Intelligent charge and discharge device for electrolytic capacitor

Abstract

The utility model discloses a kind of intelligent charge-discharge equipment for electrolytic capacitor, it is related to the technical field of electrolytic capacitor charge-discharge device, the utility model includes autotransformer T1, its input end is connected with alternating current power supply, its output end is connected with alternating voltage table PV1 in parallel, for real-time monitoring the output voltage of autotransformer T1 after adjustment;Hierarchical control execution circuit, including transformer T2, its output end has multiple groups of different turns ratio tap, respectively connected to the control end of one contact KM1, two contact KM2 and three contact KM3, three contactors are connected with different voltage grade alternating current power supply to charging circuit as required under the instruction of control loop.The application is realized by adopting PLC control, multiple protection measures, intelligent monitoring and box type design, the intelligent charge-discharge of electrolytic capacitor, with high degree of automation, various functions, safe and reliable, easy to operate and other significant technical effects.

Description

Technical Field

[0001] This utility model relates to the technical field of electrolytic capacitor charging and discharging devices, specifically an intelligent charging and discharging device for electrolytic capacitors. Background Technology

[0002] Electrolytic capacitors, as core components of power electronic devices, face a serious risk of performance degradation after long-term storage: electrolyte ion precipitation leads to decreased conductivity, dielectric aging causes insulation deterioration, and applying rated voltage directly can cause a surge in leakage current, overheating and bulging, or even explosion. Traditional charging solutions have fundamental flaws: The voltage regulating transformer solution relies on a three-phase power supply and requires manual voltage regulation throughout the process. This results in discontinuous voltage control, lack of overcharge protection, and a high operational error rate. While the multi-stage DC power module solution reduces the difficulty of voltage regulation, it requires multiple power supplies (often 3-4 sets of different voltage modules), increasing the equipment size by more than 60%, and frequent plugging and unplugging of wiring can easily lead to polarity errors. Common defects mainly manifest in the lack of a real-time monitoring mechanism, making it impossible to detect abnormal capacitor temperature or voltage in a timely manner; the lack of adaptive adjustment capability, making it difficult to adapt to the needs of different capacitor specifications, such as the difference between bus capacitors and individual capacitors; in addition, the operation process is complex and maintenance efficiency is low. These factors collectively affect the stability and reliability of the system.

[0003] The aforementioned problems particularly hinder the rapid maintenance of critical equipment such as frequency converters. There is an urgent need to develop solutions integrating intelligent control, multi-mode charging, and lightweight design to overcome the triple technical bottlenecks of operational safety, equipment portability, and the level of automation in electrolytic capacitor charging equipment. Utility Model Content

[0004] To address the aforementioned problems, namely the issues raised in the background art, this utility model proposes an intelligent charging and discharging device for electrolytic capacitors, comprising a main circuit and a control circuit, wherein the main circuit includes: The voltage regulating circuit includes a main circuit power switch QF1 and an autotransformer T1. The input terminal of the autotransformer T1 is connected to an AC power supply, and its output terminal is connected in parallel with an AC voltmeter PV1 for real-time monitoring of the output voltage after adjustment by the autotransformer T1. The graded control execution circuit includes a transformer T2. The output terminal of the transformer T2 has multiple taps with different turns ratios, which are respectively connected to the control terminals of the first-gear contactor KM1, the second-gear contactor KM2, and the third-gear contactor KM3. Under the command of the control circuit, the first-gear contactor KM1, the second-gear contactor KM2, and the third-gear contactor KM3 connect AC power supplies of different voltage levels to the charging circuit as needed. The rectifier circuit includes a rectifier module D1 that converts regulated alternating current into direct current. An electrolytic capacitor charging circuit, the output of which can be optionally connected to a DC bus electrolytic capacitor or a single electrolytic capacitor; wherein the single electrolytic capacitor charging circuit is connected in series with a pre-charging resistor R1 to control the initial current, and also includes a DC voltmeter PV2 and a voltage switching relay KA for switching the monitoring signal source of the DC voltmeter PV2. The electrolytic capacitor discharge circuit includes a discharge contactor KM4 and a discharge resistor R2.

