Over-charge and over-discharge protection circuit for energy storage high-voltage box

Abstract

The utility model discloses an over-charge and over-discharge protection circuit for an energy storage high-voltage box, which comprises a high-voltage box connected between a PCS power module and an energy storage battery E. The positive electrode of the high-voltage box is connected in series with a charging resistor R and a switch KR which are used for realizing grid-connected soft start of the battery and the PCS power module, and the negative electrode of the high-voltage box is provided with a switch K3. A power direction control branch circuit and a signal generation circuit which are connected in parallel to the charging resistor R and the switch KR are arranged in the high-voltage box, the input end of the signal generation circuit is connected with the output end of the energy storage battery, and the output end of the signal generation circuit is connected with the input end of the power direction control branch circuit. The over-charge and over-discharge protection of the energy storage battery is realized by adopting a hardware circuit, so that the safety and the reliability of the energy storage battery are greatly improved, the transient over-charge and over-discharge caused by pure software protection within the protection judgment time is effectively avoided, and the damage to the battery caused by over-charge and over-discharge under extreme conditions is avoided.

Description

Technical Field

[0001] This utility model relates to the field of energy storage system technology, and more specifically to an overcharge and over-discharge protection circuit for an energy storage high-voltage box. Background Technology

[0002] With the rapid development of the new energy storage industry, the application of energy storage-related products is becoming increasingly widespread. In high-voltage cascaded energy storage systems, a high-voltage box is installed between each battery cluster and the PCS power module. Its main function is to collect and detect in real time the voltage, current, electrical circuit status, ambient temperature, etc. connected to the battery cluster and PCS power module, and operate the opening and closing of each switch as needed to realize grid-connected, off-grid control and protection control of the battery cluster and PCS power module.

[0003] like Figure 1 In a high-voltage cascaded energy storage system, the high-voltage box typically has a switch at both the positive and negative terminals. A resistor series switch branch is connected in parallel with the positive switch to achieve soft-start control on the battery side. Overcharging and over-discharging of the high-voltage box are controlled by software. When the battery cluster is over-voltaged / under-voltaged, the software determines that the direction of the PCS output current is still charging / discharging, and then cuts off the electrical circuit for protection to avoid overcharging / discharging.

[0004] Overcharge and over-discharge protection is an important protection for energy storage batteries. However, using software protection alone does not guarantee safety. Furthermore, software protection itself requires the use of charging and discharging current for judgment. Even under extreme overvoltage or undervoltage conditions, the battery still has to undergo brief charging and discharging cycles. Considering extreme cases, repeated brief charging and discharging cycles under overcharge and over-discharge conditions significantly degrade the safety of battery use. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide an overcharge and over-discharge protection circuit for an energy storage high-voltage box, so as to solve the problems in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.

[0007] An overcharge and over-discharge protection circuit for an energy storage high-voltage box includes a high-voltage box connected between a PCS power module and an energy storage battery E. A charging resistor R and a switch K are connected in series at the positive terminal of the high-voltage box to enable soft-start of the battery and the PCS power module for grid connection. R A switch K3 is installed at the negative terminal of the high-voltage box; a circuit is installed inside the high-voltage box connected in parallel with the charging resistor R and the switch K. R The circuit includes a power direction control branch for overcharge and over-discharge protection and a signal generation circuit for controlling the on / off state of the power direction control branch. The input of the signal generation circuit is connected to the output of the energy storage battery, and the output of the signal generation circuit is connected to the input of the power direction control branch.

[0008] Further optimization technical solutions, the signal generation circuit includes the resistance voltage sampling circuit for sampling the energy storage battery voltage, the overvoltage protection hysteresis comparison circuit and the undervoltage protection hysteresis comparison circuit for comparing the voltage after sampling, and the isolated drive and power amplifier circuit for amplifying the signal after comparison, the input end of the resistance voltage sampling circuit is connected on the energy storage battery, the output end of the resistance voltage sampling circuit is connected respectively the input end of the overvoltage protection hysteresis comparison circuit and the undervoltage protection hysteresis comparison circuit, and the output end of the overvoltage protection hysteresis comparison circuit and the undervoltage protection hysteresis comparison circuit is connected respectively through the isolated drive and power amplifier circuit the input end of the power direction control branch.

[0009] Further optimization technical solutions, the power direction control branch includes the charging control branch for overcharge protection and the discharging control branch for overdischarge protection, the input end of the charging control branch is connected the output end of the isolated drive and power amplifier circuit connected with the overvoltage protection hysteresis comparison circuit, and the input end of the discharging control branch is connected the output end of the isolated drive and power amplifier circuit connected with the undervoltage protection hysteresis comparison circuit.

[0010] Further optimization technical solutions, the charging control branch includes the power switch K1 and the power diode D1 connected in series, and the cathode of the power diode D1 is connected with the positive electrode of the energy storage battery E;The discharging control branch includes the power switch K2 and the power diode D2 connected in series, and the anode of the power diode D2 is connected with the positive electrode of the energy storage battery E.

