CN211151522U - Photovoltaic inverter and direct current bus capacitor protection circuit thereof - Google Patents
Photovoltaic inverter and direct current bus capacitor protection circuit thereof Download PDFInfo
- Publication number
- CN211151522U CN211151522U CN201921881937.9U CN201921881937U CN211151522U CN 211151522 U CN211151522 U CN 211151522U CN 201921881937 U CN201921881937 U CN 201921881937U CN 211151522 U CN211151522 U CN 211151522U
- Authority
- CN
- China
- Prior art keywords
- bus capacitor
- voltage
- negative
- positive
- positive bus
- Prior art date
- Legal status (The legal status 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 status listed.)
- Active
Links
Images
Classifications
-
- 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
Landscapes
- Inverter Devices (AREA)
- Protection Of Static Devices (AREA)
Abstract
The utility model provides a direct current bus capacitor protection circuit in a photovoltaic inverter, which comprises a positive bus capacitor overvoltage detection module, a positive bus capacitor controllable voltage-sharing circuit, a negative bus capacitor overvoltage detection module and a negative bus capacitor controllable voltage-sharing circuit, wherein the input end of the positive bus capacitor overvoltage detection module is connected with a positive bus capacitor group, and the output end of the positive bus capacitor overvoltage detection module is connected with the control end of the positive bus capacitor controllable voltage-sharing circuit; the positive bus capacitor overvoltage detection module is connected with the negative bus capacitor bank, and the output end of the negative bus capacitor overvoltage detection module is connected with the control end of the negative bus capacitor controllable voltage-sharing circuit; the controllable voltage-sharing circuit of the negative bus capacitor is connected between one end and the other end of the negative bus capacitor group. Therefore, the direct current bus capacitor can be effectively protected.
Description
[ technical field ] A method for producing a semiconductor device
The utility model relates to an inverter technical field, in particular to photovoltaic inverter and direct current bus-bar capacitance protection circuit thereof.
[ background of the invention ]
In the photovoltaic inverter, a direct current bus is required to be connected with an inversion unit to realize energy decoupling of a direct current side and an alternating current inversion side of the photovoltaic inverter, the direct current bus provides high-amplitude pulsating current to an inversion module, pulsating voltage is generated on the bus, and an electrolytic capacitor is generally applied as a direct current bus capacitor. Because the working voltage of the direct-current bus is high, the voltage-resistant grade capacitor is not easy to select, two electrolytic capacitors with lower voltage resistance and the same voltage resistance and capacity are generally connected in series, and a plurality of groups of electrolytic capacitors are connected in parallel to obtain a capacitor group suitable for the working voltage of the bus. Because the electrolytic capacitors have individual difference and leakage current characteristics, the voltages on the two voltage-dividing capacitors are different, one high voltage and one low voltage are applied, and the electrolytic capacitor with high bearing voltage can exceed the maximum withstand voltage value of the capacitor, thereby causing the damage of the capacitor. In the prior art, resistors with the same resistance value are directly connected in parallel to two series capacitors respectively, so as to achieve the purpose of voltage sharing. However, in a medium and low power photovoltaic inverter, the applied electrolytic capacitor has a large capacity, and voltage sharing can be realized only by connecting a large power resistor in parallel at two ends of the capacitor.
Therefore, there is a need for an improved solution to overcome the above problems.
[ Utility model ] content
An object of the utility model is to provide a photovoltaic inverter and direct current bus-bar capacitance protection circuit thereof, it can effectively protect direct current bus-bar capacitance.
According to one aspect of the present invention, the present invention provides a DC bus capacitor protection circuit in a photovoltaic inverter, the photovoltaic inverter also comprises a positive bus capacitor group, a negative bus capacitor group and an inversion module, wherein one end of the positive bus capacitor group is connected with the positive input end of the inversion module, the other end of the negative bus capacitor bank is connected with a first node, one end of the negative bus capacitor bank is connected with the first node, the other end of the direct current bus capacitor protection circuit is connected with the negative input end of the inversion module, and the direct current bus capacitor protection circuit is characterized by comprising a positive bus capacitor overvoltage detection module, a positive bus capacitor controllable voltage-sharing circuit, a negative bus capacitor overvoltage detection module and a negative bus capacitor controllable voltage-sharing circuit, the input end of the positive bus capacitor overvoltage detection module is connected with the positive bus capacitor bank, and the output end of the positive bus capacitor overvoltage detection module is connected with the control end of the positive bus capacitor controllable voltage-sharing circuit; the positive bus capacitor overvoltage detection module is connected with the negative bus capacitor group, and the output end of the negative bus capacitor overvoltage detection module is connected with the control end of the negative bus capacitor controllable voltage-sharing circuit; the negative bus capacitor controllable voltage-sharing circuit is connected between one end and the other end of the negative bus capacitor group.