[0005] The present invention is further configured such that: the control circuit includes a PLC, the digital input module of the PLC is connected to an emergency stop button SBO and a temperature control switch; the digital output module of the PLC is connected to a voltage switching relay KA, a first-gear contactor KM1, a second-gear contactor KM2, a third-gear contactor KM3, a discharge contactor KM4 and a cooling fan FJ.

[0006] A further feature of this invention is that the rectifier module D1, the first-speed contactor KM1, the second-speed contactor KM2, and the third-speed contactor KM3 are all connected in series with fuses FU to achieve overcurrent protection.

[0007] A further feature of this invention is that the charging and discharging device is a housing, and a touch screen is provided on the outer surface of the housing. The touch screen is connected to the PLC inside the housing via an RS485 interface. The housing is also equipped with an autotransformer T1 adjustment knob, a pre-charge resistor R1 adjustment knob, an AC voltmeter PV1, a DC voltmeter PV2, and an emergency stop button SBO.

[0008] A further feature of this invention is that the enclosure is also provided with a main circuit power switch QF1, a control circuit power switch QF2, a main circuit power input port L / N, a DC output port, and a grounding port PE. The DC output port includes: a first positive terminal for connecting the positive terminal of the DC bus electrolytic capacitor; a second positive terminal for connecting the positive terminal of a single electrolytic capacitor; and a common negative terminal for serving as a common reference terminal for the DC output.

[0009] A further feature of this invention is that the outer wall of the housing is provided with a heat dissipation outlet and a heat dissipation inlet, and the bottom of the housing is equipped with casters and directional wheels.

[0010] The beneficial technical effects of this utility model are as follows: 1. This application employs PLC control, using a pre-programmed sequential control sequence to achieve automatic charging and discharging of electrolytic capacitors. The operator only needs to set relevant parameters on the touchscreen to initiate the automatic charging process, requiring no manual intervention. This significantly improves charging efficiency, reduces operational complexity, and makes the charging process more intelligent and automated.

[0011] 2. This application features multiple operating modes, allowing for the charging of DC bus electrolytic capacitors or individual electrolytic capacitors. Through a graded control execution circuit (first-stage, second-stage, and third-stage contactors), AC power supplies of different voltage levels can be connected to the charging circuit as needed, accommodating electrolytic capacitors of varying voltage levels. This expands the scope of application, meeting the charging needs of different types and specifications of electrolytic capacitors, and providing greater versatility and flexibility.

[0012] 3. This application employs multiple protection measures to ensure the safety and reliability of the charging process. Specifically, the pre-charge resistor R1 limits the initial charging current to protect the electrolytic capacitor; the fuse FU provides overcurrent protection to prevent circuit failure; the discharge circuit safely releases charge through the discharge contactor KM4 and the discharge resistor R2; and the emergency stop button SBO ensures power cut-off in emergencies. These measures effectively extend the life of the electrolytic capacitor and ensure operator safety.

[0013] 4. This application is equipped with an AC voltmeter PV1 and a DC voltmeter PV2, which can monitor the output voltage of the autotransformer T1 and the voltage of the electrolytic capacitors in real time. Through the voltage switching relay KA, the monitoring of the DC bus electrolytic capacitor voltage or the voltage of a single electrolytic capacitor can be selected. The touchscreen 1 can display various parameters, allowing the operator to easily understand the charging status in real time. This achieves intelligent monitoring of the charging process, enabling the operator to adjust charging parameters promptly and ensure charging effectiveness.

[0014] 5. The intelligent charging and discharging device of this application can periodically charge and discharge electrolytic capacitors, effectively preventing electrolyte drying and dielectric aging, extending the service life of electrolytic capacitors, and thus reducing equipment maintenance and replacement costs.

[0015] In summary, this application achieves intelligent charging and discharging of electrolytic capacitors by adopting PLC control, multiple protection measures, intelligent monitoring, and a cabinet design. It has significant technical advantages such as high automation, diverse functions, safety and reliability, simple operation, convenient mobility, reduced costs, and extended service life. Attached Figure Description

[0016] Figure 1 A schematic diagram of the main circuit is shown.

[0017] Figure 2 A schematic diagram of the control loop circuit is shown.

[0018] Figure 3 A schematic diagram of the housing of this utility model is shown.

