A black start circuit for suppressing oscillation in energy storage system

Abstract

The invention discloses a black start circuit for suppressing oscillation in an energy storage system. The circuit comprises an energy storage battery, a soft start resistor, a first capacitor and an isolation operational amplifier. The soft start resistor, the first capacitor and the isolation operational amplifier are sequentially connected in series between the positive electrode and the negative electrode of the energy storage battery. The invention is characterized in that a PMOS tube is connected in series between the energy storage battery and the soft start resistor, a slave control circuit is connected between the PMOS tube and the negative electrode of the energy storage battery, and the slave control circuit is used to control the on and off of the PMOS tube; a signal input end of the slave control circuit is connected to a main control circuit through an isolation optical coupler, and the main control circuit is connected to an auxiliary power supply, and the auxiliary power supply is used to supply power to the main control circuit and the isolation optical coupler respectively; wherein the main control circuit is used to generate a control signal, and transmit the control signal to the slave control circuit through the isolation optical coupler, the slave control circuit controls the PMOS tube to be closed, and then the energy storage battery charges the first capacitor steadily, so as to avoid the soft start oscillation of the system during the black start process.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a black start circuit for suppressing oscillation in an energy storage system. Background Art

[0002] Energy storage systems play an important role in the power system. They are used to store and release electrical energy to balance the grid load and improve energy efficiency.

[0003] The black start circuit is used in energy storage systems where all external power supplies are disconnected. Traditional black start circuits such as Figure 1 As shown in the figure, when the battery is charged and off-grid inverter output is required, the battery charges the bus capacitor by pressing the black start button. After the bus is charged, the auxiliary source is powered to drive the hardware of the whole machine. When the bus reaches the DC contactor pull-in condition, the contactor closes to realize the hardware control of the contactor. However, during the actual black start circuit startup process, due to the influence of manual pressing of the mechanical button and the excessive voltage difference on both sides of the button, the system will experience oscillation problems during the black start process, resulting in excessive input signal of the isolation amplifier to damage the sampling chip.

[0004] Therefore, it is necessary to provide a black start circuit for suppressing oscillation in an energy storage system to solve the problems mentioned in the above background technology. Summary of the invention

[0005] To achieve the above object, the present invention provides the following technical solution: a black start circuit for suppressing oscillation in an energy storage system, comprising: an energy storage battery, a soft start resistor, a first capacitor and an isolation operational amplifier, wherein the soft start resistor, the first capacitor and the isolation operational amplifier are sequentially connected in series between the positive electrode and the negative electrode of the energy storage battery, characterized in that a PMOS tube is connected in series between the energy storage battery and the soft start resistor, a slave control circuit is connected between the PMOS tube and the negative electrode of the energy storage battery, and the slave control circuit is used to control the on and off of the PMOS tube;

[0006] The signal input end of the slave control circuit is connected to the master control circuit via an isolation optocoupler, and the master control circuit is connected to an auxiliary power supply, and the auxiliary power supply is used to supply power to the master control circuit and the isolation optocoupler respectively;

[0007] The master control circuit is used to generate a control signal and transmit the control signal to the slave control circuit through the isolation optocoupler. The slave control circuit controls the PMOS tube to close, and then the energy storage battery charges the first capacitor smoothly to avoid soft start oscillation of the system during the black start process.

[0008] Preferably, the main control circuit comprises: a black start button, a first resistor and a second capacitor, the input end of the black start button is connected to the positive electrode of the auxiliary power supply, the output end of the black start button is connected in series with the first resistor and the second capacitor in sequence, and the second capacitor is grounded;

[0009] The second capacitor is connected in parallel with the primary side of the isolation optocoupler, and the secondary side of the isolation optocoupler is connected to the slave control circuit.

[0010] Preferably, the isolation optical coupler comprises: a light emitting diode and a phototransistor, the light emitting diode is connected in parallel with the second capacitor, the anode of the light emitting diode is connected with the positive electrode of the second capacitor, and the cathode of the light emitting diode is connected with the negative electrode of the second capacitor;

[0011] The emitter of the phototransistor is connected to the positive electrode of the auxiliary power supply, the base of the phototransistor is grounded, and the collector of the phototransistor is connected to the negative electrode of the energy storage battery.

[0012] Preferably, a second resistor is connected in series between the positive electrode of the auxiliary power supply and the emitter of the phototransistor.

