An intelligent capacitor pulse discharge device

Abstract

The present invention relates to the technical field of DC fast circuit breakers, and specifically to an intelligent capacitor pulse discharge device, comprising a charging unit, a sampling unit, a capacitor, a control unit, and a trigger switch for controlling the discharge of the capacitor; the charging unit, the sampling unit, and the capacitor are connected in parallel in sequence, and the charging unit is connected to an external power supply for converting the output of the external power supply into direct current, and outputting it to the capacitor for charging; the sampling unit detects the voltage value output by the charging unit to the capacitor and the charge amount of the capacitor, and feeds back the detection result to the control unit; the control unit is used to receive an external trigger signal input from the outside, and according to the external trigger signal, controls the conduction and disconnection of the trigger switch, so that the capacitor is turned on and discharged when the trigger switch is turned on. The device does not need to be additionally configured with a capacitor charging device, can realize the forward pulse discharge and reverse pulse discharge of the capacitor, and has the function of detecting the connection status of the external load.

Description

Technical Field

[0001] The invention relates to the technical field of direct current fast circuit breakers, and in particular to an intelligent capacitor pulse discharge device. Background Art

[0002] DC fast circuit breakers are key equipment for the safe operation and protection of DC power grids, and their performance is critical to the formulation of system protection strategies and engineering implementation. In recent years, with the continuous development of technology, hybrid DC vacuum circuit breakers based on the principle of forced commutation have been widely used in long-distance DC high-voltage transmission systems, distributed DC power grids, and rail transit traction power supply systems due to their advantages of strong current-carrying capacity and high breaking capacity. The hybrid DC vacuum circuit breaker consists of a normal current-carrying branch and a forced commutation shutoff branch composed of a capacitor pulse discharge device. Among them, the capacitor pulse discharge device directly determines whether the hybrid DC vacuum circuit breaker is successfully opened or closed, and is a key component of the DC vacuum circuit breaker.

[0003] Most of the capacitor pulse discharge devices in the prior art have the disadvantages of complex structure, large size, low reliability, need for additional charging devices, and inability to achieve forward pulse discharge and reverse pulse discharge.

[0004] For example, a supercapacitor discharge device disclosed in the patent with application announcement number CN112865275A includes a main control unit for controlling supercapacitor discharge, a voltage detection unit for detecting supercapacitor voltage, a current detection unit for detecting supercapacitor discharge current, an inverter unit for controlling the on / off of the supercapacitor discharge circuit and the selection of the discharge circuit, and a motor unit for supercapacitor energy discharge. The supercapacitor discharge device needs to be additionally configured with a capacitor charging device, and cannot realize the disadvantages of forward pulse discharge and reverse pulse discharge of the capacitor.

[0005] For another example, the patent with application announcement number CN113037068A discloses a capacitor discharge circuit and a power conversion circuit, including a main discharge circuit and a residual voltage discharge circuit, the main discharge circuit and the residual voltage discharge circuit are respectively connected between the positive electrode of the bus capacitor and the negative electrode of the bus capacitor, and the main discharge circuit is connected to the residual voltage discharge circuit. When the main discharge circuit does not receive a shutdown signal and the capacitor voltage is less than the voltage threshold, the residual voltage discharge circuit is controlled to be in a conducting state to discharge the voltage of the bus capacitor. The capacitor discharge circuit also requires an additional capacitor charging device, and also has the disadvantage of being unable to realize the forward pulse discharge and reverse pulse discharge of the capacitor. In addition, the capacitor discharge circuit cannot detect the connection status of the external load.

[0006] Therefore, it is necessary to provide a capacitor pulse discharge device that does not require an additional capacitor charging device, can realize forward pulse discharge and reverse pulse discharge of the capacitor, and has the function of detecting the connection status of an external load. Summary of the invention

[0007] Technical issues solved

[0008] In view of the above-mentioned shortcomings of the prior art, the present invention provides an intelligent capacitor pulse discharge device, which does not require additional capacitor charging device, can realize forward pulse discharge and reverse pulse discharge of the capacitor, and has the function of detecting the connection status of the external load.

