Automatic detection system and method for parameters of thin film capacitor

Abstract

The invention discloses an automatic detection system and method for parameters of a thin film capacitor, and belongs to the field of automatic measurement of element parameters. The automatic detection system comprises an upper computer, a voltage source, a constant temperature and humidity test box, a control module and a measurement module, the thin film capacitor test sample is placed in the constant temperature and humidity test box and is connected with the voltage source and the measurement module; the control module is connected with the thin-film capacitor test sample and comprises a high-voltage circuit breaker, a timer and a PLC, and the PLC receives an instruction of the upper computer and sends a control signal to the timer; the timer controls the high-voltage circuit breaker to periodically cut off the connection between the thin-film capacitor test sample and the voltage source and the connection between the thin-film capacitor test sample and the measurement module; and the measurement module is connected with the to-be-measured sections of the thin film capacitor test sample one by one, measures parameters of the to-be-measured sections and sends parameter measurement data to the upper computer for storage. The effects of convenient measurement and high test accuracy are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of automatic measurement of component parameters, and more specifically, relates to an automatic detection system and method for film capacitor parameters. Background Art

[0002] Film capacitors will experience electrothermal aging during long-term use, causing changes in the electrothermal performance parameters of capacitor components, thereby threatening the normal operation of the entire machine and the entire power line system. Therefore, continuous monitoring and evaluation of the status of film capacitors is essential to ensure the reliability and safety of the system.

[0003] By collecting and analyzing the data of electrothermal parameters, the remaining life and potential failure risk of capacitors can be predicted, thereby achieving predictive maintenance and reducing unexpected downtime. Accelerated aging tests play an important basic role in the performance evaluation, life prediction, reliability analysis and structural optimization design of electronic components, and have been widely used.

[0004] However, the traditional accelerated aging test method is discontinuous, and only a few measurements are performed during a long aging test. However, the few measured data only represent the trend of change, not a complete degradation characteristic. At the same time, in these tests, long interruptions may cause some electrothermal parameter values ​​to change in an unexpected range. Therefore, there is an urgent need for an automatic parameter detection method for film capacitors, which is of great significance for accurately monitoring and evaluating the status of film capacitors. Summary of the invention

[0005] In view of the defects of the related art, the purpose of the present invention is to provide a system and method for automatic detection of film capacitor parameters, aiming to solve the problem that the existing parameter measurement method of film capacitors relies on continuous intermittent testing to obtain measurement data during accelerated aging tests, thereby leading to large errors in the measured electrothermal parameter values.

[0006] To achieve the above-mentioned object, in a first aspect, the present invention provides an automatic detection system for film capacitor parameters, comprising: a host computer, a voltage source, a constant temperature and humidity test chamber, a control module and a measurement module;

[0007] A film capacitor test sample is placed in the constant temperature and humidity test chamber, and the film capacitor test sample is connected to the voltage source and the measurement module; the constant temperature and humidity test chamber is used to maintain the temperature and humidity of the environment in which the film capacitor test sample is located; the voltage source is used to apply voltage to the film capacitor test sample for testing;

[0008] The control module is connected to the film capacitor test sample, and the control module includes a high-voltage circuit breaker, a timer and a PLC controller. The PLC controller is used to receive instructions from a host computer and send a control signal to the timer. The timer is used to control the high-voltage circuit breaker to periodically disconnect the connection between the film capacitor test sample and the voltage source and the connection between the film capacitor test sample and the measurement module according to the control signal;

[0009] The measuring module is used to connect the sections to be tested of the film capacitor test sample one by one, measure the parameters of the film capacitor test sample, and send the parameter measurement data to the host computer for storage.

[0010] Optionally, the timer is used to start timing from the receipt of a control signal, and the timer is used to start timing from the receipt of a control signal, and within the set cycle T1 time, control the high-voltage circuit breaker to connect the voltage source and the film capacitor test sample, and disconnect the measuring module and the film capacitor test sample; after reaching the set cycle T1 time, control the high-voltage circuit breaker to disconnect the voltage source and the film capacitor test sample, and connect the measuring module and the film capacitor test sample, and at the same time, reset the timer.