According to another aspect of the utility model, the utility model provides a photovoltaic inverter, it includes positive bus-bar capacitance group, negative bus-bar capacitance group, contravariant module to and direct current bus-bar capacitance protection circuit. The direct-current bus capacitor protection circuit comprises a positive bus capacitor overvoltage detection module, a positive bus capacitor controllable voltage-sharing circuit, a negative bus capacitor overvoltage detection module and a negative bus capacitor controllable voltage-sharing circuit, wherein the input end of the positive bus capacitor overvoltage detection module is connected with the positive bus capacitor group, and the output end of the positive bus capacitor overvoltage detection module is connected with the control end of the positive bus capacitor controllable voltage-sharing circuit; the positive bus capacitor overvoltage detection module is connected with the negative bus capacitor group, and the output end of the negative bus capacitor overvoltage detection module is connected with the control end of the negative bus capacitor controllable voltage-sharing circuit; the negative bus capacitor controllable voltage-sharing circuit is connected between one end and the other end of the negative bus capacitor group.
Compared with the prior art, the utility model provides a direct current bus-bar capacitance protection circuit includes bus-bar capacitance overvoltage detection module and equalizer circuit, and bus-bar capacitance overvoltage detection module detects positive half cycle bus-bar capacitance and burden half cycle bus-bar capacitance both ends actual voltage respectively, has surpassed the threshold value of settlement when detecting out bus-bar capacitance both ends voltage, and control equalizer circuit discharges to bus-bar capacitance both ends to effectively protect direct current bus-bar capacitance.
[ description of the drawings ]
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor. Wherein:
fig. 1 is a schematic circuit diagram of a photovoltaic inverter according to an embodiment of the present invention;
fig. 2 is a detailed circuit schematic diagram of a portion of the circuit of the photovoltaic inverter shown in fig. 1 in one embodiment.
[ detailed description ] embodiments
In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.
Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with at least one implementation of the invention is included. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Unless otherwise specified, the terms connected, and connected as used herein mean electrically connected, directly or indirectly.
Fig. 1 is a schematic circuit diagram of a photovoltaic inverter according to an embodiment of the present invention. Please refer to fig. 2, which is a specific circuit diagram of a portion of the circuit of the photovoltaic inverter shown in fig. 1 in one embodiment. The photovoltaic inverter shown in fig. 1 includes an MPPT (Maximum Power Point Tracking) boosting module 110, a positive bus capacitor bank 120, a negative bus capacitor bank 130, a dc bus capacitor protection circuit 140, and an inverter module 150.
The MPPT boost module 110 has an input end connected to the photovoltaic array 200 and an output end connected to an input end of the inverter module 150, and is configured to boost a dc voltage generated by the photovoltaic array (or a photovoltaic power supply) 200 and provide the boosted dc voltage to the inverter module 150. In other embodiments, the MPPT boost module 110 may be replaced with other boost circuits in the prior art.
The inverter module 150 is configured to convert the boosted dc voltage into an ac voltage, and provide the ac voltage to the utility grid 300.
One end of the positive BUS capacitor bank 120 is connected to the positive input BUS + of the inverter module 150, and the other end thereof is connected to the first node BUS _ N. One end of the negative BUS capacitor bank 130 is connected to the first node BUS _ N, and the other end thereof is connected to the negative input terminal BUS of the inverter module 150. And the positive input end BUS + and the negative input end BUS-of the inverter module 150 are connected with the output end of the MPPT boosting module 110.
The positive bus capacitor set 120 includes at least one first capacitor, and each first capacitor of the positive bus capacitor set 120 is connected between one end and the other end of the positive bus capacitor set 120. In the particular embodiment shown in FIG. 2, the positive bus capacitor bank 120 includes four first capacitors C1, C2, C3, and C4. The negative bus capacitor bank 130 comprises at least one second capacitor, and each second capacitor in the negative bus capacitor bank 130 is connected between one end and the other end of the negative bus capacitor bank 130. In the particular embodiment shown in fig. 2, the negative bus capacitor bank 130 includes four second capacitors C5, C6, C7, and C8. In the embodiment shown in fig. 2, the first capacitors C1, C2, C3, C4, and the second capacitors C5, C6, C7, C8 are electrolytic capacitors.
