图 8。
在图 5 中，示出了升压电路在正常工作状态下，且第一可控开关 Q1 关断，第二可控开关Q2 导通时的电流回路示意图。其中先介绍回路一，即输入端通过电感 L1、第一二极管 D1、第一电容 C1、第二可控开关 Q2 对电感 L1 和第一电容 C1 进行充电，电感 L1 和第一电容 C1储存能量，且第一电容 C1 的电压上升，电感 L1 两端的电压为输入电压和第一电容 C1 两端的电压差 Vpv-Vc1。
在图 6 中，示出了升压电路在正常工作状态下，且第一可控开关 Q1 关断，第二可控开关Q2 关断时的电流回路示意图。此时，由于电感 L1 内的电动势与输入电压的极性相反，因此输入电压与电感 L1 的反向电压叠加在一起将能量传递到输出端，电感 L1 两端的电压为Vpv-Vbus。
在图 7 中，示出了升压电路在正常工作状态下，且第一可控开关 Q1 导通，第二可控开关Q2 关断时的电流回路示意图。此时，输入电压与电感 L1 反向电压、第一电容 C1 的电压叠加在一起，第二可控开关 Q2 导通，能量传递到输出端，电感 L1 两端的电压为 Vpv+Vc1-Vbus。
此时第一电容 C1 上的电压会下降，第二电容 C2 上的电压会升高。
在图 8 中，示出了升压电路在正常工作状态下，且第一可控开关 Q1 导通，第二可控开关Q2 导通时的电流回路示意图。此时输入电压加载到电感 L1 上，电感 L1 处于储能状态。
从图 5-图 8 中可以看到，无论是占空比＜0.5 的情况还是占空比＞0.5 的情况，均会出现图 7 所示的状态。而在图 7 中即存在第一电容 C1 上的电压下降，第二电容 C2 上的电压升高的情况，也即为上文所述的飞跨电容和分压电容的电压不平衡的现象。
然而，本申请实施例的第四支路上的第四二极管 D4，其阴极连接至所述第一二极管 D1和第二二极管 D2 的公共点，使得在图 5 中，还存在另一回路，即第二电容 C2 通过第四二极管 D4 向第一电容 C1 放电，以平衡二者间的电压。由于本实施例在该状态下，第一电容 C1 和第二电容 C2 的一端均连接至第二输入端，即其电位相同，均为 Vbus-，因此仅在当二者对应的另一端的电位差为第四二极管 D4 的压差时，第二电容 C2 才会停止向第一电容 C1 放电。此时，第一电容 C1 和第二电容 C2 基本达到平衡。本申请实施例在每一工作周期，均进行上述平衡和调整，即便每一周期均存在所述电压不平衡的现象，也能在图 5 所示的状态将其电压再次平衡，从而实现本申请的目的。
参照图 9-10，本申请实施例 2 提供了一种升压电路的拓补结构。其相对于实施例 1 的区别在于还包括第五二极管 D5；所述第五二极管 D5 的阳极连接所述第一输出电容和第二输出电容间的公共点，其阴极连接所述第一二极管 D1 和第二二极管 D2 间的公共点。此外，实施例 2 中，特别规定所述第一输出电容和第二输出电容的容值相同。
值得说明的是，本申请应用于光伏发电领域时，当形成集散式光伏发电系统时，可能存在当母线仍有电，而光伏组件 PV1 无电的情况，此时，母线电压将反灌至升压电路，导致第二二极管 D2 承受母线电压而被击穿。该实施例 2 即旨在解决上述问题。
图 10 中示出了实施例 2 在输入端无电，输出端有电时的电流回路示意图，可以看出，输入端，即母线会通过第五二极管 D5 使第一电容 C1 和第二电容 C2 分别充电至半母线电压，从而将第二二极管 D2 两端的电压钳位在半母线电压，并使第一二极管 D1 和第二二极管 D2 承受的电压基本均匀分布，从而保护第二二极管 D2 不被击穿。
此外，在实施例 2 中，由于第四二极管 D4 连接至所述第一二极管 D1 和第二二极管 D2 的公共点，即连接到而第五二极管 D5 的阴极，而第五二极管 D5 的阳极连接至所述第一输出电容和第二输出电容间的公共点，即其电位被钳位在半母线电压。因而使得第四二极管 D4 阴极端的最大电位为半母线电压，使得其在任何状态下均处于安全电压范围内，防止其被击穿。
从而，本申请实施例的升压电路，在上电、下电以及正常工作状态下，均能保证在常规成本下挑选的各器件能够安全、稳定且有效地工作。
以下通过实施例 3 到实施例 7 介绍上述升压电路的具体应用，当然，其具体的应用场景并不限于这些实施例。
参照图 11，本申请实施例 3 提供了一种逆变装置，其包括前级电路和后级逆变电路。所述前级电路采用上述技术方案所述的升压电路。
所述升压电路用于将由其输入端输入的电压升压后从所述输出端输出，所述逆变电路的输入端耦合所述升压电路的输出端，用以将其输出的直流电逆变为交流电。
参照图 12，本申请实施例 4 提供了一种光伏发电装置，其包括光伏组件、前级电路和后级电路；所述前级电路采用如上述技术方案所述的升压电路。
所述光伏组件耦合所述升压电路的输入端；所述升压电路用于将光伏组件的输出电压升压后由其输出端输出至后级电路。
参照图 13-14，本申请实施例 5-7 提供了一种光伏发电系统。其包括多个光伏组件、多个前级电路和多个后级电路；所述前级电路采用如上述技术方案所述的升压电路。
所述光伏组件耦合所述升压电路的输入端；所述升压电路用于将光伏组件的输出电压升压后由其输出端输出至后级电路。
图 13 中，实施例 5 为组串式光伏发电系统，光伏组件与升压电路一一对应，光伏组件产生的电能经前级升压电路后作为后级电路的输入。图 14 中，实施例 6 为集散式光伏发电系统，光伏组件产生的电能经多个前级升压电路后，经母线汇流后作为后级电路的输入，即多个升压电路的输出端并联后连接至后级电路。
所述光伏发电系统的后级电路可连接直流电路或交流电路。当连接直流电路时，所述升压电路的输出端可连接直流电网，或者连接直流负载。当连接交流电路时，所述升压电路的输出端需通过逆变电路作为后级电路连接交流电网，或者连接交流负载，即为实施例 7（未示出）。所述逆变电路的输入端耦合所述升压电路的输出端，用以将其输出的直流电逆变为交流电。
上述说明书和实施例的描述，用于解释本申请保护范围，但并不构成对本申请保护范围的限定。通过本申请或上述实施例的启示，本领域普通技术人员结合公知常识、本领域的普通技术知识和/或现有技术，通过合乎逻辑的分析、推理或有限的试验可以得到的对本申请实施例或其中一部分技术特征的修改、等同替换或其他改进，均应包含在本申请的保护范围之内。

