CN214125146U

CN214125146U - Capacitive load high-voltage starting current-impact-preventing circuit

Info

Publication number: CN214125146U
Application number: CN202120160612.2U
Authority: CN
Inventors: 吴磊; 唐德平; 李中涛; 余峰
Original assignee: Hefei Kewei Power System Co ltd
Current assignee: Cowell Technology Co ltd
Priority date: 2021-01-20
Filing date: 2021-01-20
Publication date: 2021-09-03
Anticipated expiration: 2031-01-20

Abstract

The utility model discloses a current surge circuit is prevented in capacitive load high pressure start-up, including high voltage direct current power supply, controller ARM1, switch K1, switch K2, resistance R1 and capacitive load, the positive end of high voltage direct current power supply is connected with switch K1's one end, switch K2's one end and controller ARM 1's IO control port respectively, the other end of switch K1 is connected with resistance R1's one end, and switch K2's the other end, resistance R1's the other end, capacitive load's one end and controller ARM 1's sampling port all are connected together, and high voltage direct current power supply's negative terminal is connected with capacitive load's the other end; the utility model has the advantages that: the automatic soft start of the capacitive load is realized, and the current impact is reduced.

Description

Capacitive load high-voltage starting current-impact-preventing circuit

Technical Field

The utility model relates to a current surge defense field, more specifically relate to a capacitive load high voltage starts prevents current surge circuit.

Background

Under general conditions, the output of a direct current power supply is provided with a soft start circuit, and when a capacitive load is connected and a large voltage difference exists between the output of the power supply and the two ends of the load, current impact can be effectively avoided through the soft start circuit. However, this circuit has a certain limitation, i.e. it needs to be soft-started first, and generally consists of a relay and a current-limiting resistor of a soft-start loop, and when the output voltage of the dc power supply is substantially consistent with the load voltage, the switching device in the main loop can be closed. Therefore, before the load is pulled, the power supply needs to complete the soft start process, and the next operation can be performed. Thus, the efficiency of the operation is greatly reduced. And in some cases such soft start circuits are not suitable.

In the field of photovoltaic, the starting principle of a class of inverters is that when the fact that the direct-current voltage of an input end reaches a certain voltage value V is detected, it is judged that the photovoltaic energy can allow the inverters to run for power generation. Under the condition, the relay in the main loop is directly closed, and the rapid operation is carried out, so that the energy load is pulled. The input side of the inverter has a large bus capacitance, the inverter belongs to a capacitive load, and when a voltage V is directly applied across the capacitance, a very large current pulse is generated due to a sufficiently small internal resistance. However, when the photovoltaic cell is actually connected to work, due to the characteristics of the photovoltaic cell, even if the output of the cell is short-circuited, the output current can be effectively inhibited, so that certain damage can not be caused to devices in a main loop.

For the above cases, although the photovoltaic cell has a current limiting characteristic when actually connected to the photovoltaic cell, energy supply only through the photovoltaic cell cannot be realized in the actual device development stage. A test power supply is needed to provide energy for various functions and performance verification. In order to be closer to the actual working condition of the photovoltaic cell, after the inverter detects that the external high-voltage direct current voltage is built and stabilized, the input side relay is closed again, and the photovoltaic cell is operated immediately. The process belongs to the natural charging and discharging process of the capacitor at the output end of the high-voltage direct-current power supply to the capacitor at the input end of the inverter, and the current impact completely depends on the voltage difference value and the line impedance. Therefore, the current surge is typically several tens of times higher than the current of the main loop device. In this case, it is necessary to design a device connected between the high voltage power supply and the capacitive load for automatically suppressing the current surge and preventing the device from being damaged during the test.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem that will solve lies in lacking the device of automatic suppression electric current impact between prior art high voltage power supply and the capacitive load.

The utility model discloses a following technical means realizes solving above-mentioned technical problem: the utility model provides a capacitive load high pressure starts and prevents electric current rush circuit, includes high voltage direct current power supply, controller ARM1, switch K1, switch K2, resistance R1 and capacitive load, the positive end of high voltage direct current power supply is connected with the one end of switch K1, the one end of switch K2 and controller ARM 1's IO control port respectively, the other end of switch K1 is connected with resistance R1's one end, and the other end of switch K2, the other end of resistance R1, capacitive load's one end and controller ARM 1's sampling port all are connected together, and the negative end of high voltage direct current power supply is connected with capacitive load's the other end.