The dc bus capacitor protection circuit 140 includes a positive bus capacitor overvoltage detection module 142, a positive bus capacitor controllable voltage-sharing circuit 144, a negative bus capacitor overvoltage detection module 146, and a negative bus capacitor controllable voltage-sharing circuit 148. The input end of the positive bus capacitor overvoltage detection module 142 is connected to the positive bus capacitor bank 120, and the output end thereof is connected to the control end of the positive bus capacitor controllable voltage-sharing circuit 144; a positive bus capacitance controllable voltage equalizing circuit 144 is connected between one end and the other end of said positive bus capacitance group 120 (i.e. the positive bus capacitance controllable voltage equalizing circuit 144 is connected in parallel with said positive bus capacitance group 120). The input end of the negative bus capacitor overvoltage detection module 146 is connected with the negative bus capacitor bank 130, and the output end thereof is connected with the control end of the negative bus capacitor controllable voltage-sharing circuit 148; the negative bus capacitor controllable voltage equalizing circuit 148 is connected between one end and the other end of the negative bus capacitor bank 130 (i.e., the negative bus capacitor controllable voltage equalizing circuit 148 is connected in parallel with the negative bus capacitor bank 130).
The positive bus capacitor overvoltage detection module 142 is configured to detect voltages at two ends of the positive bus capacitor group 120 (that is, one end and the other end of the positive bus capacitor group 120), and when the voltages at the two ends of the positive bus capacitor group 120 are greater than a first voltage threshold Vp, an output end of the positive bus capacitor overvoltage detection module 142 outputs a first control signal to a control end of the positive bus capacitor controllable voltage-sharing circuit 144 to control the positive bus capacitor controllable voltage-sharing circuit 144 to discharge the positive bus capacitor group 120; when the voltage across the positive bus capacitor group 120 is smaller than the first voltage threshold Vp, the output terminal of the positive bus capacitor overvoltage detection module 142 outputs a second control signal to the control terminal of the positive bus capacitor controllable voltage-sharing circuit 144 to control the positive bus capacitor controllable voltage-sharing circuit 144 to stop discharging the positive bus capacitor group 120.
In the embodiment shown in FIG. 2, the positive bus capacitance over-voltage detection module 142 includes a differential detection circuit 1422 and a first hysteresis comparison circuit 1424. The differential detection circuit 1422 is configured to detect a voltage across the positive BUS capacitor bank 120, and the differential detection circuit 1422 includes resistors R5, R12, R13, R14, and a first operational amplifier U2-a, a negative phase input terminal of the first operational amplifier U2-a is connected to a positive input terminal BUS + of the inverter module 150 through a resistor R13, a positive phase input terminal of the first operational amplifier U2-a is connected to a first node BUS _ N through a resistor R14, and a positive phase input terminal of the first operational amplifier U12 is connected to a negative input terminal BUS-of the inverter module 150 through a resistor R12; the resistor R5 is connected between the negative phase input terminal of the first operational amplifier U2-A and the output terminal thereof. The first hysteresis comparator circuit 1424 comprises resistors R4, R10, R9, R3, R11 and a first comparator U1-a, wherein the resistor R11 is connected between the output end of the first operational amplifier U2-a and the negative phase input end of the first comparator U1-a; the resistor R4 and the resistor R10 are sequentially connected in series between a first voltage source 5V and a negative input end BUS-of the inverter module 150, a connection node O1 between the resistor R4 and the resistor R10 is connected with a positive input end of a first comparator U1-A, the resistor R9 is connected between the positive input end of the first comparator U1-A and an output end thereof, the resistor R3 is connected between the first voltage source 5V and the output end of the first comparator U1-A, and the output end of the first comparator U1-A is connected with an output end BUS _ P _ OVP of the positive BUS capacitor overvoltage detection module 142.
In the embodiment shown in fig. 2, the positive bus capacitor controllable voltage equalizing circuit 144 includes power discharge resistors R2 and R8 connected in series between one end and the other end of the positive bus capacitor group 120, and a first switch, and a control end of the first switch is used as a control end of the positive bus capacitor controllable voltage equalizing circuit 144. In the particular embodiment shown in fig. 2, the first switch is relay K1.
The negative bus capacitor overvoltage detection module 146 is configured to detect voltages at two ends of the negative bus capacitor group 130 (that is, one end and the other end of the negative bus capacitor group 130), and when the voltages at two ends of the negative bus capacitor group 130 are greater than a second voltage threshold Vn, an output end of the negative bus capacitor overvoltage detection module 146 outputs a third control signal to a control end of the negative bus capacitor controllable voltage equalizing circuit 148, so as to control the negative bus capacitor controllable voltage equalizing circuit 148 to discharge the negative bus capacitor group 130; when the voltage at the two ends of the negative bus capacitor bank 130 is smaller than the second voltage threshold Vn, the output end of the negative bus capacitor overvoltage detection module 146 outputs a fourth control signal to the control end of the negative bus capacitor controllable voltage-sharing circuit 148, so as to control the negative bus capacitor controllable voltage-sharing circuit 148 to stop discharging the negative bus capacitor bank 130.