Claims (10)

  1. 一种升压电路，包括第一输入端、第二输入端、第一输出端、第二输出端、电感、第一可控开关、第二可控开关、第一电容、第一二极管和第二二极管；其特征在于：还包括如下器件：第二电容、第三二极管和第四二极管；
    所述第一可控开关和第二可控开关串接后构成第一支路，其中，所述第一可控开关的第一端和第二可控开关的第二端分别构成第一支路的第一端和第二端；
    所述第一二极管和第二二极管串接后构成第二支路，其中，所述第一二极管的阳极和第二二极管的阴极分别构成第二支路的第一端和第二端；
    所述第一电容、第三二极管和第二电容串接后构成第三支路，其中，所述第三二极管的阳极和阴极分别连接第一电容和第二电容的一端，所述第一电容和第二电容的另一端分别构成第三支路的第一端和第二端；
    所述第四二极管构成第四支路，其中，所述第四二极管的阳极和阴极分别构成第四支路的第一端和第二端；
    所述第一输入端通过所述电感连接第一支路和第二支路的第一端；所述第三支路的第一端连接第二支路中第一二极管和第二二极管间的公共点；所述第一输出端连接第二支路的第二端；所述第二输入端连接第一支路、第三支路和第二输出端；
    所述第一支路中第一可控开关和第二可控开关间的公共点连接所述第二支路中第一电容和第三二极管间的公共点；
    所述第四支路的第一端连接所述第三支路中第三二极管和第二电容间的公共点，其第二端连接所述第二支路中第一二极管和第二二极管间的公共点。
  2. 如权利要求 1 所述的一种升压电路，其特征在于：所述第一电容和第二电容的容值相同。
  3. 如权利要求 1 所述的一种升压电路，其特征在于：所述第一输出端和第二输之间串接有第一输出电容和第二输出电容，所述第一输出电容和第二输出电容的容值相同。
  4. 如权利要求 3 所述的一种升压电路，其特征在于：还包括第五二极管；
    所述第五二极管的阳极连接所述第一输出电容和第二输出电容间的公共点，其阴极连接所述第一二极管和第二二极管间的公共点。。
  5. 一种逆变装置，其特征在于：包括后级逆变电路和前级电路；所述前级电路采用如权利要求 1-4 中任一项所述的升压电路；
    所述升压电路用于将由其输入端输入的电压升压后从所述输出端输出；
    所述逆变电路的输入端耦合所述升压电路的输出端，用以将其输出的直流电逆变为交流电。
  6. 一种光伏发电装置，其特征在于：包括光伏组件、前级电路和后级电路；所述前级电路采用如权利要求 1-4 中任一项所述的升压电路；
    所述光伏组件耦合所述升压电路的输入端；所述升压电路用于将光伏组件的输出电压升压后由其输出端输出至后级电路。
  7. 一种光伏发电系统，其特征在于：包括多个光伏组件、前级电路和后级电路；所述前级电路采用如权利要求 1-4 中任一项所述的升压电路；
    所述光伏组件耦合所述升压电路的输入端；所述升压电路用于将光伏组件的输出电压升压后由其输出端输出至后级电路。
  8. 如权利要求 7 所述的一种光伏发电系统，其特征在于：所述光伏组件与升压电路一一对应。
  9. 如权利要求 7 所述的一种光伏发电系统，其特征在于：多个升压电路的输出端并联后连接至后级电路。
  10. 如权利要求 7 所述的一种光伏发电系统，其特征在于：所述后级电路为逆变电路，其输入端耦合所述升压电路的输出端，用以将其输出的直流电逆变为交流电。
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WO2024174369A1 (zh) * 2023-02-23 2024-08-29 上能电气股份有限公司 升压电路结构、逆变装置及光伏发电系统

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