[0013] Preferably, the slave control circuit comprises: an NMOS tube and a third capacitor, the third capacitor is connected in parallel with the phototransistor, the positive electrode of the third capacitor is connected between the second resistor and the emitter of the phototransistor, and the negative electrode of the third capacitor is connected to the negative electrode of the energy storage power supply;

[0014] The drain of the NMOS tube is connected to the gate of the PMOS tube, the gate of the NMOS tube is connected between the emitter of the phototransistor and the positive electrode of the third capacitor, and the source of the NMOS tube is connected to the negative electrode of the energy storage battery;

[0015] Wherein, the source of the PMOS tube is connected to the positive electrode of the energy storage power supply, and the drain of the PMOS tube is connected to the input end of the soft-start resistor.

[0016] Preferably, a third resistor is connected in series between the gate of the PMOS tube and the drain of the NMOS tube.

[0017] Preferably, the auxiliary power supply includes a first output end and a second output end, the first output end is connected to the main control circuit and is used to supply the main control circuit with a 24V power supply voltage; the second output end is configured with a step-down chip, and the second output end is used to provide a 5V power supply voltage to the isolation optocoupler.

[0018] Preferably, a third resistor is connected in parallel to the input and output ends of the isolation operational amplifier, and the third resistor is used to collect the current or voltage of the isolation operational amplifier.

[0019] Compared with the prior art, the present invention provides a black start circuit for suppressing oscillation in an energy storage system, which has the following beneficial effects:

[0020] In the present invention, the original mechanical button in the black start circuit is replaced with a PMOS tube, and a main control circuit, an isolation optocoupler and a slave control circuit are provided. A control signal is generated by the main control circuit, and the control signal drives the PMOS tube to be turned on through the isolation optocoupler and the NMOS tube, thereby realizing stable charging of the first capacitor, avoiding the jitter risk caused by manually pressing the mechanical button and the soft start oscillation problem caused by the excessive pressure difference on both sides of the mechanical button, thereby ensuring the normal operation of the sampling chip; and the present invention is suitable for most black start scenarios of energy storage systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of a traditional black start circuit;

[0022] Figure 2 It is a schematic diagram of the overall structure of a black start circuit for suppressing oscillation in an energy storage system;

[0023] In the figure: 1, main control circuit; 2, isolation optocoupler; 3, slave control circuit; 4, soft start resistor; 5, isolation operational amplifier; 6, black start button; C1, first resistor; C2, second resistor; R1, first resistor; R2, second resistor; R3, third resistor; D, light emitting diode; Q, phototransistor. DETAILED DESCRIPTION

[0024] See also Figure 2 The present invention provides a black start circuit for suppressing oscillation in an energy storage system, comprising an energy storage battery, a soft start resistor 4, a first capacitor and an isolation operational amplifier 5, wherein the soft start resistor 4, the first capacitor and the isolation operational amplifier 5 are sequentially connected in series between the positive electrode and the negative electrode of the energy storage battery, and is characterized in that a PMOS tube is connected in series between the energy storage battery and the soft start resistor 4, and a slave control circuit 3 is connected between the PMOS tube and the negative electrode of the energy storage battery, and the slave control circuit 3 is used to control the on and off of the PMOS tube;

[0025] The signal input end of the slave control circuit 3 is connected to the master control circuit 1 through the isolation optical coupler 2, and the master control circuit 1 is connected to an auxiliary power supply, and the auxiliary power supply is used to supply power to the master control circuit 1 and the isolation optical coupler 2 respectively;

[0026] Among them, the main control circuit 1 is used to generate a control signal and transmit the control signal to the slave control circuit 3 through the isolation optocoupler 2. The slave control circuit 3 controls the PMOS tube to close, and then the energy storage battery charges the first capacitor smoothly to avoid system soft start oscillation during the black start process.

[0027] It should be explained that when the external power supply of the energy storage system is completely disconnected and only the energy storage battery has power, when off-grid inverter output is required, the black start control signal is generated by controlling the main control circuit 1, and the control signal passes through the isolation optical coupler 2 to convert the control signal from electrical signal to optical signal to electrical signal, thereby realizing the isolated transmission of electrical signals between different circuits, preventing interference and damage between circuits, and improving the stability and reliability of the system. Afterwards, the PMOS tube is controlled by the slave control circuit 3 to complete the smooth charging of the first capacitor, thereby avoiding the soft start oscillation of the system during the black start process.

[0028] Specifically, the auxiliary power source is a lead-acid battery for fire-fighting equipment in the energy storage system, and the soft-start resistor 4 includes a plurality of current-limiting resistors connected in series.

