Electrolytic capacitor detection device of frequency converter
By designing an electrolytic capacitor detection device for inverters, using comparative circuits and relay circuits to achieve automatic detection and power failure protection, the heating, shortening of life and potential explosion hazards caused by the reverse connection of electrolytic capacitors in inverters is solved, and product quality and reliability are improved.
Patent Information
- Application Number
- CN202421756709.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-24
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-07-24
AI Technical Summary
The reverse connection of the electrolytic capacitor in the inverter causes the capacitance to generate heat, shorten its life, increase its cost, and there is a potential explosion risk.
Design an electrolytic capacitance detection device for inverters, including power supply module, filter boost module, inverter under test, detection module, protection module, circuit breaker and contactor. The status of the main circuit is monitored by the comparison circuit in the detection module, and the contactor circuit of the protection module is controlled through the relay circuit, and the connection between the main circuit contactor and the back-end device is disconnected to realize automatic detection and power-off protection.
It realizes automatic detection of whether the electrolytic capacitor is connected in reverse, ensures the correct installation of the electrolytic capacitor, and takes power-off protection measures, solves the problem of shortening of the life cycle caused by the misconnection of the polarity of the electrolytic capacitor, and improves the product quality and reliability of the inverter.
Smart Images
Figure CN222994644U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of frequency converters, and particularly to an electrolytic capacitor detection device for a frequency converter. Background Art
[0002] A frequency converter is a voltage-frequency regulation controller, which plays a role in motor speed regulation in industrial production. If the electrolytic capacitor is reversely connected at both ends during the production process of a traditional frequency converter, it will cause permanent damage to the frequency converter. In actual production applications, the situation of reverse connection of the electrolytic capacitor polarity often occurs and is difficult to detect. When the electrolytic capacitor is reversely connected for a period of time in industrial applications, it often causes the electrolytic capacitor to fail, affecting the life of the reversely connected electrolytic capacitor, thereby affecting the normal use of the frequency converter and reducing the service life and quality of the frequency converter. Content of the Utility Model
[0003] To solve the above problems, the utility model provides an electrolytic capacitor detection device for a frequency converter, which solves the problems such as capacitor heating, shortened life, and increased cost caused by reverse connection of the electrolytic capacitor in the frequency converter, and at the same time prevents potential dangers such as explosion caused by reverse connection of the electrolytic capacitor.
[0004] To achieve the above purpose, the technical solution provided by the utility model is:
[0005] An electrolytic capacitor detection device for a frequency converter includes a power supply module A, a filter and boost module B, a frequency converter to be measured C, a detection module E, a protection module D, a circuit breaker QF, and a contactor KM. The grid power supply is connected to the main contact of the contactor KM through the circuit breaker QF. The contactor KM is connected to the power supply module A. The power supply module A is connected to the filter and boost module B. The filter and boost module B is connected to the frequency converter to be measured C. The detection module E is connected to the power supply module A. The detection module E is connected to the protection module D. The protection module D is connected to the circuit breaker QF.
[0006] Further, a current measurement and control device is built into the power supply module A to detect the current state of the backend device; the current measurement and control device is connected to a comparator on the detection module E.
[0007] Further, the detection module E uses a comparison circuit to monitor the state of the main circuit.
[0008] Further, the relay circuit in the detection module E controls the contactor circuit of the protection module D, and the main circuit contactor is disconnected from the backend device through the contactor circuit.
[0009] Compared with the prior art, the beneficial effect of the utility model is that this device can automatically detect whether the electrolytic capacitor is reversely connected, determine the correctness of the installation of the electrolytic capacitor and take power-off protection measures, solve the problem of shortened life cycle of the electrolytic capacitor caused by wrong connection of the electrolytic capacitor polarity, and improve the product quality and reliability of the frequency converter. Description of the Drawings
[0010] Figure 1 is a schematic diagram of a detection device for electrolytic capacitors of a frequency converter provided by the present utility model;
[0011] Figure 2 is the electrical schematic diagram of the filter boost module B of the present utility model;
[0012] Figure 3 is the electrical schematic diagram of the protection module D of the present utility model;
[0013] Figure 4 is the electrical schematic diagram of the detection module E of the present utility model. Detailed Description of the Preferred Embodiment
[0014] The present utility model will be further described in detail below with reference to the drawings and the detailed description of the preferred embodiment.
[0015] Figure 1 is a schematic diagram of a detection device for electrolytic capacitors of a frequency converter provided by the present utility model. As shown in Figure 1 a detection device for electrolytic capacitors of a frequency converter includes: a power supply module A, a filter boost module B, a frequency converter under test C, a detection module E, a protection module D, a circuit breaker QF, and a contactor KM. The grid power supply is connected to the main contacts of the contactor KM through the circuit breaker QF. The contactor KM is connected to the power supply module A. The power supply module A is connected to the filter boost module B. The filter boost module B is connected to the frequency converter under test C. The detection module E is connected to the power supply module A. The detection module E is connected to the protection module D. The protection module D is connected to the circuit breaker QF.
