Direct-current bus discharge circuit and electronic equipment

Abstract

The utility model relates to a DC bus discharge circuit and an electronic device. The circuit comprises a DC bus input end, an optocoupler isolation unit, an optocoupler power supply unit, an energy storage unit, a discharge unit and a discharge bypass unit. The optocoupler power supply unit is connected with the input end of the direct-current bus to obtain power supply voltage; the optocoupler isolation unit is connected with the optocoupler power supply unit and the direct current bus input end, receives power supply voltage and is conducted; the discharge bypass unit is connected with the optocoupler isolation unit and is switched on when the optocoupler isolation unit is switched on, otherwise, the discharge bypass unit is switched off; the energy storage unit is connected with the optocoupler isolation unit and is charged when the optocoupler isolation unit is conducted; and the discharge unit is connected with the energy storage unit, the discharge bypass unit and the DC bus input end, and is turned off when the discharge bypass unit is turned on, and when the discharge bypass unit is turned off, the energy storage unit is used for discharging to maintain the conduction so as to discharge the DC bus input end. Through the circuit, the residual voltage of the bus can be discharged in time after the DC bus input is powered off, and the safety of the circuit is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic circuit technical field more specifically, relate to a direct current bus discharge circuit and electronic equipment. BACKGROUND

[0002] With the market demand of photovoltaic energy storage product increasing, the demand of energy storage product in market presents explosive growth, and the application of photovoltaic energy storage product in market gradually highlights. The power demand of energy storage product in current market increases from several hundred watts to hundreds of kilowatts, and the power demand of single module gradually increases. With the increase of power of energy storage product, the requirement of technology research and development of energy storage product also gradually increases, and the electrolytic capacitor capacity on the bus increases greatly with the increase of power. The increase of bus capacitor capacity means that the bus stores very large electric shock capacity. When the energy storage converter is powered off and stops working, since the charge stored in the bus capacitor has no release path, a special discharge circuit is needed to release the residual charge of the bus in time, and the bus voltage is discharged to a safe value to prevent electric shock and other hidden dangers. SUMMARY

[0003] The utility model solves the technical problem, and provides a direct current bus discharge circuit and electronic equipment for the demand of direct current bus voltage safety in the prior art.

[0004] The utility model adopts the technical scheme in the solution to the technical problem: a direct current bus discharge circuit is constructed, which comprises: a direct current bus input end, an optocoupler isolation unit, an optocoupler power supply unit, an energy storage unit, a discharge unit and a discharge bypass unit.

[0005] The optocoupler power supply unit is connected to the direct current bus input end and is used to receive the input voltage of the direct current bus input end to obtain a power supply voltage.

[0006] The optocoupler isolation unit is connected to the optocoupler power supply unit and the direct current bus input end and is used to be turned on when the power supply voltage is received.

[0007] The discharge bypass unit is connected to the optocoupler isolation unit and is used to be turned on when the optocoupler isolation unit is turned on and to be turned off when the optocoupler isolation unit is turned off.

[0008] The energy storage unit is connected to the optocoupler isolation unit and is used to be charged when the optocoupler isolation unit is turned on.

[0009] The discharge unit is connected to the energy storage unit, the discharge bypass unit and the direct current bus input end, is used to be turned off when the discharge bypass unit is turned on, and is used to be turned on by discharging the energy storage unit to discharge the direct current bus input end when the discharge bypass unit is turned off.

[0010] Preferably, in the direct current bus discharging circuit one embodiment of the utility model, the optical coupling isolation unit includes first resistance, second resistance and optical coupling chip;

[0011] The first end of the optical coupling chip is connected with the first end of the first resistance and the first end of the second resistance, the second end of the first resistance is connected with the power supply voltage, the second end of the optical coupling chip and the second end of the second resistance are grounded;

[0012] The third end of the optical coupling chip is connected with the positive pole of the direct current bus input end, and the fourth end of the optical coupling chip is connected with the discharge bypass unit and the energy storage unit.

[0013] Preferably, in the direct current bus discharging circuit one embodiment of the utility model, the optical coupling isolation unit further includes a voltage stabilizing circuit;

[0014] The first end of the voltage stabilizing circuit is connected with the positive pole of the direct current bus input end, and the second end of the voltage stabilizing circuit is connected with the negative pole of the direct current bus input end.