[0029] Further, the main control circuit 1 includes: a black start button 6, a first resistor and a second capacitor, the input end of the black start button 6 is connected to the positive electrode of the auxiliary power supply, the output end of the black start button 6 is connected in series with the first resistor and the second capacitor in sequence, and the second capacitor is grounded;

[0030] The second capacitor is connected in parallel to the primary side of the isolation optocoupler 2 , and the secondary side of the isolation optocoupler 2 is connected to the slave control circuit 3 .

[0031] Specifically, the isolation optical coupler 2 includes a primary side and a secondary side. The primary side is an input end for receiving an external electrical signal; the secondary side is an output end for receiving an optical signal transmitted from the primary side through optical coupling and converting the optical signal into an electrical signal for output.

[0032] It should be explained that by controlling the black start button 6 to close, a black start control signal is generated, and the control signal is transmitted to the NMOS tube through the isolation optocoupler 2. The NMOS tube controls the PMOS tube to close to charge the first capacitor, thereby eliminating the jitter risk caused by manually pressing the mechanical button and the soft start oscillation problem caused by the excessive pressure difference on both sides of the button when the original black start circuit is started. The isolation optocoupler 2 and the NMOS tube are used to drive the PMOS tube in the energy storage battery circuit to achieve stable charging of the first capacitor by the energy storage battery, thereby ensuring the normal operation of the sampling chip.

[0033] Furthermore, the isolation optical coupler 2 includes: a light emitting diode and a phototransistor, the light emitting diode is connected in parallel with the second capacitor, the anode of the light emitting diode is connected with the positive electrode of the second capacitor, and the cathode of the light emitting diode is connected with the negative electrode of the second capacitor;

[0034] The emitter of the phototransistor is connected to the positive electrode of the auxiliary power supply, the base of the phototransistor is grounded, and the collector of the phototransistor is connected to the negative electrode of the energy storage battery.

[0035] The light emitting diode and the phototransistor are packaged in a tube shell; the primary side of the isolation optical coupler 2 is the light emitting diode, and the secondary side is the phototransistor.

[0036] Specifically, the phototransistor may also be a photodiode or a photosensitive bidirectional thyristor.

[0037] Furthermore, a second resistor is connected in series between the positive electrode of the auxiliary power supply and the emitter of the phototransistor.

[0038] Further, the slave control circuit 3 includes: an NMOS tube and a third capacitor, the third capacitor is connected in parallel with the phototransistor, the positive electrode of the third capacitor is connected between the second resistor and the emitter of the phototransistor, and the negative electrode of the third capacitor is connected to the negative electrode of the energy storage power supply;

[0039] The drain of the NMOS tube is connected to the gate of the PMOS tube, the gate of the NMOS tube is connected between the emitter of the phototransistor and the positive electrode of the third capacitor, and the source of the NMOS tube is connected to the negative electrode of the energy storage battery;

[0040] The source of the PMOS tube is connected to the positive electrode of the energy storage power supply, and the drain of the PMOS tube is connected to the input end of the soft-start resistor 4 .

[0041] It should be explained that when the black start button 6 is pressed, the photosensitive transistor inside the isolation optocoupler 2 is turned on, and the gate of the NMOS tube is at a high level. Then the NMOS tube is turned on and the gate voltage of the PMOS tube is pulled down, so that the PMOS tube is turned on to charge the first capacitor.

[0042] Furthermore, a third resistor is connected in series between the gate of the PMOS tube and the drain of the NMOS tube.

[0043] Furthermore, the auxiliary power supply includes a first output end and a second output end, the first output end is connected to the main control circuit 1, and is used to provide a 24V power supply voltage to the main control circuit 1; the second output end is configured with a step-down chip, and the second output end is used to provide a 5V power supply voltage to the isolation optocoupler 2.

[0044] Furthermore, a third resistor is connected in parallel to the input and output ends of the isolation operational amplifier 5 , and the third resistor is used to collect the current or voltage of the isolation operational amplifier.

[0045] In specific implementation, when the external power supply of the energy storage system is completely disconnected and only the energy storage battery has power, when off-grid inverter output is required, a black start control signal is generated by controlling the main control circuit, and the control signal is converted from an isolated optical coupler to an electrical signal-optical signal-electrical signal and then output, and then the PMOS tube is controlled by the slave control circuit to complete the smooth charging of the first capacitor. The jitter risk caused by manually pressing the mechanical button and the soft start oscillation problem caused by the excessive voltage difference on both sides of the button are eliminated when the original black start circuit is started, and the PMOS tube in the energy storage battery circuit is driven by the isolated optical coupler and the NMOS tube, so that the energy storage battery can charge the first capacitor smoothly, ensuring the normal operation of the sampling chip.