[0016] Figure 2 is the electrical schematic diagram of the filter boost module B of the present utility model. As shown in Figure 1 and as shown in Figure 2 the frequency converter under test C is connected to the filter through a step-up transformer T. One ends of three BBC capacitors C1, C2, and C3 on the filter are connected in a star connection mode, and the other ends are first connected to an inductor and then connected to the power supply module A.
[0017] Figure 3 is the electrical schematic diagram of the protection module D of the present utility model. As shown in Figure 1 and Figure 3 a contactor coil KM-1 in the protection module D has one end connected to one phase of QF, and the other end connected to a push-button switch SB. A normally closed auxiliary contact KM-2 of the contactor is connected in parallel to the push-button switch SB, and is connected to a normally closed auxiliary contact JK-2 of a relay on the detection module E. The other end of the normally closed auxiliary contact JK-2 of the relay is connected to another phase of the circuit breaker QF.
[0018] Figure 4 is the electrical schematic diagram of the detection module E of the present utility model. As shown inFigure 1 and Figure 4 As shown in Figure 4 , the detection module E is connected to the power supply module A. The comparator U1 is connected to the driving resistor R1, the driving resistor R1 is connected to the triode Q1. The collector of the triode Q1 is a reference voltage Vcc2, and the emitter of the triode Q1 is connected to the capacitor C4 to play a role in delaying the detection signal. The resistor R2 is respectively connected to the emitter of the triode Q1 and the base of the triode Q2, the resistor R3 is connected between the base and the emitter of the triode Q2, and the collector of the triode Q2 is connected to the coil JK-1 of the relay, and a reference voltage Vcc3 is connected behind the coil.
[0019] Specific implementation steps:
[0020] 1. As Figure 1 and Figure 3 shown, the utility model first closes the circuit breaker QF and then presses the push-button switch SB to make the contactor in the protection module D energized to work. The coil KM-1 is attracted, and the auxiliary contact KM-2 is closed. At this time, the power supply module A obtains power supply from the power grid, and the power supply module A is operated. The power supply module A can adjust the voltage and frequency. As Figure 1 and Figure 2 shown, the sine PWM waveform output by the power supply module A is filtered by the LC filter, and then the step-up transformer T makes the bus voltage reach the working voltage of the measured frequency converter C and makes it work.
[0021] 2. When the internal electrolytic capacitor of the measured frequency converter C has the reverse polarity, an abnormal current will be generated. The abnormal current is detected by the current sensor inside the power supply module A. At the same time, the power supply module A monitors the output current size in real time and sends the signal data to the detection module E. As Figure 4 shown, the comparator U1 inside the detection module E judges through the fed-back abnormal current signal and the reference voltage Vcc1. If the abnormal current exceeds the reference voltage set by the comparator U1, the output end of the comparator will output a high-level signal to drive the triode to make the relay JK-1 energized to work, and send the signal to the protection module D. The relay auxiliary contact JK-2 in the protection module D is disconnected, then the contactor coil KM-1 loses power, the main contact of the contactor KM is disconnected, and the power supply module A is powered off, thus protecting the devices on the main circuit and the frequency converter. In order to make the relay JK-1 energized to work and normally send the protection signal to perform the next power-off operation, when the triode Q1 is turned on, a capacitor C4 is added to the emitter-base of the triode Q1, so that the triode Q2 has enough conduction time to make the relay JK-1 work and send out an abnormal state signal to disconnect the main circuit power supply. If the electrolytic capacitor polarity is not connected wrongly and the main circuit is normal, the positive-phase input terminal of the voltage input comparator in the detection module E is less than the given reference voltage Vcc1. At this time, the comparator outputs a low level and does not conduct the triode connected behind, which can indicate that the main circuit is in a normal working state.
[0022] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several modifications and improvements can be made, which should also be regarded as falling within the protection scope of the present utility model.
Claims
1. An electrolytic capacitor detection device for a frequency converter, comprising a power module A, a filter boost module B, a tested frequency converter C, a detection module E, a protection module D, a circuit breaker QF, and a contactor KM, characterized in that: The grid power supply is connected to the main contacts of the contactor KM through the circuit breaker QF, the contactor KM is connected to the power module A, the power module A is connected to the filter boost module B, the filter boost module B is connected to the measured inverter C, the detection module E is connected to the power module A, the detection module E is connected to the protection module D, and the protection module D is connected to the circuit breaker QF.
2. The electrolytic capacitor detection device for a frequency converter according to claim 1, characterized in that: A current measurement and control device is built into the three-phase output terminal of the power module A to detect the current state of the back-end equipment; the current measurement and control device is connected to the comparator on the detection module E.
3. The electrolytic capacitor detection device for a frequency converter according to claim 1, characterized in that: The detection module E uses a comparison circuit to monitor the status of the main circuit.
4. The electrolytic capacitor detection device for a frequency converter according to claim 1, characterized in that: The relay circuit in the detection module E controls the contactor circuit of the protection module D, and controls the main circuit contactor to disconnect from the back-end equipment through the contactor circuit.