[0015] Preferably, in the direct current bus discharging circuit one embodiment of the utility model, the voltage stabilizing circuit includes a voltage stabilizing tube;

[0016] The cathode of the voltage stabilizing tube is connected with the positive pole of the direct current bus input end, and the anode of the voltage stabilizing tube is connected with the negative pole of the direct current bus input end.

[0017] Preferably, in the direct current bus discharging circuit one embodiment of the utility model, the discharge bypass unit includes a first switch tube, a third resistance and a fourth resistance;

[0018] The control end of the first switch tube is connected with the first end of the third resistance and the first end of the fourth resistance, the second end of the third resistance is connected with the fourth end of the optical coupling chip, the first end of the first switch tube is connected with the discharge unit, and the second end of the first switch tube and the second end of the fourth resistance are connected with the negative pole of the direct current bus input end.

[0019] Preferably, in the direct current bus discharging circuit one embodiment of the utility model, the first switch tube is a low-voltage MOS tube.

[0020] Preferably, in the direct current bus discharging circuit one embodiment of the utility model, the energy storage unit includes an isolation diode and a charging capacitor;

[0021] The anode of the isolation diode is connected with the fourth end of the optical coupling chip, the cathode of the isolation diode is connected with the first end of the charging capacitor and the discharge unit, and the second end of the charging capacitor is connected with the negative pole of the direct current bus input end.

[0022] Preferably, in one embodiment of the DC bus discharge circuit of this utility model, the discharge unit includes a discharge resistor, a second switching transistor, a fifth resistor, and a sixth resistor;

[0023] The first end of the bleed resistor is connected to the positive terminal of the DC bus input, and the second end of the bleed resistor is connected to the first end of the second switching transistor.

[0024] The control terminal of the second switch is connected to the first terminal of the fifth resistor and the first terminal of the sixth resistor. The second terminal of the fifth resistor is connected to the energy storage unit. The second terminal of the sixth resistor and the second terminal of the second switch are connected to the negative terminal of the DC bus input.

[0025] Preferably, in one embodiment of the DC bus discharge circuit of this utility model, the second switching transistor is a high-voltage, high-current MOSFET.

[0026] This invention also provides an electronic device, including the DC bus discharge circuit as described above.

[0027] The DC bus discharge circuit and electronic device of this utility model have the following advantages: they can promptly discharge the residual voltage of the bus after the DC bus input is de-energized, thereby improving the safety of the circuit. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0029] Figure 1 This is a logic block diagram of an embodiment of a DC bus discharge circuit according to this utility model;

[0030] Figure 2 This is a circuit diagram of an embodiment of a DC bus discharge circuit according to the present invention. Detailed Implementation

[0031] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0032] like Figure 1 The diagram illustrates an embodiment of a DC bus discharge circuit according to this invention. Figure 1In the shown embodiment of the DC bus discharging circuit, the DC bus discharging circuit comprises: a DC bus input end 110, an optical coupling isolation unit 130, an optical coupling power supply unit 120, an energy storage unit 140, a discharge unit 160 and a discharge bypass unit 150; the optical coupling power supply unit 120 is connected to the DC bus input end 110, and is used to receive an input voltage of the DC bus input end 110 to obtain a power supply voltage; the optical coupling isolation unit 130 is connected to the optical coupling power supply unit 120 and the DC bus input end 110, and is used to be turned on when the power supply voltage is received; the discharge bypass unit 150 is connected to the optical coupling isolation unit 130, and is used to be turned on when the optical coupling isolation unit 130 is turned on, and is turned off when the optical coupling isolation unit 130 is turned off; the energy storage unit 140 is connected to the optical coupling isolation unit 130, and is used to be charged when the optical coupling isolation unit 130 is turned on; the discharge unit 160 is connected to the energy storage unit 140, the discharge bypass unit 150 and the DC bus input end 110, and is used to be turned off when the discharge bypass unit 150 is turned on, and is maintained to be turned on by discharging of the energy storage unit 140 to discharge the DC bus input end 110 when the discharge bypass unit 150 is turned off.