[0009] Technical Solution

[0010] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0011] The present invention provides an intelligent capacitor pulse discharge device, comprising a charging unit, a sampling unit, a capacitor, a control unit and a trigger switch for controlling the discharge of the capacitor;

[0012] The charging unit, the sampling unit and the capacitor are connected in parallel in sequence. The charging unit is connected to an external power supply to convert the output of the external power supply into direct current, and output it to the capacitor for charging; the sampling unit detects the voltage value output by the charging unit to the capacitor and the charge amount of the capacitor, and feeds back the detection result to the control unit; the control unit is used to receive an external trigger signal input from the outside, and control the conduction and cutoff of the trigger switch according to the external trigger signal, so that the capacitor is turned on and discharged when the trigger switch is turned on.

[0013] Furthermore, the external trigger signal includes a forward trigger signal and a reverse trigger signal, and the control unit controls the trigger switch through the trigger unit. When the control unit receives the forward trigger signal, the trigger unit controls the trigger switch to be turned on in a first manner to discharge the capacitor in a forward pulse. When the control unit receives the reverse trigger signal, the trigger unit controls the trigger switch to be turned on in a second manner to discharge the capacitor in a reverse pulse.

[0014] Further, the trigger switch includes a first trigger switch, a second trigger switch, a third trigger switch and a fourth trigger switch; the first mode of conduction is that the first trigger switch and the fourth trigger switch are turned on, and the second trigger switch and the third trigger switch are turned off; the second mode of conduction is that the second trigger switch and the third trigger switch are turned on, and the first trigger switch and the fourth trigger switch are turned off.

[0015] Furthermore, it also includes a detection unit and a readiness judgment element, the detection unit is used to detect whether the load connected to the capacitor is connected and whether it is normal, if the load is connected and normal, then output a load connected signal; the readiness judgment element is used to send a readiness signal to the outside when receiving the load connected signal and the charging completion signal at the same time, and the charging completion signal is sent by the control unit to the readiness judgment element.

[0016] Furthermore, it also includes a residual pressure discharge circuit, which is used to release the energy stored in the capacitor when the intelligent capacitor pulse discharge device fails or stops working.

[0017] Furthermore, the residual pressure discharge circuit includes a residual pressure discharge resistor and a residual pressure discharge switch connected in series, and the control unit is used to control the conduction and disconnection of the residual pressure discharge switch. If it is turned on, the capacitor discharges to the residual pressure discharge resistor; if it is turned off, the capacitor does not discharge to the residual pressure discharge resistor.

[0018] Furthermore, the residual pressure relief switch is a normally closed contactor.

[0019] Furthermore, the control unit is also provided with a voltage regulating element, and the control unit determines the output voltage value of the charging unit according to the regulating value set on the voltage regulating element; the capacitor is also connected in parallel with a freewheeling element, and the freewheeling element is used to prevent overvoltage from occurring during the discharge process of the capacitor.

[0020] Furthermore, the freewheeling element is a freewheeling diode or a varistor.

[0021] Furthermore, the trigger switch is a thyristor element or an IGBT / IGCT element.

[0022] Beneficial Effects

[0023] The technical solution provided by the present invention has the following beneficial effects compared with the known public technology: it provides an intelligent capacitor pulse discharge device, which integrates a capacitor, a charging unit, a sampling unit, a residual pressure discharge circuit and an external load detection unit, and can intelligently detect the capacitor voltage and the external load connection status. It has the advantages of compact size, safety and reliability, and the device can realize the characteristics of forward pulse discharge and reverse pulse discharge of the capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic diagram of an intelligent capacitor pulse discharge device provided in Embodiment 1 of the present invention;

[0026] Figure 2 A schematic diagram of another intelligent capacitor pulse discharge device provided in the first embodiment of the present invention;

[0027] Figure 3 A schematic diagram of an intelligent capacitor pulse discharge device provided in Embodiment 2 of the present invention;

[0028] Figure 4 A schematic diagram of another intelligent capacitor pulse discharge device provided in the second embodiment of the present invention;

[0029] The reference numerals are described as follows:

[0030] 1-power input terminal, 2-charging unit, 3-sampling unit, 4-residual pressure discharge resistor, 5-residual pressure discharge switch, 6-trigger switch, 61-first trigger switch, 62-second trigger switch, 63-third trigger switch, 64-fourth trigger switch, 10-capacitor, 11-detection unit, 12-freewheeling element, 13-power output terminal, 14-ready signal, 15-charging voltage signal, 16-ready judgment element, 17-trigger unit, 18-control unit, 19-voltage adjustment element, 20-external trigger signal, 21-forward trigger signal, 22-reverse trigger signal. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Embodiment 1