[0019] Attached reference numerals: 1. Touch screen; 2. Autotransformer T1 adjustment knob; 3. Precharge resistor R1 adjustment knob; 4. AC voltmeter PV1; 5. DC voltmeter PV2; 6. Emergency stop button SBO; 7. Main circuit power switch QF1; 8. Control circuit power switch QF2; 9. Main circuit power input port L / N; 10. DC output port; 11. Grounding port PE; 12. Heat dissipation exhaust vent; 13. Heat dissipation inlet vent; 14. Casters; 15. Fixed casters. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Please see Figure 1-3 This utility model provides a technical solution: an intelligent charging and discharging device for electrolytic capacitors, characterized in that it includes a main circuit and a control circuit, wherein the main circuit includes: The voltage regulating circuit includes an autotransformer T1, the input terminal of which is connected to an AC power supply, and an AC voltmeter PV1 is connected in parallel to its output terminal to monitor the output voltage of the autotransformer T1 after adjustment in real time. The voltage adjustment is achieved by manually rotating the adjustment button. The graded control execution circuit includes a transformer T2. The output terminal of the transformer T2 has multiple taps with different turns ratios, which are respectively connected to the control terminals of the first-stage contactor KM1, the second-stage contactor KM2, and the third-stage contactor KM3. Under the command of the control circuit, the first-stage contactor KM1, the second-stage contactor KM2, and the third-stage contactor KM3 connect AC power supplies of different voltage levels to the charging circuit as needed. During use, only one set of contactors is allowed to conduct at the same time (mutual exclusion control). The charging voltage level is adjusted by the control signal. The rectifier circuit includes a rectifier module D1 that converts regulated alternating current into direct current. An electrolytic capacitor charging circuit is provided, with its output terminal optionally connected to a DC bus electrolytic capacitor or a single electrolytic capacitor. The charging circuit for a single electrolytic capacitor is connected in series with a pre-charging resistor R1 to control the initial current. In practical use, the pre-charging resistor R1 is adjusted using a knob. The pre-charging resistor R1 is connected during the initial charging stage, and after pre-charging is complete, it switches to direct charging mode. The circuit also includes a DC voltmeter PV2 and a voltage switching relay KA for switching the monitoring signal source of the DC voltmeter PV2. When charging the electrolytic capacitor, the monitoring signal source of the DC voltmeter PV2 is either the DC bus electrolytic capacitor voltage or the voltage of a single electrolytic capacitor. The electrolytic capacitor discharge circuit includes a discharge contactor KM4 and a discharge resistor R2. The discharge circuit, through a control loop, activates the discharge contactor KM4, causing the electrolytic capacitor to discharge through the discharge resistor R2. A DC voltmeter PV2 monitors the voltage change across the electrolytic capacitor during discharge to ensure safe discharge. Once discharge is complete, the discharge contactor KM4 disconnects, ending the discharge process. This discharge circuit design effectively protects the electrolytic capacitor and extends the equipment's lifespan.

[0022] The control loop is powered by a 24V DC power supply circuit, and the AC input is converted into a regulated DC output by the control loop power switch QF2 and the 24V switching power supply module D2, which are connected to the AC power supply.

[0023] The control circuit includes a PLC. The digital input module of the PLC is connected to an emergency stop button SBO6 and a temperature control switch. The digital output module of the PLC is connected to a voltage switching relay KA, a first-position contactor KM1, a second-position contactor KM2, a third-position contactor KM3, a discharge contactor KM4, and a cooling fan FJ. The PLC, temperature control switch, emergency stop button SBO6, voltage switching relay KA, first-position contactor KM1, second-position contactor KM2, third-position contactor KM3, discharge contactor KM4, cooling fan, and touch screen are all powered by a 24V DC power supply.

[0024] The rectifier module D1, the first-speed contactor KM1, the second-speed contactor KM2, and the third-speed contactor KM3 are all connected in series with fuses FU to achieve overcurrent protection.

[0025] The charging and discharging device is a box, and a touch screen 1 is provided on the outer surface of the box. The touch screen 1 is connected to the PLC inside the box via an RS485 interface. The box is also equipped with an autotransformer T1 adjustment knob 2, a pre-charge resistor R1 adjustment knob 3, an AC voltmeter PV14, a DC voltmeter PV25, and an emergency stop button SBO6.