[0033] Specifically, the optocoupler power supply unit 120 is connected to the DC bus input terminal 110 and performs voltage conversion on the input voltage of the DC bus input terminal 100 to obtain the power supply voltage required by the optocoupler isolation unit 130. The optocoupler power supply unit 120 can perform voltage conversion using various voltage conversion circuits. The specific circuit of the optocoupler power supply unit 120 is not limited; any circuit that can achieve this voltage conversion can be selected based on existing circuit conversion circuits. For example, a 5V voltage output is sufficient. When the DC bus input terminal 110 is connected to the circuit and has a voltage output, the optocoupler isolation unit 130 powers on and enters the conducting state. The input voltage of the DC bus input terminal 110 is input to the energy storage unit 140 through the conducting optocoupler isolation unit 130, charging the energy storage unit 140. Simultaneously, the input voltage of the DC bus input terminal 110, after passing through the conducting optocoupler isolation unit 130, drives the discharge bypass unit 150 to conduct. After the discharge bypass unit 150 conducts, it bypasses the discharge unit 160, meaning that the discharge unit 160 does not participate in the operation at this time. Specifically, the discharge unit 160 is set to the off state, and no discharge is performed on the output of the DC bus input terminal 110. This process ensures that the output voltage of the DC bus input terminal 110 is normal, and the downstream equipment operates normally. When the output voltage of the DC bus input terminal 110 is turned off, the optocoupler power supply unit 120 will turn off the power supply voltage because the output voltage of the DC bus input terminal 110 is turned off. The optocoupler isolation unit 130 is powered down and turns off, triggering the discharge bypass unit 150 to turn off. When the bypass unit 150 is turned off, it can no longer control the discharge unit 160. At this time, the discharge unit 160 is powered on through the discharge process of the energy storage unit 140. After the discharge unit 160 is turned on, the residual voltage at the DC bus input terminal 110 can be discharged through the discharge unit 160. By setting the energy storage capacity of the energy storage unit 140, the discharge time of the energy storage unit 140 is made approximately coincident with the discharge time of the DC bus input terminal 110, thereby achieving the discharge of the residual voltage at the DC bus input terminal 110 to a safe value or complete discharge. Considering the operating delay of the optocoupler power supply unit 120, that is, when the DC bus input terminal 110 is initially powered on, the optocoupler power supply unit 120 cannot immediately power on the optocoupler isolation unit 130. The optocoupler isolation unit 130 will receive the power supply voltage and start working after a period of time. Prior to this, the optocoupler isolation unit 130 was always in the off state, the discharge bypass unit 150 was also in the off state, and the energy storage unit 140 was in a state of no energy. The discharge unit 160 did not work, that is, it did not discharge. This process ensures that the circuit is in a stable state at the moment the DC bus input terminal 110 is powered on, and will not cause the discharge unit 160 to malfunction.

[0034] like Figure 2As shown in the figure, in an embodiment, the optocoupler isolation unit 130 comprises a first resistor, a second resistor and an optocoupler chip; the first end of the optocoupler chip is connected to the first end of the first resistor and the first end of the second resistor, the second end of the first resistor is connected to the power supply voltage, and the second end of the optocoupler chip and the second end of the second resistor are grounded; the third end of the optocoupler chip is connected to the positive pole of the DC bus input end 110, and the fourth end of the optocoupler chip is connected to the discharge bypass unit 150 and the energy storage unit 140.

[0035] Specifically, as shown in the figure, Figure 2 As shown in the figure, the first resistor comprises a resistor R1, the second resistor comprises a resistor R2, and the optocoupler chip comprises an optocoupler chip U1. The power supply voltage provided by the optocoupler power supply unit 120 forms a power supply voltage at the first end of the resistor R2 after passing through the resistor R1 and is input to the first end of the optocoupler chip U1. When the first end of the optocoupler chip U1 has the power supply voltage, the light emitting part inside the optocoupler chip U1 is powered on, triggering the light receiving part of the optocoupler chip U1 to work and conduct, the third end of the optocoupler chip U1 is conducted with the fourth end of the optocoupler chip U1, and the positive pole of the DC bus input end 110 is input through the conducted optocoupler chip U1 to form an output at the fourth end of the optocoupler chip U1. The output supplies power to the discharge bypass unit 150 and the energy storage unit 140.

[0036] Optionally, the optocoupler isolation unit 130 further comprises a voltage stabilizing circuit; the first end of the voltage stabilizing circuit is connected to the positive pole of the DC bus input end 110, and the second end of the voltage stabilizing circuit is connected to the negative pole of the DC bus input end 110. Specifically, when the optocoupler isolation unit 130 is conducted, the input voltage of the DC bus input end 110 supplies power to the discharge bypass unit 150 through the voltage stabilizing circuit.