[0046] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A black start circuit for suppressing oscillation in an energy storage system, comprising: An energy storage battery, a soft-start resistor (4), a first capacitor and an isolation operational amplifier (5), wherein the soft-start resistor (4), the first capacitor and the isolation operational amplifier (5) are sequentially connected in series between the positive electrode and the negative electrode of the energy storage battery, and wherein a PMOS tube is connected in series between the energy storage battery and the soft-start resistor (4), and a slave control circuit (3) is connected between the PMOS tube and the negative electrode of the energy storage battery, and the slave control circuit (3) is used to control the on and off of the PMOS tube; The signal input end of the slave control circuit (3) is connected to the master control circuit (1) via an isolation optical coupler (2); the master control circuit (1) is connected to an auxiliary power supply, and the auxiliary power supply is used to supply power to the master control circuit (1) and the isolation optical coupler (2) respectively; The master control circuit (1) is used to generate a control signal and transmit the control signal to the slave control circuit (3) through the isolation optical coupler (2); the slave control circuit (3) controls the PMOS tube to close, and then the energy storage battery charges the first capacitor steadily, thereby avoiding soft start oscillation of the system during the black start process.

2. A black start circuit for suppressing oscillation in an energy storage system according to claim 1, characterized in that: The main control circuit (1) comprises: a black start button (6), a first resistor and a second capacitor, wherein the input end of the black start button (6) is connected to the positive electrode of the auxiliary power supply, the output end of the black start button (6) is connected in series with the first resistor and the second capacitor in sequence, and the second capacitor is grounded; The second capacitor is connected in parallel to the primary side of the isolation optocoupler (2), and the secondary side of the isolation optocoupler (2) is connected to the slave control circuit (3).

3. A black start circuit for suppressing oscillation in an energy storage system according to claim 2, characterized in that: The isolation optical coupler (2) comprises: a light emitting diode and a phototransistor, the light emitting diode is connected in parallel with the second capacitor, the anode of the light emitting diode is connected with the positive electrode of the second capacitor, and the cathode of the light emitting diode is connected with the negative electrode of the second capacitor; The emitter of the phototransistor is connected to the positive electrode of the auxiliary power supply, the base of the phototransistor is grounded, and the collector of the phototransistor is connected to the negative electrode of the energy storage battery.

4. A black start circuit for suppressing oscillation in an energy storage system according to claim 3, characterized in that: A second resistor is connected in series between the positive electrode of the auxiliary power supply and the emitter of the phototransistor.

5. A black start circuit for suppressing oscillation in an energy storage system according to claim 4, characterized in that: The slave control circuit (3) comprises: an NMOS tube and a third capacitor, the third capacitor is connected in parallel with the phototransistor, the positive electrode of the third capacitor is connected between the second resistor and the emitter of the phototransistor, and the negative electrode of the third capacitor is connected to the negative electrode of the energy storage power supply; The drain of the NMOS tube is connected to the gate of the PMOS tube, the gate of the NMOS tube is connected between the emitter of the phototransistor and the positive electrode of the third capacitor, and the source of the NMOS tube is connected to the negative electrode of the energy storage battery; The source of the PMOS tube is connected to the positive electrode of the energy storage power supply, and the drain of the PMOS tube is connected to the input end of the soft-start resistor (4).

6. A black start circuit for suppressing oscillation in an energy storage system according to claim 5, characterized in that: A third resistor is connected in series between the gate of the PMOS tube and the drain of the NMOS tube.

7. A black start circuit for suppressing oscillation in an energy storage system according to claim 2, characterized in that: The auxiliary power supply comprises a first output end and a second output end, the first output end being connected to the main control circuit (1) and being used to supply a 24V power supply voltage to the main control circuit (1); the second output end being provided with a step-down chip and being used to provide a 5V power supply voltage to the isolation optical coupler (2).

8. A black start circuit for suppressing oscillation in an energy storage system according to claim 1, characterized in that: A third resistor is connected in parallel to the input and output ends of the isolation operational amplifier (5), and the third resistor is used to collect the current or voltage of the isolation operational amplifier.

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