[0026] The enclosure is also equipped with a main circuit power switch QF17, a control circuit power switch QF28, a main circuit power input port L / N9, a DC output port 10, and a grounding port PE11. The DC output port 10 includes: a first positive terminal (+) for connecting the positive terminal of the DC bus electrolytic capacitor; a second positive terminal (+) for connecting the positive terminal of a single electrolytic capacitor; and a common negative terminal (-) for serving as a common reference terminal for DC output.

[0027] The outer wall of the box is provided with a heat dissipation outlet 12 and a heat dissipation inlet 13, and the bottom of the box is equipped with casters 14 and directional wheels (15).

[0028] The detailed connection methods are well-known in the field. The following mainly describes the working process: After the equipment is powered on by the main circuit power switch QF1 and the control circuit power switch QF2, it enters standby mode. The operator inputs the required charging and discharging parameters, such as target DC voltage, charging and discharging current, charging time, and discharging time, through the touch screen 1. After receiving these parameters, the PLC automatically or manually executes the corresponding operation according to the selected charging mode.

[0029] Automatic charging mode: In automatic charging mode, the PLC controls the autotransformer T1 adjustment knob 2 to adjust the input AC voltage according to preset charging parameters, and controls the pre-charging resistor R1 adjustment knob 3 to adjust the pre-charging current. This is to gradually increase the voltage and current, avoiding instantaneous large current surges and protecting the electrolytic capacitor. AC voltmeter PV1 displays the input AC voltage, and DC voltmeter PV2 monitors the rise in DC voltage of the electrolytic capacitor via voltage switching relay KA. The charging process is divided into three stages: stage one, stage two, and stage three, each with a set charging time. The corresponding working status indicator light on touchscreen 1 illuminates, indicating the current charging stage. The charging output can be connected to either a DC bus electrolytic capacitor or a single electrolytic capacitor. If a single electrolytic capacitor is selected, the pre-charging resistor R1 will be connected in series in the charging circuit to further limit the initial charging current. When the electrolytic capacitor reaches the set DC voltage, the charging completion indicator light on the touchscreen's automatic charging screen flashes and is accompanied by a buzzer sound. The charger's sequential control program ends, and the charger resets to its initial state.

[0030] Manual charging mode: In manual charging mode, the operator selects the first / second / third manual charging setting via the touchscreen and clicks the corresponding "Manual Charging Start" icon. The PLC controls the corresponding contactor to close, connecting the corresponding setting of the autotransformer T1 to the charging circuit. The operator slowly adjusts the autotransformer T1 adjustment knob 2 to gradually increase the output voltage, and monitors the electrolytic capacitor voltage using a DC voltmeter PV2 via the voltage switching relay KA. The charging output can also be connected to a DC bus electrolytic capacitor or a single electrolytic capacitor. If a single electrolytic capacitor is selected, the pre-charging resistor R1 will be connected in series in the charging circuit. The operator needs to continuously monitor the electrolytic capacitor voltage; when the rated voltage is reached, click the "Manual Charging Stop" icon on touchscreen 1 to stop charging.

[0031] Discharge process: To ensure the safety of electrolytic capacitors, a discharge operation must be performed after automatic or manual charging. The operator switches to the discharge interface on touchscreen 1, enters the desired discharge time, and then clicks the "Discharge Start" icon. This operation activates the discharge process.

[0032] When discharge begins, the discharge status indicator light on touchscreen 1 illuminates, indicating that the discharge operation has started. At this time, the discharge contactor KM4 is closed by the PLC, and the discharge resistor R2 in the connection circuit is connected in series between the first positive terminal and the second positive terminal on the DC output port 10, forming a complete discharge circuit. The electrolytic capacitor begins to discharge rapidly through the discharge resistor R2, and the current flows through the internal switch and the discharge resistor, safely releasing the charge in the capacitor.

[0033] During the discharge process, the PLC monitors the discharge current and voltage in real time to ensure the safety and stability of the discharge process. The discharge voltage is continuously displayed by the DC voltmeter PV2. When the set discharge time is reached, the PLC automatically controls the discharge contactor KM4 to open, cutting off the discharge circuit.

[0034] When the discharge is complete, the discharge status indicator light on the touchscreen goes out, and the DC voltmeter PV2 displays a value of zero, indicating that the charge inside the capacitor has been completely released and the capacitor has been safely discharged. This automated control process ensures the safety and controllability of the discharge process, effectively preventing potential risks from residual charge.