[0037] As shown in the figure, Figure 2 As shown in the figure, in an embodiment, the voltage stabilizing circuit comprises a voltage stabilizing tube ZD1; the cathode of the voltage stabilizing tube ZD1 is connected to the positive pole of the DC bus input end 110, and the anode of the voltage stabilizing tube ZD1 is connected to the negative pole of the DC bus input end 110. That is, the voltage stabilizing tube ZD1 is used for voltage stabilization to ensure that the power supply voltage of the discharge bypass unit 150 is stable.

[0038] Optionally, the discharge bypass unit 150 comprises a first switch tube, a third resistor and a fourth resistor; the control end of the first switch tube is connected to the first end of the third resistor and the first end of the fourth resistor, the second end of the third resistor is connected to the fourth end of the optocoupler chip, the first end of the first switch tube is connected to the discharge unit 160, and the second end of the first switch tube and the second end of the fourth resistor are connected to the negative pole of the DC bus input end 110. As shown in the figure, Figure 2As shown, the first switch tube includes MOS tube Q1, the third resistor includes resistor R3, and the fourth resistor includes resistor R4. The gate of the MOS tube Q1 corresponds to the control end of the first switch tube, and receives the input voltage of the DC bus input end 110 through the resistor R3 to be turned on. When the MOS tube Q1 is turned on, the first end voltage of the MOS tube Q1 is pulled low, that is, the MOS tube Q1 outputs a low level to the bleeding unit 160, and the bleeding unit 160 is in an off state and does not perform voltage bleeding on the DC bus input end 110. In an embodiment, the first switch tube is a low-voltage MOS tube.

[0039] Optionally, the energy storage unit 140 includes an isolation diode and a charging capacitor; the anode of the isolation diode is connected to the fourth end of the optocoupler chip, the cathode of the isolation diode is connected to the first end of the charging capacitor and the bleeding unit 160, and the second end of the charging capacitor is connected to the negative electrode of the DC bus input end 110. Specifically, as shown in Figure 2 As shown, the isolation diode includes diode D1, and the charging capacitor includes charging capacitor C1. When the charging capacitor C1 is discharged, the diode D1 can effectively prevent the discharge voltage of the charging capacitor C1 from entering the fourth pin of the optocoupler chip U1, and then entering the bleeding bypass unit 150, so that the bleeding bypass unit 150 is triggered. Based on this, the charging of the charging capacitor C1 is also provided by the input voltage of the DC bus input end 110, so that in the specific bleeding process, that is, when the device is powered off, the DC bus voltage is used to timely bleed the bus residual voltage, the bleeding requirement of the bus is met, the reliability of the bleeding circuit is high, the cost of the bleeding circuit is extremely low, the space of the entire device such as the energy storage system is not occupied, and the circuit performance is improved.

[0040] Optionally, the bleeding unit 160 includes a bleeding resistor, a second switch tube, a fifth resistor, and a sixth resistor; the first end of the bleeding resistor is connected to the positive electrode of the DC bus input end 110, and the second end of the bleeding resistor is connected to the first end of the second switch tube; the control end of the second switch tube is connected to the first end of the fifth resistor and the first end of the sixth resistor, the second end of the fifth resistor is connected to the energy storage unit 140, and the second end of the sixth resistor and the second end of the second switch tube are connected to the negative electrode of the DC bus input end 110. Specifically, as shown in Figure 2As shown, the bleed-off resistor comprises resistor R8, the second switch tube comprises MOS tube Q2, the fifth resistor comprises resistor R5, and the sixth resistor comprises resistor R6. The gate of the MOS tube Q2 corresponds to the control end of the second switch tube, and is turned on or turned off according to the voltage at the first end of the resistor R6. When the bleed-off bypass unit 150 is turned on, the voltage at the second end of the resistor R6 is pulled low, and the MOS tube Q2 is turned off. When the bleed-off bypass unit 150 is turned off, if the energy storage unit 140 is discharged, the voltage at the second end of the resistor R6 is pulled high, and the MOS tube Q2 is turned on. At this time, the residual voltage of the DC bus input end 110 can be discharged to the negative pole of the DC bus input end 110 through the resistor R8 and the turned-on MOS tube Q2. In a specific embodiment, the second switch tube can be a high-voltage and high-current MOS tube.

[0041] The circuit according to the present application can realize the isolated control of the control circuit and the bleed-off circuit by using the isolation optical coupling and the bleeder tube to form a corresponding control circuit of the bleed-off circuit, and can drive the bleed-off circuit to work by using the bus voltage to discharge the residual voltage of the bus.