In the embodiment shown in fig. 2, the negative bus capacitance overvoltage detection module 146 includes a voltage sampling circuit 1462 and a second hysteresis comparison circuit 1464. The voltage sampling circuit 1462 is used for sampling the voltage at two ends of the negative BUS capacitor bank 130, the voltage sampling circuit 1462 comprises resistors R23 and R30 which are sequentially connected in series between a first node BUS _ N and a negative input end BUS of the inverter module 150, a connection node O2 between the resistors R23 and R30 is the output end of the voltage sampling circuit 1462, and the voltage on the connection node O2 is the sampling voltage output by the voltage sampling circuit 1462. The second hysteresis comparison circuit 1464 comprises resistors R29, R22, R28, R27, R21 and a second comparator U3-a, wherein the resistors R22 and R29 are sequentially connected in series between a first voltage source 5V and a negative input terminal BUS-of the inverter module 150, the resistor R29 is connected between an output terminal (i.e., a connection node O2) of the voltage sampling circuit 1462 and a negative input terminal of the second comparator U3-a, the resistor R27 is connected between a positive input terminal of the second comparator U3-a and an output terminal thereof, the resistor R21 is connected between the first voltage source 5V and an output terminal of the second comparator U3-a, and an output terminal of the second comparator U3-a is connected to an output terminal BUS _ N _ OVP of the negative BUS overvoltage detection module 146.
In the embodiment shown in fig. 2, the negative bus capacitor controllable voltage equalizing circuit 148 includes power discharge resistors R16 and R20 connected in series between one end and the other end of the negative bus capacitor bank 130, and a second switch, and a control end of the second switch is used as a control end of the negative bus capacitor controllable voltage equalizing circuit 148. In the embodiment shown in fig. 2, the second switch is a transistor Q2.
When the output terminals PV +, PV-of the photovoltaic array 200 have voltage, there will be voltage on the bus capacitors, and the operation mode of the dc bus capacitor protection circuit 140 for protecting the positive bus capacitor bank 120 and the negative bus capacitor bank 130 is described as follows:
for the positive BUS capacitor bank 120, the differential detection circuit 1422 detects the voltages across BUS + and BUS _ N (i.e., detects the voltages across the positive BUS capacitor bank 120) to output a differential detection voltage. When the voltage at the two ends of the positive bus capacitor bank 120 rises during charging, at the positive phase input end of the comparator U1-a, the upper limit value (Vp _ h) of the first threshold voltage Vp is obtained by dividing the voltage by the resistors R4 and R10, and if the differential detection voltage output by the differential detection circuit 1422 is greater than the upper limit value (Vp _ h) of the first threshold voltage Vp, the comparator U1-a outputs the control relay K1 to pull in, and the power resistors R2 and R8 form a closed loop to discharge the two ends of the positive bus capacitor bank 120. When the voltage across the positive bus capacitor bank 120 is discharged and drops, a hysteresis resistor R9 is added to the comparator U1-a, the first threshold voltage Vp of the comparator U1-a becomes low and becomes the lower limit value (Vp _ l) of the first threshold voltage Vp, if the differential detection voltage output by the differential detection circuit 1422 is less than the lower limit value (Vp _ l) of the first threshold voltage Vp, the output of the comparator U1-a is inverted, the relay K1 is turned off, and the positive bus capacitor controllable voltage-sharing circuit 144 stops operating (i.e., stops discharging the positive bus capacitor bank 120).
For the negative BUS capacitor bank 130, the voltage sampling circuit 1462 detects the voltage across BUS _ N and BUS-i.e., detects the voltage across the negative BUS capacitor bank 130 to output a sampled voltage. When the voltage at the two ends of the negative bus capacitor bank 130 rises during charging, at the positive phase input end of the comparator U3-a, the resistors R22 and R28 divide the voltage to obtain the upper limit value (Vn _ h) of the second threshold voltage Vn, and if the sampling voltage output by the voltage sampling circuit 1462 is greater than the upper limit value (Vn _ h) of the second threshold voltage Vn, the comparator U3-a outputs a control triode Q2 to enter a saturation region, and the power resistors R16 and R20 form a closed loop to discharge the two ends of the negative bus capacitor bank 130. When the voltage across the negative bus capacitor bank 130 drops due to discharge, a hysteresis resistor 27 is added to the comparator U3-a, the second threshold voltage Vn of the comparator U3-a becomes low and becomes the lower limit value (Vn _ l) of the second threshold voltage Vn, and if the sampled voltage output by the voltage sampling circuit 1462 is less than the lower limit value (Vn _ l) of the second threshold voltage Vn, the output of the comparator U3-a is inverted, the triode Q2 is turned off, and the negative bus capacitor controllable voltage-sharing circuit 148 stops working (i.e., stops discharging the negative bus capacitor bank 130).