[0033] See also Figure 1 and Figure 2The present invention provides an intelligent capacitor pulse discharge device, comprising a charging unit 2, a sampling unit 3, a capacitor 10, a control unit 18 and a trigger switch 6 for controlling the discharge of the capacitor 10; the charging unit 2, the sampling unit 3 and the capacitor 10 are connected in parallel in sequence, the charging unit 2 is connected to an external power supply, and is used to convert the output of the external power supply into direct current, and output it to the capacitor 10 for charging; the sampling unit 3 detects the voltage value output by the charging unit 2 to the capacitor 10 and the charge amount of the capacitor 10, and feeds back the detection result to the control unit 18; the control unit 10 can judge the charging status of the capacitor 10 according to the voltage value and the charge amount, and can output the judgment result, the operator can decide whether to input an external trigger signal to the control unit 18 according to the judgment result, the control unit 18 receives the external trigger signal input from the outside, and controls the conduction and disconnection of the trigger switch 6 according to the external trigger signal, so that when the trigger switch 6 is turned on, the capacitor 10 is connected to discharge, and the capacitor 10 can be connected to a load and discharge to the connected load.

[0034] In this embodiment, the intelligent capacitor pulse discharge device also includes a residual pressure discharge circuit, which is connected in parallel at both ends of the capacitor 10. When the intelligent capacitor pulse discharge device fails or does not work, the energy stored in the capacitor 10 can be released to ensure safety. Figure 1 and Figure 2 The residual pressure discharge circuit generally includes a residual pressure discharge resistor 4 and a residual pressure discharge switch 5 connected in series. The control unit 18 is used to control the conduction and disconnection of the residual pressure discharge switch 5. If it is turned on, the capacitor 10 discharges to the residual pressure discharge resistor 4. If it is turned off, the capacitor 10 does not discharge to the residual pressure discharge resistor 4.

[0035] In this embodiment, the capacitor 10 can be discharged by turning on the trigger switch 6. The discharge output side of the capacitor 10 is also provided with a detection unit 11, which can detect whether the external load on the power output terminal 13 is connected and whether the load is normal. The two output terminals of the power output terminal 13 are connected in parallel with a freewheeling element 12 to prevent overvoltage from occurring during the capacitor discharge process. The control unit 18 can receive an external trigger signal 20, and control the on and off of the trigger switch 6 through the trigger unit 17 according to the external trigger signal 20. The control unit 18 is provided with a voltage regulating element 19, which can change the output voltage value of the charging unit 2 according to the adjustment value, measure the output voltage value of the charging unit 2 through the sampling unit 3, and output a charging voltage signal 15 to the outside, which reflects the output voltage value, that is, the charging voltage of the capacitor 10. After the capacitor 10 is fully charged, the control unit 18 can output a charging completion signal, which is connected in parallel with the load connection signal output by the detection unit 11, and send a ready signal 14 to the outside through the ready judgment element 16. That is, the readiness determination element 16 receives the charging completion signal and the load connection signal at the same time, and sends a readiness signal 14 to the outside.

[0036] During specific implementation, both the charging process and the discharging process are controlled by the control unit 18 .

[0037] The charging process is as follows:

[0038] like Figure 1 As shown, when the intelligent capacitor pulse discharge device starts working, the control unit 18 controls the residual pressure discharge circuit to be turned off and not put into operation, and the capacitor 10 can be charged normally. The control unit 18 controls the charging unit 2 to charge the capacitor 10, and measures the voltage value across the capacitor 10 through the sampling unit 3 to determine whether the capacitor 10 is fully charged. When the capacitor 10 is fully charged, the control unit 18 controls the charging unit 2 to stop charging and wait for the pulse discharge instruction.

[0039] The discharge process is as follows:

[0040] like Figure 1 As shown, when the control unit 18 receives the pulse discharge instruction from the external trigger signal 20, it sends an action signal to the trigger unit 17, and the trigger unit 17 controls the trigger switch 6 to turn on, and the capacitor 10 starts to discharge. After the capacitor 10 is discharged, the trigger switch 6 is turned off, and the freewheeling element 12 will form a freewheeling loop with the external load to protect the circuit components from being damaged.