[0042] In addition, the electronic device according to the present application comprises the above DC bus discharge circuit. The electronic device can be an electronic device powered by a DC bus, such as an energy storage inverter system. The electronic device can realize the discharge process of the residual voltage when the DC bus is powered off by the DC bus discharge circuit, thereby ensuring the safety of the electronic device.

[0043] It can be understood that the above embodiments only express the preferred embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the present application. It should be pointed out that for ordinary skilled persons in the art, the above technical features can be freely combined without departing from the concept of the present application, and some modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, any equivalent transformation and modification within the scope of the claims of the present application should belong to the scope of the claims of the present application.

Claims

1. A DC bus discharge circuit, characterized in that, include: DC bus input terminal, optocoupler isolation unit, optocoupler power supply unit, energy storage unit, discharge unit and discharge bypass unit; The optocoupler power supply unit is connected to the DC bus input terminal and is used to receive the input voltage of the DC bus input terminal to obtain the power supply voltage; The optocoupler isolation unit connects the optocoupler power supply unit and the DC bus input terminal, and is used to turn on when the power supply voltage is received; The discharge bypass unit is connected to the optocoupler isolation unit and is used to turn on when the optocoupler isolation unit is turned on and turn off when the optocoupler isolation unit is turned off. The energy storage unit is connected to the optocoupler isolation unit and is used to charge the optocoupler isolation unit when it is turned on. The discharge unit is connected to the energy storage unit, the discharge bypass unit and the DC bus input terminal. It is used to turn off when the discharge bypass unit is turned on, and to maintain conduction through the discharge of the energy storage unit to discharge the DC bus input terminal when the discharge bypass unit is turned off.

2. The DC bus discharge circuit according to claim 1, characterized in that, The optocoupler isolation unit includes a first resistor, a second resistor, and an optocoupler chip; The first end of the optocoupler chip is connected to the first end of the first resistor and the first end of the second resistor, the second end of the first resistor is connected to the power supply voltage, and the second end of the optocoupler chip and the second end of the second resistor are grounded. The third terminal of the optocoupler chip is connected to the positive terminal of the DC bus input, and the fourth terminal of the optocoupler chip is connected to the discharge bypass unit and the energy storage unit.

3. The DC bus discharge circuit according to claim 2, characterized in that, The optocoupler isolation unit also includes a voltage regulator circuit; The first terminal of the voltage regulator circuit is connected to the positive terminal of the DC bus input, and the second terminal of the voltage regulator circuit is connected to the negative terminal of the DC bus input.

4. The DC bus discharge circuit according to claim 3, characterized in that, The voltage regulator circuit includes a Zener diode; The cathode of the Zener diode is connected to the positive terminal of the DC bus input, and the anode of the Zener diode is connected to the negative terminal of the DC bus input.

5. The DC bus discharge circuit according to claim 2, characterized in that, The discharge bypass unit includes a first switching transistor, a third resistor, and a fourth resistor; The control terminal of the first switch is connected to the first terminal of the third resistor and the first terminal of the fourth resistor. The second terminal of the third resistor is connected to the fourth terminal of the optocoupler chip. The first terminal of the first switch is connected to the discharge unit. The second terminal of the first switch and the second terminal of the fourth resistor are connected to the negative terminal of the DC bus input.

6. The DC bus discharge circuit according to claim 5, characterized in that, The first switching transistor is a low-voltage MOSFET.

7. The DC bus discharge circuit according to claim 2, characterized in that, The energy storage unit includes an isolation diode and a charging capacitor; The anode of the isolation diode is connected to the fourth terminal of the optocoupler chip, the cathode of the isolation diode is connected to the first terminal of the charging capacitor and the discharge unit, and the second terminal of the charging capacitor is connected to the negative terminal of the DC bus input.

8. The DC bus discharge circuit according to claim 1, characterized in that, The discharge unit includes a discharge resistor, a second switching transistor, a fifth resistor, and a sixth resistor; The first end of the bleed resistor is connected to the positive terminal of the DC bus input, and the second end of the bleed resistor is connected to the first end of the second switching transistor. The control terminal of the second switch is connected to the first terminal of the fifth resistor and the first terminal of the sixth resistor. The second terminal of the fifth resistor is connected to the energy storage unit. The second terminal of the sixth resistor and the second terminal of the second switch are connected to the negative terminal of the DC bus input.

9. The DC bus discharge circuit according to claim 8, characterized in that, The second switching transistor is a high-voltage, high-current MOSFET.

10. An electronic device, characterized in that, Includes the DC bus discharge circuit as described in any one of claims 1 to 9.

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