[0011] Further optimization technical solutions, the power direction control branch can also be provided as two reverse series insulated gate bipolar transistors IGBT1 and IGBT2, the source of IGBT1 and IGBT2 is connected in series, the drain of IGBT1 is connected at one end of the PCS power module, and the drain of IGBT2 is connected at the positive electrode of the energy storage battery E;Diodes are connected in parallel between the drain and the source of IGBT1 and IGBT2, the positive electrode of the diode is connected with the drain, the negative electrode of the diode is connected with the source, and the gate of IGBT1 and IGBT2 is connected with the output end of the signal generation circuit respectively.

[0012] Due to the adoption of the above technical solutions, the technical progress achieved by the utility model is as follows.

[0013] The overcharge and overdischarge protection circuit of the energy storage high-voltage box provided by the utility model realizes overcharge and overdischarge protection of the energy storage battery by using a hardware circuit, greatly improves the safety and reliability of the energy storage battery, effectively avoids the temporary overcharge and overdischarge caused by pure software protection within the protection judgment time, and avoids damage to the battery caused by overcharge and overdischarge under extreme conditions. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a traditional energy storage high voltage box electric circuit structure schematic diagram;

[0015] Figure 2 It is a circuit block diagram of the signal generation circuit of the utility model;

[0016] Figure 3 It is a circuit diagram of the signal generation circuit of the utility model;

[0017] Figure 4 It is a structure schematic diagram of the power direction control branch of the embodiment 1 of the utility model;

[0018] Figure 5 It is a structure schematic diagram of the power direction control branch of the embodiment 2 of the utility model. DETAILED DESCRIPTION

[0019] The utility model will be further explained in detail in connection with the drawings and specific embodiments.

[0020] A kind of overcharge and overdischarge protection circuit of energy storage high voltage box, including high voltage box being connected between PCS power module and energy storage battery E, the positive pole of high voltage box is provided with charging resistance R and switch K R , to realize battery and PCS power module grid-connected soft start, the negative pole of high voltage box is provided with switch K3.

[0021] High voltage box is provided with power direction control branch and signal generation circuit, power direction control branch is connected in parallel in charging resistance R and switch K R , to realize overcharge and overdischarge protection function, signal generation circuit is used to control the on-off of power direction control branch, the input end of signal production circuit is connected the output end of energy storage battery, the output end of signal production circuit is connected the input end of power direction control branch.

[0022] The structure block diagram of signal generation circuit is as Figure 2 Shown, including resistance voltage division sampling circuit, overvoltage protection hysteresis comparison circuit, undervoltage protection hysteresis comparison circuit and isolation drive and power amplifier circuit, resistance voltage division sampling circuit is used to sample energy storage battery voltage, overvoltage protection hysteresis comparison circuit and undervoltage protection hysteresis comparison circuit are used to compare the voltage after sampling, isolation drive and power amplifier circuit are used to amplify the signal after comparison, the input end of resistance voltage division sampling circuit is connected on energy storage battery, the output end of resistance voltage division sampling circuit is connected respectively the input end of overvoltage protection hysteresis comparison circuit and undervoltage protection hysteresis comparison circuit, the output end of overvoltage protection hysteresis comparison circuit and undervoltage protection hysteresis comparison circuit is connected respectively in the input end of power direction control branch through isolation drive and power amplifier circuit, the circuit diagram of signal generation circuit in the utility model is as Figure 3 Shown.

[0023] The power direction control branch includes a charging control branch and a discharging control branch, the charging control branch is used for overcharge protection, and the discharging control branch is used for overdischarge protection; an input end of the charging control branch is connected with an output end of an isolation driving and power amplification circuit connected with the overvoltage protection hysteresis comparison circuit; and an input end of the discharging control branch is connected with an output end of an isolation driving and power amplification circuit connected with the undervoltage protection hysteresis comparison circuit.

[0024] Embodiment 1

[0025] The structure schematic diagram of the power direction control branch of the embodiment is shown in Figure 4 The charging control branch and the discharging control branch are connected in parallel, the charging control branch includes a power switch K1 and a power diode D1 connected in series, and a cathode of the power diode D1 is connected with a positive electrode of the energy storage battery E; the discharging control branch includes a power switch K2 and a power diode D2 connected in series, and an anode of the power diode D2 is connected with the positive electrode of the energy storage battery E.

[0026] The resistance voltage division sampling circuit collects the energy storage battery voltage, and the energy storage battery voltage U I is divided into U S and U S after the resistance voltage division sampling circuit, and U H is input into the overvoltage protection hysteresis comparison circuit and compared with an overvoltage threshold value U S , when U H is greater than U PH , an output signal S Z is output, a hysteresis voltage is set as U S , when U H is less than U Z -U NH , an output signal S PH is output, and S NH / S P1 generates a K1 control signal S N1 / S P1 after the isolation driving and power amplification, S N1 controls K1 to be disconnected, and S S controls K1 to be closed; similarly, U L is input into the undervoltage protection hysteresis comparison circuit and compared with an undervoltage threshold value U S , when U L is less than U PL , an output signal S Z is output, a hysteresis voltage is set as U S , when U L +U Z is greater than U NL , an output signal S PL is output, and S NL / SThe K2 control signal S is generated after isolation driving and power amplification P2 / S N2 , S P2 The K2 is controlled to be open, S N2 The K2 is controlled to be closed.