That is to say, in the embodiment shown in fig. 2, the positive bus capacitor overvoltage detection module 142 is configured to detect a voltage across the positive bus capacitor group 120, and when the voltage across the positive bus capacitor group 120 rises and the voltage across the positive bus capacitor group 120 is greater than an upper limit value (Vp _ h) of a first threshold voltage Vp, an output end of the positive bus capacitor overvoltage detection module 142 outputs a first control signal to a control end of the positive bus capacitor controllable voltage equalizing circuit 144 to control the positive bus capacitor controllable voltage equalizing circuit 144 to discharge the positive bus capacitor group 120; when the voltage across the positive bus capacitor group 120 decreases and the voltage across the positive bus capacitor group 120 is smaller than the lower limit value (Vp _ l) of the first threshold voltage Vp, the output terminal of the positive bus capacitor overvoltage detection module 142 outputs a second control signal to the control terminal of the positive bus capacitor controllable voltage-sharing circuit 144 to control the positive bus capacitor controllable voltage-sharing circuit 144 to stop discharging the positive bus capacitor group 120. The negative bus capacitor overvoltage detection module 146 is configured to detect voltages at two ends of the negative bus capacitor group 130, and when the voltages at two ends of the negative bus capacitor group 130 increase and the voltages at two ends of the negative bus capacitor group 130 are greater than an upper limit value (Vn _ h) of the second threshold voltage Vn, an output end of the negative bus capacitor overvoltage detection module 146 outputs a third control signal to a control end of the negative bus capacitor controllable voltage-sharing circuit 148, so as to control the negative bus capacitor controllable voltage-sharing circuit 148 to discharge the negative bus capacitor group 130; when the voltage across the negative bus capacitor bank 130 decreases and the voltage across the negative bus capacitor bank 130 is smaller than the lower limit (Vn _ l) of the second threshold voltage Vn, the output end of the negative bus capacitor overvoltage detection module 146 outputs a fourth control signal to the control end of the negative bus capacitor controllable voltage-sharing circuit 148 to control the negative bus capacitor controllable voltage-sharing circuit 148 to stop discharging the negative bus capacitor bank 130.
To sum up, the utility model provides a photovoltaic inverter and direct current bus capacitance protection circuit thereof, direct current bus capacitance protection circuit 140 includes positive bus capacitance overvoltage detection module 142, the controllable equalizer circuit of positive bus capacitance 144, the overvoltage detection module of negative bus capacitance 146, the controllable equalizer circuit of negative bus capacitance 148.
The positive bus capacitor overvoltage detection module 142 and the negative bus capacitor overvoltage detection module 146 respectively detect actual voltages at two ends of the positive bus capacitor group 120 and the negative bus capacitor group 130, when it is detected that the voltages at two ends of the bus capacitor groups 120 and 130 exceed a set upper threshold voltage limit, the corresponding voltage equalizing circuits 144 and 148 are controlled to discharge at two ends of the bus capacitor groups 120 and 130, a certain hysteresis loop is arranged, and when it is detected that the voltages at two ends of the discharged bus capacitor groups 120 and 130 fall to the set lower threshold voltage limit, the corresponding voltage equalizing circuits 144 and 148 are controlled to stop working, so that the electrolytic capacitors can be effectively protected. Because the bus voltage of the photovoltaic inverter can be reduced after the photovoltaic inverter is actually connected to the grid for operation, the voltage-sharing circuit does not work when the photovoltaic inverter is connected to the grid for power generation, energy consumption is avoided, the power generation efficiency of the photovoltaic inverter is improved, and internal heating of the photovoltaic inverter is avoided. The utility model provides a direct current bus-bar capacitance protection circuit is pure hardware circuit, does not have complicated control circuit, even when photovoltaic inverter internal control circuit trouble, also can be to generating line electrolytic capacitor protection.
In the present invention, the terms "connected", "connecting", and the like denote electrical connections, and, unless otherwise specified, may denote direct or indirect electrical connections.