[0011] Optionally, the host computer is also used to determine whether the film capacitor test sample has reached the end of life condition, or whether the test time has reached T2 hours after receiving the parameter measurement data; if so, the host computer controls the end of the test.

[0012] Optionally, the measurement module includes a multiplexer, a temperature sensor, a thermal image collection device and an electrical parameter measurement device;

[0013] The multiplexer is connected to the temperature sensor, the thermal image collecting device and the electrical parameter measuring device;

[0014] The temperature sensor is used to measure the surface temperature of the film capacitor test sample;

[0015] The thermal image collecting device is used to measure the surface thermal state of the film capacitor test sample and perform thermal state imaging;

[0016] The electrical parameter measuring device is used to measure the electrical parameters of the film capacitor test sample.

[0017] Optionally, the automatic detection system further comprises: a protection device;

[0018] The protection device is arranged between the voltage source and the film capacitor test sample to prevent damage to the circuit and the device caused by overvoltage or overcurrent and to perform circuit protection.

[0019] Optionally, the voltage source includes a DC voltage source and an AC voltage source.

[0020] Optionally, the automatic detection system further comprises: a high voltage switch;

[0021] The high-voltage switch is connected to the host computer and the voltage source, and is used to receive signals from the host computer and selectively connect the DC voltage source or the AC voltage source to the circuit.

[0022] Optionally, the constant temperature and humidity test box is provided with a wire outlet hole for leading out the sections to be tested of multiple film capacitor test samples through wires.

[0023] In a second aspect, the present invention further provides a method for automatically detecting electrothermal parameters of a film capacitor, which is applied to the automatic detection system as described in any one of the first aspects, comprising:

[0024] Place the film capacitor test sample in a constant temperature and humidity test chamber, and adjust the temperature and humidity of the constant temperature and humidity test chamber to the set values;

[0025] Sending a control signal to the PLC controller through the host computer to periodically disconnect the connection between the film capacitor test sample and the voltage source and the connection between the film capacitor test sample and the measurement module;

[0026] The parameter measurement data of the film capacitor test sample is obtained from the host computer.

[0027] Compared with the prior art, the above technical solution conceived by the present invention can achieve the following beneficial effects:

[0028] 1. The present invention provides an automatic detection system for film capacitor parameters. The circuit connection at both ends of the film capacitor test sample is periodically controlled by the timer and high-voltage circuit breaker in the control module, so that the film capacitor test sample is periodically and alternately connected to the voltage source power supply circuit and the measurement circuit. The parameters of the film capacitor test element under test are continuously and automatically monitored during the accelerated aging test, and the errors caused by the interruption of the aging process are eliminated, which greatly reduces the invalid time in the test. By placing the film capacitor test sample in a constant temperature and humidity test box, the stability of the test conditions can be guaranteed and it is not affected by factors such as the external environment. The automatic detection system provided by the present invention is safe and simple, the measurement method is convenient, the operability is strong, and the test results are highly accurate.

[0029] 2. The present invention provides an automatic detection system for film capacitor parameters. The film capacitor test sample can be selectively connected to a DC voltage source or an AC voltage source through a high-voltage switch to actively select the type of test voltage; through the custom timer cycle, the custom measurement time and interval threshold are realized to meet a variety of test conditions.

[0030] 3. The present invention provides an automatic detection system for film capacitor parameters, wherein the measurement module includes a multiplexer, a temperature sensor, a thermal image collection device, and an electrical parameter measurement device. The multiplexer is connected to the test section of the film capacitor test sample, and the surface temperature, surface thermal state imaging, and electrical parameters of the film capacitor test sample are measured simultaneously. When measuring parameters, the multiplexer selects the test sections of different film capacitor test samples one by one, and multiple groups of data can be measured at one time to ensure the accuracy of the data. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of an automatic detection system for film capacitor parameters provided by the present invention;

[0032] Figure 2 The present invention provides a flow chart of a method for automatically detecting film capacitor parameters. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] The contents involved in the above embodiment are described below in conjunction with a preferred embodiment.