[0035] Temperature control: During equipment operation, the temperature control switch monitors the internal temperature in real time. As the equipment generates heat, the internal temperature gradually rises. Once the preset opening temperature threshold is reached, the temperature control switch automatically closes. After closing, the signal is transmitted to the control circuit of the cooling fan, energizing it and causing the fan to start operating. The cooling fan draws in cool outside air through the air inlet 13, where it circulates and absorbs the heat generated during operation. The hot air is then expelled through the air outlet 12, continuously circulating the air and effectively dissipating the heat generated during operation, thus lowering the internal temperature. As the cooling fan continues to operate, the internal temperature gradually decreases. When the temperature drops to the preset closing temperature threshold, the temperature control switch automatically opens, de-energizing the cooling fan control circuit and stopping the cooling fan.

[0036] Emergency Stop: In any emergency, the operator can press the emergency stop button (SBO) at any time to cut off the power to the equipment and ensure the safety of the operator.

[0037] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An intelligent charging and discharging device for electrolytic capacitors, characterized in that: It includes a main circuit and a control circuit, wherein the main circuit includes: The voltage regulating circuit includes a main circuit power switch QF1 and an autotransformer T1. The input terminal of the autotransformer T1 is connected to an AC power supply, and its output terminal is connected in parallel with an AC voltmeter PV1 for real-time monitoring of the output voltage after adjustment by the autotransformer T1. The graded control execution circuit includes a transformer T2. The output terminal of the transformer T2 has multiple taps with different turns ratios, which are respectively connected to the control terminals of the first-gear contactor KM1, the second-gear contactor KM2, and the third-gear contactor KM3. Under the command of the control circuit, the first-gear contactor KM1, the second-gear contactor KM2, and the third-gear contactor KM3 connect AC power supplies of different voltage levels to the charging circuit as needed. The rectifier circuit includes a rectifier module D1 that converts regulated alternating current into direct current. An electrolytic capacitor charging circuit, the output of which can be optionally connected to a DC bus electrolytic capacitor or a single electrolytic capacitor; wherein the single electrolytic capacitor charging circuit is connected in series with a pre-charging resistor R1 to control the initial current, and also includes a DC voltmeter PV2 and a voltage switching relay KA for switching the monitoring signal source of the DC voltmeter PV2. The electrolytic capacitor discharge circuit includes a discharge contactor KM4 and a discharge resistor R2.

2. The intelligent charging and discharging device for electrolytic capacitors according to claim 1, characterized in that: The control circuit includes a PLC, and the digital input module of the PLC is connected to an emergency stop button SBO and a temperature control switch; the digital output module of the PLC is connected to a voltage switching relay KA, a first-gear contactor KM1, a second-gear contactor KM2, a third-gear contactor KM3, a discharge contactor KM4, and a cooling fan FJ.

3. The intelligent charging and discharging device for electrolytic capacitors according to claim 1, characterized in that: The rectifier module D1, the first-speed contactor KM1, the second-speed contactor KM2, and the third-speed contactor KM3 are all connected in series with fuses FU to achieve overcurrent protection.

4. The intelligent charging and discharging device for electrolytic capacitors according to claim 1, characterized in that: The charging and discharging device is a box, and a touch screen (1) is provided on the outer surface of the box. The touch screen (1) is connected to the PLC inside the box via an RS485 interface. The box is also equipped with an autotransformer T1 adjustment knob (2), a pre-charge resistor R1 adjustment knob (3), an AC voltmeter PV1 (4), a DC voltmeter PV2 (5), and an emergency stop button SBO (6).

5. The intelligent charging and discharging device for electrolytic capacitors according to claim 4, characterized in that: The enclosure is also equipped with a main circuit power switch QF1 (7), a control circuit power switch QF2 (8), a main circuit power input port L / N (9), a DC output port (10), and a grounding port PE (11). The DC output port (10) includes: a first positive terminal for connecting the positive terminal of the DC bus electrolytic capacitor; a second positive terminal for connecting the positive terminal of a single electrolytic capacitor; and a common negative terminal for serving as a common reference terminal for DC output.

6. The intelligent charging and discharging device for electrolytic capacitors according to claim 4, characterized in that: The outer wall of the box is provided with a heat dissipation outlet (12) and a heat dissipation inlet (13), and the bottom of the box is equipped with casters (14) and directional casters (15).

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