[0041] In addition, the control unit 18 is also used for fault detection:

[0042] like Figure 1 As shown, when the control unit 18 detects an internal fault, the control unit 18 controls the residual pressure discharge circuit to release the energy stored in the capacitor 10 and discharge the residual pressure of the capacitor to ensure safety.

[0043] The intelligent capacitor pulse discharge device integrates a capacitor, a charging unit, a sampling unit, a residual pressure discharge circuit and an external load detection unit. It can intelligently detect the capacitor voltage and the external load connection status and has the advantages of compact size, safety and reliability.

[0044] In this embodiment, the residual pressure discharge circuit generally includes a residual pressure discharge resistor 4 and a residual pressure discharge switch 5 connected in series. The control unit 18 is used to control the conduction and disconnection of the residual pressure discharge switch 5. If it is turned on, the capacitor 10 discharges to the residual pressure discharge resistor 4. If it is turned off, the capacitor 10 does not discharge to the residual pressure discharge resistor 4.

[0045] In this embodiment, when the control unit 18 fails or the external power supply of the capacitor pulse discharge device fails, the residual pressure discharge switch 5 can be set as a normally closed contactor to ensure the safety of the device. Figure 1 and Figure 2When the control unit 18 fails or the external power supply of the capacitor pulse discharge device loses power, since the residual pressure discharge switch 5 is a normally closed switch, the residual pressure discharge circuit composed of the residual pressure discharge switch 5 and the residual pressure discharge resistor 4 automatically releases the energy stored in the capacitor 10, discharges the residual pressure of the capacitor, and ensures the safety of the device.

[0046] In this embodiment, see Figure 2 The freewheeling element 12 can be a freewheeling diode, which is sometimes also called a flywheel diode. It is a diode used in conjunction with an inductive load. When the current of the inductive load suddenly changes or decreases, a sudden voltage will be generated at the two ends of the inductor, which may damage other components. When used with a freewheeling diode, its current can change more smoothly to avoid the occurrence of surge voltage. It is a commonly used component for preventing overvoltage.

[0047] Embodiment 2

[0048] See also Figure 3 and Figure 4 This embodiment provides an intelligent capacitor pulse discharge device. Different from the above, the external trigger signal 20 input by the control unit 18 includes a forward trigger signal 21 and a reverse trigger signal 22. If the control unit 18 receives the forward trigger signal 21, the capacitor 10 performs forward pulse discharge. If the control unit 18 receives the reverse trigger signal 22, the capacitor 10 performs reverse pulse discharge. By distinguishing the external trigger signal 20 into the forward trigger signal 21 and the reverse trigger signal 22, different discharge requirements of the capacitor 10 are achieved, and the characteristics of the device that can perform forward pulse discharge and reverse pulse discharge of the capacitor are achieved.

[0049] In this embodiment, in order to distinguish between the forward pulse discharge and the reverse pulse discharge of the capacitor 10, it is generally achieved by setting the trigger switch 6, see Figure 3 For example, the trigger switch 6 can be set to include a first trigger switch 61, a second trigger switch 62, a third trigger switch 63 and a fourth trigger switch 64; if the first trigger switch 61 and the fourth trigger switch 64 are turned on, the second trigger switch 62 and the third trigger switch 63 are turned off, and the capacitor 10 is discharged in a forward pulse; if the second trigger switch 62 and the third trigger switch 63 are turned on, the first trigger switch 61 and the fourth trigger switch 64 are turned off, and the capacitor 10 is discharged in a reverse pulse.

[0050] In this embodiment, the trigger switch 6 is a thyristor element or an IGBT / IGCT element. Thyristor elements have the advantages of small size, high efficiency, and long life. In the automatic control system, it can be used as a high-power driver to control high-power equipment with a low-power control. It has been widely used in AC and DC motor speed control systems, power regulation systems, and follow-up systems. IGCT elements have the characteristics of large current, high blocking voltage, high switching frequency, high reliability, compact structure, and low conduction loss. IGBT combines the advantages of GTR and MOSFET devices, and has the characteristics of small driving power, low saturation voltage drop, and large current density.

[0051] In this embodiment, the charging unit 2 charges the capacitor 10 in a constant voltage manner or a constant current manner, thereby ensuring the stability of charging and the stability of obtaining a charging signal.