[0035] Embodiment 1

[0036] like Figure 1 As shown, the present invention provides an automatic detection system for film capacitor parameters, including: a host computer, a voltage source, a constant temperature and humidity test chamber, a control module and a measurement module;

[0037] A film capacitor test sample is placed in the constant temperature and humidity test chamber, and the film capacitor test sample is connected to the voltage source and the measurement module; the constant temperature and humidity test chamber is used to maintain the temperature and humidity of the environment in which the film capacitor test sample is located; the voltage source is used to apply voltage to the film capacitor test sample for testing;

[0038] The control module is connected to the film capacitor test sample, and the control module includes a high-voltage circuit breaker, a timer and a PLC controller. The PLC controller is used to receive instructions from a host computer and send a control signal to the timer. The timer is used to control the high-voltage circuit breaker to periodically disconnect the connection between the film capacitor test sample and the voltage source and the connection between the film capacitor test sample and the measurement module according to the control signal;

[0039] The measuring module is used to connect the sections to be tested of the film capacitor test sample one by one, measure the parameters of the film capacitor test sample, and send the parameter measurement data to the host computer for storage.

[0040] In response to the problems existing in the existing methods for detecting the electrothermal parameters of thin film capacitors, an embodiment of the present invention adopts an automatic detection system for thin film capacitor parameters to accurately monitor and evaluate the status of thin film capacitors, eliminate errors caused by interruptions in the aging process, and greatly reduce the invalid time in the test.

[0041] An automatic detection system for film capacitor parameters provided by an embodiment of the present invention is constructed, and several film capacitor test samples of the same type are prepared. In this embodiment, the film capacitor test samples are film capacitor components; the initial performance parameters of the film capacitor components are measured, and the film capacitor test samples of the film capacitor components are placed in a constant temperature and humidity test chamber, and the temperature and humidity of the constant temperature and humidity test chamber are adjusted to set values. The overall test circuit is connected, the host computer is started to send a test signal, the voltage source applies voltage to the film capacitor test sample, and the host computer sends a control signal to the PLC controller in the control module. The PLC controller sends a control signal to the timer through a built-in program, the timer starts and begins timing, and the timer controls the high-voltage circuit breaker to periodically disconnect the power supply circuit between the film capacitor test sample and the voltage source and the measurement circuit between the film capacitor test sample and the measurement module; specifically: within the timer setting cycle, the voltage source and the power supply circuit of the film capacitor test sample are connected, and the measurement circuit of the film capacitor test sample and the measurement module are disconnected. At this time, the voltage source continues to apply voltage to the film capacitor test sample; when the timer setting cycle is reached, the voltage source and the power supply circuit of the film capacitor test sample are disconnected, and the measurement circuit of the film capacitor test sample and the measurement module are connected. At this time, the measurement module performs parameter measurement on the film capacitor test sample.

[0042] When measuring parameters, the measuring module selects different sections of the film capacitor test samples to be tested for connection, and can measure multiple groups of data at one time to ensure the accuracy of the data. The parameter measurement data is sent to the host computer for storage.

[0043] refer to Figure 2Optionally, the timer is used to start timing from the time the control signal is received, and within the set cycle T1 time, control the high-voltage circuit breaker to connect the voltage source and the film capacitor test sample, and disconnect the measurement module and the film capacitor test sample; after reaching the set cycle T1 time, control the high-voltage circuit breaker to disconnect the voltage source and the film capacitor test sample, connect the measurement module and the film capacitor test sample, and at the same time, reset the timer.

[0044] Optionally, the host computer is also used to determine whether the film capacitor test sample has reached the end of life condition, or whether the test time has reached T2 hours after receiving the parameter measurement data; if so, the host computer controls the end of the test.

[0045] Furthermore, after the test is finished, the host computer is also used to generate parameter curves and images according to the parameter measurement data, and perform status evaluation and analysis on the film capacitor test samples.

[0046] In this embodiment, T1 is set to 30 minutes, and T2 is set to 500 hours.