The utility model discloses in capacitive load's switch closure in the twinkling of an eye, because electric capacity is equivalent to the short circuit, capacitive load terminal voltage amplitude reduces immediately, then through switch K1 and resistance R1 return circuit for capacitive load's electric capacity charge, after charging, capacitive load terminal voltage accomplishes the rebound rapidly, controller ARM1 detects high voltage direct current power supply output high pressure and capacitive load terminal voltage after the rebound, thereby control closed switch K2 realizes automatic soft-start, reduce the electric current and strike.

Further, the capacitive load comprises a switch K3 and a capacitor C1, one end of the switch K3 is connected with the sampling port of the controller ARM1, the other end of the resistor R1 and the other end of the switch K2, the other end of the switch K3 is connected with one end of the capacitor C1, and the other end of the capacitor C1 is connected with the negative end of the high-voltage direct-current power supply.

Further, the switch K1 and the switch K2 are both dc relays.

Further, the switch K1 is a relay for the dc current 100A.

Further, the resistance of the resistor R1 is 5 Ω.

Further, the output voltage of the high-voltage direct-current power supply is 700V.

Further, the controller ARM1 is of an ARM922T model.

The utility model has the advantages that: the utility model discloses in capacitive load's switch closure in the twinkling of an eye, because electric capacity is equivalent to the short circuit, capacitive load terminal voltage amplitude reduces immediately, then through switch K1 and resistance R1 return circuit for capacitive load's electric capacity charge, after charging, capacitive load terminal voltage accomplishes the rebound rapidly, controller ARM1 detects high voltage direct current power supply output high pressure and capacitive load terminal voltage after the rebound, thereby control closed switch K2 realizes automatic soft-start, reduce the electric current and strike.

Drawings

FIG. 1 is a schematic diagram of a capacitive load high-voltage start current surge prevention circuit according to an embodiment of the present invention;

fig. 2 is a schematic diagram of voltage change during the working process of the capacitive load high-voltage start current surge prevention circuit disclosed in the embodiment of the present invention;

fig. 3 is a schematic diagram of voltage variation during soft start of capacitive load of a capacitive load high-voltage start current surge protection circuit according to an embodiment of the present invention.

Detailed Description

To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the embodiments of the present invention are combined to clearly and completely describe the technical solution in the embodiments of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

As shown in FIG. 1, the capacitive load high-voltage starting current surge preventing circuit comprises a high-voltage direct current power supply, a controller ARM1, a switch K1, a switch K2, a resistor R1 and a capacitive load, wherein the positive end of the high-voltage direct current power supply is connected with one end of the switch K1, one end of the switch K2 and an IO control port of the controller ARM1 respectively, the other end of the switch K1 is connected with one end of the resistor R1, the other end of the switch K2, the other end of the resistor R1, one end of the capacitive load and a sampling port of the controller ARM1 are connected together, and the negative end of the high-voltage direct current power supply is connected with the other end of the capacitive load. The capacitive load comprises a switch K3 and a capacitor C1, one end of the switch K3 is connected with a sampling port of a controller ARM1, the other end of a resistor R1 and the other end of a switch K2, the other end of the switch K3 is connected with one end of a capacitor C1, and the other end of the capacitor C1 is connected with the negative end of a high-voltage direct-current power supply. In this embodiment, the switch K1 and the switch K2 are both dc relays. The switch K1 is a relay for dc current 100A. The resistance of the resistor R1 is 5 omega. The output voltage of the high-voltage direct-current power supply is 700V. The controller ARM1 is of the type ARM 922T.