It should be noted that those skilled in the art can make modifications to the embodiments of the present invention without departing from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not to be limited to the specific embodiments described above.
Claims (10)
1. A DC bus capacitor protection circuit in a photovoltaic inverter, the photovoltaic inverter also comprises a positive bus capacitor group, a negative bus capacitor group and an inversion module, one end of the positive bus capacitor group is connected with the positive input end of the inversion module, the other end is connected with a first node, one end of the negative bus capacitor group is connected with the first node, the other end is connected with the negative input end of the inversion module, the DC bus capacitor protection circuit is characterized in that,
the direct current bus capacitor protection circuit comprises a positive bus capacitor overvoltage detection module, a positive bus capacitor controllable voltage-sharing circuit, a negative bus capacitor overvoltage detection module and a negative bus capacitor controllable voltage-sharing circuit,
the input end of the positive bus capacitor overvoltage detection module is connected with the positive bus capacitor bank, and the output end of the positive bus capacitor overvoltage detection module is connected with the control end of the positive bus capacitor controllable voltage-sharing circuit; the positive bus capacitor controllable voltage-sharing circuit is connected between one end and the other end of the positive bus capacitor group,
the input end of the negative bus capacitor overvoltage detection module is connected with the negative bus capacitor bank, and the output end of the negative bus capacitor overvoltage detection module is connected with the control end of the negative bus capacitor controllable voltage-sharing circuit; the negative bus capacitor controllable voltage-sharing circuit is connected between one end and the other end of the negative bus capacitor group.
2. The DC bus capacitance protection circuit in a photovoltaic inverter of claim 1,
the positive bus capacitor overvoltage detection module is used for detecting voltages at two ends of the positive bus capacitor bank, and when the voltages at the two ends of the positive bus capacitor bank are larger than a first voltage threshold value, the output end of the positive bus capacitor overvoltage detection module outputs a first control signal to the control end of the positive bus capacitor controllable voltage-sharing circuit so as to control the positive bus capacitor controllable voltage-sharing circuit to discharge the positive bus capacitor bank; when the voltage at the two ends of the positive bus capacitor group is smaller than the first voltage threshold, the output end of the positive bus capacitor overvoltage detection module outputs a second control signal to the control end of the positive bus capacitor controllable voltage-sharing circuit to control the positive bus capacitor controllable voltage-sharing circuit to stop discharging the positive bus capacitor group,
the negative bus capacitor overvoltage detection module is used for detecting voltages at two ends of the negative bus capacitor group, and when the voltages at the two ends of the negative bus capacitor group are larger than a second voltage threshold value, the output end of the negative bus capacitor overvoltage detection module outputs a third control signal to the control end of the negative bus capacitor controllable voltage-sharing circuit so as to control the negative bus capacitor controllable voltage-sharing circuit to discharge the negative bus capacitor group; when the voltage at the two ends of the negative bus capacitor bank is smaller than the second voltage threshold, the output end of the negative bus capacitor overvoltage detection module outputs a fourth control signal to the control end of the negative bus capacitor controllable voltage-sharing circuit so as to control the negative bus capacitor controllable voltage-sharing circuit to stop discharging the negative bus capacitor bank.
3. The DC bus capacitance protection circuit in a photovoltaic inverter of claim 2,
the positive bus capacitor overvoltage detection module is used for detecting voltages at two ends of the positive bus capacitor bank, and when the voltages at the two ends of the positive bus capacitor bank are increased and the voltages at the two ends of the positive bus capacitor bank are larger than the upper limit value of a first threshold voltage, the output end of the positive bus capacitor overvoltage detection module outputs a first control signal to the control end of the positive bus capacitor controllable voltage-sharing circuit so as to control the positive bus capacitor controllable voltage-sharing circuit to discharge the positive bus capacitor bank; when the voltage at the two ends of the positive bus capacitor group is reduced and the voltage at the two ends of the positive bus capacitor group is smaller than the lower limit value of the first threshold voltage, the output end of the positive bus capacitor overvoltage detection module outputs a second control signal to the control end of the positive bus capacitor controllable voltage-sharing circuit to control the positive bus capacitor controllable voltage-sharing circuit to stop discharging the positive bus capacitor group,
the negative bus capacitor overvoltage detection module is used for detecting voltages at two ends of the negative bus capacitor group, and when the voltages at the two ends of the negative bus capacitor group are increased and the voltages at the two ends of the negative bus capacitor group are larger than the upper limit value of a second threshold voltage, the output end of the negative bus capacitor overvoltage detection module outputs a third control signal to the control end of the negative bus capacitor controllable voltage-sharing circuit so as to control the negative bus capacitor controllable voltage-sharing circuit to discharge the negative bus capacitor group; when the voltage at the two ends of the negative bus capacitor bank is reduced and the voltage at the two ends of the negative bus capacitor bank is smaller than the lower limit value of the second threshold voltage, the output end of the negative bus capacitor overvoltage detection module outputs a fourth control signal to the control end of the negative bus capacitor controllable voltage-sharing circuit so as to control the negative bus capacitor controllable voltage-sharing circuit to stop discharging the negative bus capacitor bank.