[0027] When the energy storage battery E voltage is normal, the control signal generation circuit generates S N1 The K1 is controlled to be closed, S N2 The K2 is controlled to be closed, and both power direction control branches are enabled, and the system can normally charge and discharge. When the energy storage battery E voltage is overvoltage, the control signal generation circuit generates S P1 The K1 is controlled to be open, S N2 The K2 is controlled to be closed, and only the discharge control branch is enabled, and the system can discharge and cannot charge. When the energy storage battery E voltage is undervoltage, the control signal generation circuit generates S N1 The K1 is controlled to be closed, S P2 The K2 is controlled to be open, and only the charge control branch is enabled, and the system can charge and cannot discharge.

[0028] Embodiment 2

[0029] The difference between this embodiment and embodiment 1 is that the power direction control branches are different. The structural schematic diagram of the power direction control branch of this embodiment is shown in Figure 5 The power direction control branch is provided as two reverse series insulation gate bipolar transistors IGBT1 and IGBT2. The sources of IGBT1 and IGBT2 are connected in series, the drain of IGBT1 is connected to one end of the PCS power module, and the drain of IGBT2 is connected to the positive electrode of the energy storage battery E. Diodes are connected in parallel between the drain and the source of IGBT1 and IGBT2. The positive electrode of the diode is connected to the drain, and the negative electrode of the diode is connected to the source. The gates of IGBT1 and IGBT2 are connected to the output ends of the signal generation circuit, respectively.

[0030] In the normal working condition, IGBT1 and IGBT2 are both turned on, and the system can charge and discharge. When overvoltage occurs, IGBT1 is turned on and IGBT2 is turned off, and the system can only discharge. When undervoltage occurs, IGBT1 is turned off and IGBT2 is turned on, and the system can only charge.

Claims

1. An overcharge and overdischarge protection circuit for an energy storage high-voltage box, comprising a high-voltage box connected between a PCS power module and an energy storage battery E, a charging resistor R and a switch K being provided in series at the positive electrode of the high-voltage box for realizing soft start of grid connection of the battery and the PCS power module. R A switch K3 is provided at the negative electrode of the high-voltage box. The high-voltage box is provided with a charging resistor R and a switch K R The power direction control branch for realizing overcharge and overdischarge protection function and the signal generating circuit for controlling the on-off of the power direction control branch, the input end of the signal generating circuit is connected with the output end of the energy storage battery, and the output end of the signal generating circuit is connected with the input end of the power direction control branch.

2. The overcharge and overdischarge protection circuit for an energy storage high-voltage box according to claim 1, characterized in that: The signal generating circuit comprises a resistance voltage division sampling circuit for sampling the energy storage battery voltage, overvoltage protection hysteresis comparison circuit and undervoltage protection hysteresis comparison circuit for comparing the sampled voltage, and an isolated driving and power amplification circuit for amplifying the compared signal, the input end of the resistance voltage division sampling circuit is connected to the energy storage battery, the output end of the resistance voltage division sampling circuit is connected to the input end of the overvoltage protection hysteresis comparison circuit and the undervoltage protection hysteresis comparison circuit respectively, and the output end of the overvoltage protection hysteresis comparison circuit and the undervoltage protection hysteresis comparison circuit is connected to the input end of the power direction control branch through the isolated driving and power amplification circuit respectively.

3. The overcharge and overdischarge protection circuit for an energy storage high voltage tank according to claim 1, characterized in that: The power direction control branch comprises a charging control branch for overcharge protection and a discharging control branch for overdischarge protection, the input end of the charging control branch is connected to the output end of the isolated driving and power amplification circuit connected to the overvoltage protection hysteresis comparison circuit, and the input end of the discharging control branch is connected to the output end of the isolated driving and power amplification circuit connected to the undervoltage protection hysteresis comparison circuit.

4. The overcharge and overdischarge protection circuit for an energy storage high voltage tank according to claim 3, characterized in that: The charging control branch comprises a power switch K1 and a power diode D1 connected in series, and the cathode of the power diode D1 is connected to the positive electrode of the energy storage battery E; the discharging control branch comprises a power switch K2 and a power diode D2 connected in series, and the anode of the power diode D2 is connected to the positive electrode of the energy storage battery E.

5. The overcharge and overdischarge protection circuit for an energy storage high voltage tank of claim 1, wherein: The power direction control branch is provided with two reverse series connected insulated gate bipolar transistors IGBT1 and IGBT2, the source of the IGBT1 and the IGBT2 is connected in series, the drain of the IGBT1 is connected to one end of the PCS power module, the drain of the IGBT2 is connected to the positive electrode of the energy storage battery E, a diode is connected in parallel between the drain and the source of the IGBT1 and the IGBT2, the positive electrode of the diode is connected to the drain, the negative electrode of the diode is connected to the source, and the gate of the IGBT1 and the IGBT2 is connected to the output end of the signal generating circuit respectively.

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