Referring to fig. 2 in combination with fig. 1, the high voltage dc power supply outputs a high voltage V1, the controller ARM1 controls the switch K1 to be in a closed state, the controller ARM1 controls the switch K2 to be in an open state, the voltage V2 at the input end of the capacitive load is substantially equal to the voltage V1 at the output end of the high voltage dc power supply, when the capacitive load detects that the voltage V2 at the input end reaches a self-start condition, the internal switch K3 is closed, at the instant when the switch K3 is closed, the voltage V2 at the input end drops to V2, the controller ARM1 detects that the value V2 meets the condition, the control logic determination is started, when the voltage V2 rises again and Δ V1-V2 reaches a soft-start end determination condition, that the capacitor C1 is charged, the controller ARM1 controls the switch K2 to be closed, and at the same time, the switch K1 is controlled to be opened. So far, the automatic soft start control is completed, because the charging current of the capacitor C1 is limited through the resistor R1, and the charging time can be basically controlled within 100ms through the resistance value of the conditional resistor R1. Therefore, the whole control process can be completed within 150ms, and the load can be started to load immediately after the switch K3 is closed, so that the operation is not influenced. According to the capacitance of the load input end, the current suppression amplitude and the charging time can be confirmed through the resistance of the conditional resistor R1, and the safety of a main loop device and the load loading speed are met.

As shown in fig. 3, the load start condition is that the input voltage reaches 650V or more, and the dc output voltage of the high-voltage dc power supply is set to 700V. The switch K1 selects a direct current 100A relay, the resistance value of the resistor R1 is 5 omega, the switch K2 selects a direct current relay, and the current level is consistent with the maximum current of the direct current power supply. After the high-voltage direct-current power supply is started, the output voltage gradually rises according to the set slope, when the output voltage V1 reaches 650V, the voltage of the capacitive load input end V2 synchronously reaches 650V, the load judges that the operation condition is met, the switch K3 is immediately closed, the voltage of the capacitive load input end V2 is reduced and then rises, and when the voltage delta V is less than or equal to 2V, the switch K2 is closed. The high-voltage direct-current power supply supplies power to the load through a switch K2 loop, and the load is normally started to pull the load.

It should be noted that the present invention only protects the hardware circuit architecture, and does not protect the control logic of the circuit, and the above description of the control logic is only for facilitating understanding of the solution of the present application.

Through the technical scheme, the utility model provides a capacitive load high pressure starts and prevents electric current rush circuit, in the switch closure of capacitive load in the twinkling of an eye, because electric capacity is equivalent to the short circuit, capacitive load terminal voltage amplitude reduces immediately, then the electric capacity that gives capacitive load through switch K1 and resistance R1 return circuit charges, after charging, capacitive load terminal voltage accomplishes the rebound rapidly, controller ARM1 detects high voltage direct current power supply output high pressure and capacitive load terminal voltage after the rebound, thereby control closed switch K2, realize automatic soft-up, reduce the electric current rush.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims

1. The utility model provides a capacitive load high pressure starts and prevents current rush circuit which characterized in that, includes high voltage direct current power supply, controller ARM1, switch K1, switch K2, resistance R1 and capacitive load, the positive terminal of high voltage direct current power supply is connected with the one end of switch K1, the one end of switch K2 and controller ARM 1's IO control port respectively, the other end of switch K1 is connected with the one end of resistance R1, the other end of switch K2, the other end of resistance R1, the one end of capacitive load and the sampling port of controller ARM1 all are connected to together, and the negative terminal of high voltage direct current power supply is connected with the other end of capacitive load.

2. The circuit for preventing current surge during high-voltage startup of capacitive load according to claim 1, wherein the capacitive load comprises a switch K3 and a capacitor C1, one end of the switch K3 is connected to a sampling port of a controller ARM1, the other end of a resistor R1 and the other end of a switch K2, the other end of the switch K3 is connected to one end of a capacitor C1, and the other end of the capacitor C1 is connected to the negative end of the high-voltage direct-current power supply.

3. The circuit of claim 1, wherein the switch K1 and the switch K2 are dc relays.

4. The circuit of claim 3, wherein the switch K1 is a relay for DC 100A.

5. The circuit of claim 1, wherein the resistance R1 is 5 Ω.

6. The capacitive load high-voltage startup current surge prevention circuit according to claim 1, wherein the output voltage of the high-voltage direct current power supply is 700V.

7. The capacitive load high-voltage startup current surge prevention circuit as claimed in claim 1, wherein said controller ARM1 is of type ARM 922T.