4. The DC bus capacitance protection circuit in a photovoltaic inverter according to claim 2 or 3,
the positive bus capacitor group comprises at least one first capacitor, and each first capacitor in the positive bus capacitor group is connected between one end and the other end of the positive bus capacitor group;
the negative bus capacitor bank comprises at least one second capacitor, and each second capacitor in the negative bus capacitor bank is connected between one end and the other end of the negative bus capacitor bank.
5. The DC bus capacitance protection circuit in a photovoltaic inverter of claim 4,
the positive bus capacitor controllable voltage-sharing circuit comprises a first power discharge resistor and a first switch which are sequentially connected in series between one end and the other end of the positive bus capacitor group, and the control end of the first switch is used as the control end of the positive bus capacitor controllable voltage-sharing circuit;
the negative bus capacitor controllable voltage-sharing circuit comprises a second power discharge resistor and a second switch which are sequentially connected in series between one end and the other end of the negative bus capacitor bank, and the control end of the second switch is used as the control end of the negative bus capacitor controllable voltage-sharing circuit.
6. The DC bus capacitance protection circuit in a photovoltaic inverter of claim 5,
the first capacitor and the second capacitor are electrolytic capacitors;
the first switch is a relay;
the second switch is a triode.
7. The DC bus capacitance protection circuit in a photovoltaic inverter of claim 3,
the positive bus capacitance overvoltage detection module comprises a differential detection circuit and a first hysteresis comparison circuit,
the differential detection circuit comprises resistors R5, R12, R13, R14 and a first operational amplifier, wherein the negative phase input end of the first operational amplifier is connected with the positive electrode input end of the inversion module through a resistor R13, the positive phase input end of the first operational amplifier is connected with a first node through a resistor R14, and the positive phase input end of the first operational amplifier is connected with the negative electrode input end of the inversion module through a resistor R12; a resistor R5 is connected between the negative phase input of the first operational amplifier and its output,
the first hysteresis comparison circuit comprises resistors R4, R10, R9, R3, R11 and a first comparator, wherein the resistor R11 is connected between the output end of the first operational amplifier and the negative phase input end of the first comparator; the resistor R4 and the resistor R10 are sequentially connected in series between a first voltage source and the negative input end of the inverter module, a connecting node between the resistor R4 and the resistor R10 is connected with the positive input end of the first comparator, the resistor R9 is connected between the positive input end of the first comparator and the output end of the first comparator, the resistor R3 is connected between the first voltage source and the output end of the first comparator, and the output end of the first comparator is connected with the output end of the positive bus capacitor overvoltage detection module.
8. The DC bus capacitance protection circuit in a photovoltaic inverter of claim 3,
the negative bus capacitor overvoltage detection module comprises a voltage sampling circuit and a second hysteresis comparison circuit,
the voltage sampling circuit comprises resistors R23 and R30 which are sequentially connected in series between a first node and the negative electrode input end of the inversion module, a connecting node between the resistors R23 and R30 is the output end of the voltage sampling circuit,
the second hysteresis comparison circuit comprises resistors R29, R22, R28, R27, R21 and a second comparator, wherein a resistor R22 and a resistor R29 are sequentially connected in series between a first voltage source and the negative input end of the inverter module, a resistor R29 is connected between the output end of the voltage sampling circuit and the negative input end of the second comparator, a resistor R27 is connected between the positive input end of the second comparator and the output end of the second comparator, a resistor R21 is connected between the first voltage source and the output end of the second comparator, and the output end of the second comparator is connected with the output end of the negative bus capacitor overvoltage detection module.
9. A photovoltaic inverter, characterized in that it comprises a positive bus capacitor bank, a negative bus capacitor bank, an inverter module, and a dc bus capacitor protection circuit according to claims 1-8.