[0052] In this embodiment, the charging unit 2 generally has an isolation function to isolate the charging power source from the discharging circuit to avoid interference between the two.

[0053] In this embodiment, see Figure 4 The freewheeling element 12 is a varistor, which is a resistor device with nonlinear volt-ampere characteristics. It is mainly used to clamp the voltage when the circuit is subjected to overvoltage, and absorb excess current to protect sensitive devices. It has impact resistance characteristics, that is, the varistor itself should be able to withstand the specified impact current, impact energy, and the average power when multiple impacts occur in succession; and life characteristics, one is the continuous working voltage life, that is, the varistor should be able to work reliably for a specified time under the specified ambient temperature and system voltage conditions, and the other is the impact life, that is, the number of times it can reliably withstand the specified impact.

[0054] The advantage of the present invention is that it provides an intelligent capacitor pulse discharge device, which integrates a capacitor, a charging unit, a sampling unit, a residual pressure discharge circuit and an external load detection unit. It can intelligently detect the capacitor voltage and the external load connection status, has the advantages of compact size, safety and reliability, and the device can realize the characteristics of forward pulse discharge and reverse pulse discharge of the capacitor.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. An intelligent capacitor pulse discharge device, characterized in that: It comprises a charging unit, a sampling unit, a capacitor, a control unit and a trigger switch for controlling the discharge of the capacitor; the charging unit, the sampling unit and the capacitor are connected in parallel in sequence, the charging unit is connected to an external power supply, and is used to convert the output of the external power supply into direct current, and output it to the capacitor for charging; the sampling unit detects the voltage value output by the charging unit to the capacitor and the charge amount of the capacitor, and feeds back the detection result to the control unit; The control unit is used to receive an external trigger signal input from the outside, and according to the external trigger signal, control the on and off of the trigger switch, so that the capacitor is turned on and discharged when the trigger switch is turned on; the external trigger signal includes a forward trigger signal and a reverse trigger signal, and the control unit controls the trigger switch through the trigger unit. When the control unit receives the forward trigger signal, the trigger unit controls the trigger switch to be turned on in a first manner to discharge the capacitor in a forward pulse, and when the control unit receives the reverse trigger signal, the trigger unit controls the trigger switch to be turned on in a second manner to discharge the capacitor in a reverse pulse; the trigger switch includes a first trigger switch, a second trigger switch, a third trigger switch and a fourth trigger switch; the first mode of conduction is that the first trigger switch and the fourth trigger switch are turned on, and the second trigger switch and the third trigger switch are turned off; the second mode of conduction is that the second trigger switch and the third trigger switch are turned on, and the first trigger switch and the fourth trigger switch are turned off, and the capacitor is discharged in a reverse pulse; It also includes a detection unit and a readiness judgment element, wherein the detection unit is used to detect whether the load connected to the capacitor is connected and whether it is normal, and if the load is connected and normal, output a load connected signal; the readiness judgment element is used to send a readiness signal to the outside when receiving the load connected signal and the charging completion signal at the same time, and the charging completion signal is sent by the control unit to the readiness judgment element; It also includes a residual pressure discharge circuit, which is used to release the energy stored in the capacitor when the intelligent capacitor pulse discharge device fails or stops working; the residual pressure discharge circuit includes a residual pressure discharge resistor and a residual pressure discharge switch connected in series, and the control unit is used to control the conduction and disconnection of the residual pressure discharge switch. If it is turned on, the capacitor discharges to the residual pressure discharge resistor, and if it is turned off, the capacitor does not discharge to the residual pressure discharge resistor; the control unit is also provided with a voltage regulating element, and the control unit determines the output voltage value of the charging unit according to the regulating value set on the voltage regulating element; the capacitor is also connected in parallel with a freewheeling element, and the freewheeling element is used to prevent overvoltage from occurring during the discharge process of the capacitor.

2. The intelligent capacitor pulse discharge device according to claim 1 is characterized in that: The residual pressure relief switch is a normally closed contactor.

3. The intelligent capacitor pulse discharge device according to claim 1 is characterized in that: The freewheeling element is a freewheeling diode or a varistor.

4. The intelligent capacitor pulse discharge device according to any one of claims 1 to 3, characterized in that: The trigger switch is a thyristor element or an IGBT / IGCT element.

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