[0047] Optionally, the measurement module includes a multiplexer, a temperature sensor, a thermal image collection device and an electrical parameter measurement device;

[0048] The multiplexer is connected to the temperature sensor, the thermal image collecting device and the electrical parameter measuring device;

[0049] The temperature sensor is used to measure the surface temperature of the film capacitor test sample;

[0050] The thermal image collecting device is used to measure the surface thermal state of the film capacitor test sample and perform thermal state imaging;

[0051] The electrical parameter measuring device is used to measure the electrical parameters of the film capacitor test sample.

[0052] When measuring parameters, the constant temperature and humidity test box is provided with a wire outlet hole for leading out the sections to be tested of multiple film capacitor test samples through wires. One end of the multiplexer selects the sections to be tested of different film capacitor test samples one by one for connection. At the same time, the other end of the multiplexer is connected to the temperature sensor, the thermal image collection device and the electrical parameter measurement device to measure the surface temperature, surface thermal state imaging and electrical parameters of the film capacitor test samples respectively and simultaneously. A variety of data can be obtained in one measurement test. Specifically, the surface temperature data of the film capacitor test element is measured by the temperature sensor, the capacitance and ESR value of the film capacitor test element are measured by the electrical parameter measurement device, the thermal image collection device performs surface thermal state imaging of the film capacitor test sample, and the above measurement values ​​and images are automatically uploaded to the host computer system for recording and storage.

[0053] Optionally, the automatic detection system further comprises: a protection device;

[0054] The protection device is arranged between the voltage source and the film capacitor test sample to prevent damage to the circuit and the device caused by overvoltage or overcurrent and to perform circuit protection.

[0055] Optionally, the voltage source includes a DC voltage source and an AC voltage source.

[0056] Optionally, the automatic detection system further comprises: a high voltage switch;

[0057] The high-voltage switch is connected to the host computer and the voltage source, and is used to receive signals from the host computer and selectively connect the DC voltage source or the AC voltage source to the circuit.

[0058] The high-voltage switch selectively switches on or off the DC voltage source or the AC voltage source according to the control signal of the host computer, and can actively set different voltage conditions, thereby realizing tests and measuring data under various conditions.

[0059] In a specific embodiment, the film capacitor test sample uses a metallized film capacitor element, and the measured initial capacitance is 470μF. The host computer selects the test voltage as 305V rms The AC power supply is set at 85℃ and 85% relative humidity in the constant temperature and humidity test chamber. The timer period is set to 30 minutes, and the end-of-life condition is when the capacitance decreases by more than 5% of the initial value. The upper computer obtains the curve of the percentage of capacitance decrease and the surface temperature change over time of the electronic components, and monitors the thermal state imaging of the component surface in real time. Compared with the traditional accelerated aging method, the measurement cycle is improved from the previous day or hour level accuracy to the minute level.

[0060] The embodiment of the present invention cooperates with the timer and high-voltage circuit breaker in the control module to periodically control the circuit connection at both ends of the film capacitor test sample, so that the film capacitor test sample is periodically and alternately connected to the voltage source power supply circuit and the measurement circuit, and the parameters of the film capacitor test element under test are continuously and automatically monitored during the accelerated aging test. The errors caused by the interruption also greatly reduce the invalid time in the test. By placing the film capacitor test sample in a constant temperature and humidity test box, the stability of the test conditions can be guaranteed without being disturbed by factors such as the external environment. When measuring parameters, the measurement module selects different sections of the film capacitor test samples to be tested for connection, and multiple groups of data can be measured at one time to ensure the accuracy of the data. The existing film capacitor parameter measurement method relies on continuous and intermittent testing to obtain measurement data during the accelerated aging test, thereby causing the technical problem that the measured electrothermal parameter value has a large error, and the beneficial effects of safety and simplicity, convenient measurement method, strong operability, and high accuracy of test results are achieved.

[0061] Embodiment 2

[0062] The present invention further provides a method for automatically detecting electrothermal parameters of a film capacitor, which is applied to the automatic detection system as described in any one of the first embodiments, comprising:

[0063] Place the film capacitor test sample in a constant temperature and humidity test chamber, and adjust the temperature and humidity of the constant temperature and humidity test chamber to the set values;

[0064] Sending a control signal to the PLC controller through the host computer to periodically disconnect the connection between the film capacitor test sample and the voltage source and the connection between the film capacitor test sample and the measurement module;

[0065] The parameter measurement data of the film capacitor test sample is obtained from the host computer.

[0066] An automatic detection method for electrothermal parameters of a film capacitor provided in an embodiment of the present invention is implemented based on an automatic detection system for electrothermal parameters of a film capacitor provided in any embodiment of the present invention, and has corresponding beneficial effects.

[0067] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic detection system for film capacitor parameters, characterized in that: include: Host computer, voltage source, constant temperature and humidity test chamber, control module and measurement module; A film capacitor test sample is placed in the constant temperature and humidity test chamber, and the film capacitor test sample is connected to the voltage source and the measurement module; the constant temperature and humidity test chamber is used to maintain the temperature and humidity of the environment in which the film capacitor test sample is located; the voltage source is used to apply voltage to the film capacitor test sample for testing; The control module is connected to the film capacitor test sample, and the control module includes a high-voltage circuit breaker, a timer and a PLC controller. The PLC controller is used to receive instructions from a host computer and send a control signal to the timer. The timer is used to control the high-voltage circuit breaker to periodically disconnect the connection between the film capacitor test sample and the voltage source and the connection between the film capacitor test sample and the measurement module according to the control signal; The measuring module is used to connect the sections to be tested of the film capacitor test sample one by one, measure the parameters of the film capacitor test sample, and send the parameter measurement data to the host computer for storage.

2. The automatic detection system according to claim 1, characterized in that: The timer is used to start timing from the time the control signal is received, and within the T1 time of the set cycle, control the high-voltage circuit breaker to connect the voltage source and the film capacitor test sample, and disconnect the measuring module and the film capacitor test sample; after reaching the T1 time of the set cycle, control the high-voltage circuit breaker to disconnect the voltage source and the film capacitor test sample, connect the measuring module and the film capacitor test sample, and at the same time, reset the timer.

3. The automatic detection system according to claim 2, characterized in that: The host computer is also used to determine whether the film capacitor test sample has reached the end of life condition or whether the test time has reached T2 hours after receiving the parameter measurement data; if so, the host computer controls the end of the test.

4. The automatic detection system according to claim 1, characterized in that: The measuring module includes a multiplexer, a temperature sensor, a thermal image collecting device and an electrical parameter measuring device; The multiplexer is connected to the temperature sensor, the thermal image collecting device and the electrical parameter measuring device; The temperature sensor is used to measure the surface temperature of the film capacitor test sample; The thermal image collecting device is used to measure the surface thermal state of the film capacitor test sample and perform thermal state imaging; The electrical parameter measuring device is used to measure the electrical parameters of the film capacitor test sample.

5. The automatic detection system according to claim 1, characterized in that: The automatic detection system also includes: a protection device; The protection device is arranged between the voltage source and the film capacitor test sample to prevent damage to the circuit and the device caused by overvoltage or overcurrent and to perform circuit protection.

6. The automatic detection system according to claim 1, characterized in that: The voltage source includes a direct current voltage source and an alternating current voltage source.

7. The automatic detection system according to claim 6, characterized in that: The automatic detection system also includes: a high voltage switch; The high-voltage switch is connected to the host computer and the voltage source, and is used to receive signals from the host computer and selectively connect the DC voltage source or the AC voltage source to the circuit.

8. The automatic detection system according to claim 1, characterized in that: The constant temperature and humidity test box is provided with a wire outlet hole on its box body, which is used to lead out the sections to be tested of multiple film capacitor test samples through wires.

9. An automatic detection method for electrothermal parameters of a film capacitor, applied to the automatic detection system according to any one of claims 1 to 8, characterized in that: include: Place the film capacitor test sample in a constant temperature and humidity test chamber, and adjust the temperature and humidity of the constant temperature and humidity test chamber to the set values; Sending a control signal to the PLC controller through the host computer to periodically disconnect the connection between the film capacitor test sample and the voltage source and the connection between the film capacitor test sample and the measurement module; The parameter measurement data of the film capacitor test sample is obtained from the host computer.

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