10. The photovoltaic inverter of claim 9, further comprising a boost module,
the input end of the boosting module is connected with the photovoltaic array, the output end of the boosting module is connected with the input end of the inversion module, and the boosting module is used for boosting the direct-current voltage generated by the photovoltaic array and supplying the boosted direct-current voltage to the inversion module;
the inversion module is used for converting the boosted direct-current voltage into alternating-current voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921881937.9U CN211151522U (en) | 2019-11-04 | 2019-11-04 | Photovoltaic inverter and direct current bus capacitor protection circuit thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921881937.9U CN211151522U (en) | 2019-11-04 | 2019-11-04 | Photovoltaic inverter and direct current bus capacitor protection circuit thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211151522U true CN211151522U (en) | 2020-07-31 |
Family
ID=71768820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921881937.9U Active CN211151522U (en) | 2019-11-04 | 2019-11-04 | Photovoltaic inverter and direct current bus capacitor protection circuit thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211151522U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112072911A (en) * | 2020-09-11 | 2020-12-11 | 广东美的暖通设备有限公司 | Bus capacitor voltage regulating circuit, frequency converter and air conditioner |
| CN113225016A (en) * | 2021-04-26 | 2021-08-06 | 科华数据股份有限公司 | Voltage-sharing method and device for parasitic capacitance of photovoltaic panel and terminal equipment |
| CN114597867A (en) * | 2022-04-01 | 2022-06-07 | 杭州利沃得电源有限公司 | Overcurrent protection device and three-phase inverter |
| WO2024093227A1 (en) * | 2022-10-31 | 2024-05-10 | 广东美的制冷设备有限公司 | Electronic device, control method and apparatus therefor, and storage medium |
-
2019
- 2019-11-04 CN CN201921881937.9U patent/CN211151522U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112072911A (en) * | 2020-09-11 | 2020-12-11 | 广东美的暖通设备有限公司 | Bus capacitor voltage regulating circuit, frequency converter and air conditioner |
| CN113225016A (en) * | 2021-04-26 | 2021-08-06 | 科华数据股份有限公司 | Voltage-sharing method and device for parasitic capacitance of photovoltaic panel and terminal equipment |
| CN114597867A (en) * | 2022-04-01 | 2022-06-07 | 杭州利沃得电源有限公司 | Overcurrent protection device and three-phase inverter |
| CN114597867B (en) * | 2022-04-01 | 2023-12-08 | 杭州利沃得电源有限公司 | Overcurrent protection device and three-phase inverter |
| WO2024093227A1 (en) * | 2022-10-31 | 2024-05-10 | 广东美的制冷设备有限公司 | Electronic device, control method and apparatus therefor, and storage medium |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN211151522U (en) | Photovoltaic inverter and direct current bus capacitor protection circuit thereof | |
| CN107612405B (en) | Photovoltaic solid-state transformer | |
| CN104868766A (en) | Inversion device and AC power supply system applying same | |
| CN104333215B (en) | A kind of method and device for inhibiting inverter frequent start-stop | |
| US9614458B1 (en) | Methods for determining maximum power point tracking in power converters | |
| CN105743378B (en) | A kind of T-shaped three-level inverter parallel system and its decoupling control method | |
| CN108900078B (en) | Flying capacitor type three-level converter and control method thereof | |
| CN104333213A (en) | Protecting method for output overvoltage of PV array, device and system | |
| CN204244107U (en) | Grid-connecting apparatus | |
| CN112769102A (en) | Photovoltaic inverter and direct current bus capacitor protection circuit thereof | |
| CN109449997B (en) | Modular high-power shore power supply system | |
| TW201717534A (en) | Power conversion device and control method thereof | |
| US11683008B2 (en) | Photovoltaic inverter, photovoltaic system, and method for controlling discharging | |
| CN102420437A (en) | Multi-filtering single-phase photovoltaic grid-connected power generating system | |
| Lin et al. | Ripple current effect on output power of solar-cell panel | |
| CN109274281B (en) | Suppression system and suppression method for low-frequency input pulsating current of photovoltaic grid-connected inverter | |
| CN111525887A (en) | Grounding detection circuit and method for non-isolated photovoltaic inverter | |
| CN106353953A (en) | Flashlight module and flashlight power module | |
| CN202628423U (en) | Solar energy photovoltaic water pump system | |
| CN215180589U (en) | Three-level inverter power module detection circuit | |
| CN209446692U (en) | A kind of detection circuit and DC Electronic Loads for grid-connecting apparatus | |
| CN114400913A (en) | Photovoltaic inverter and photovoltaic grid-connected inverter system applying same | |
| Nisha et al. | DC link embedded impedance source inverter for photovoltaic system | |
| CN105262435A (en) | Pre-assembled substation room of photovoltaic power station | |
| CN212367122U (en) | Power-on and power-off control device of energy storage inverter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |