CN111366787B - Method and equipment for testing direct current resistance of capacitor discharge coil - Google Patents

Abstract

The invention provides a method for testing the direct current resistance of a discharge coil of a capacitor, which is used for detecting the direct current resistance of the discharge coil in a high-voltage parallel capacitor device and comprises the following steps: the method comprises a testing wiring step, a testing control step, a target data acquisition step and a testing calculation step, wherein adjustable direct current voltage is applied to two ends of a discharging coil to be tested, a current sensor is adopted to select a tested branch circuit, and a processor and a corresponding relay are used for controlling so as to realize accurate measurement of milliampere level small current, so that the direct current resistance of the discharging coil is obtained, and the method has good implementation convenience. In addition, the invention also provides a device for testing the direct current resistance of the capacitor discharge coil.

Description

A method and equipment for testing the DC resistance of a capacitor discharge coil

technical field

The invention relates to the field of detection, in particular to a method and equipment for testing the DC resistance of a capacitor discharge coil.

Background technique

The high-voltage parallel capacitor device is an important device for realizing reactive power compensation in the power system, and the purpose of reactive power regulation is achieved by switching capacitor banks. However, when the capacitor bank is removed, the presence of residual charges in the capacitive elements leads to high transient overvoltages, compromising the insulation of the switchgear. To this end, a discharge coil needs to be connected in parallel at both ends of the parallel capacitor, so that the residual charge in the parallel capacitor can be quickly discharged. , so it is widely used in distribution network.

The standard stipulates that the capacitor discharge coil should reduce the residual voltage of the capacitor from the rated value to below 50V within 5s from the start of discharge. If the capacitor discharge coil fails, on the one hand, it is easy to cause the capacitor bank to fail to discharge the residual charge normally, thus endangering the safety of equipment and personal safety; Therefore, the measurement of the capacitor discharge coil is particularly important, and the measurement of its DC resistance is a routine test item required by the regulations.

In actual measurement, on the one hand, due to the large inductance of the discharge coil, its equivalent DC resistance is usually 2kΩ-4kΩ, so the measurement current is only milliampere, which cannot be directly measured with a multimeter; on the other hand, due to the existence of capacitor banks For multiple series and parallel branches, it is impossible to measure a single discharge coil with a multimeter. In addition, due to the effect of the stored charge in the capacitor, it takes a long time for the measurement process to reach a steady state, and even LC oscillations may occur. At present, the existing discharge coil measurement method can only be measured by using a high-precision DC resistance measuring instrument alone after removing the measured discharge coil. The disadvantage is that it is cumbersome and time-consuming to disconnect and reassemble, and it increases the work of maintenance personnel. quantity. Therefore, there is an urgent need for a new DC resistance measurement technology of the capacitor discharge coil, which can achieve the purpose of fast and accurate measurement without removing the wires.

SUMMARY OF THE INVENTION

In order to achieve the purpose of quickly and accurately measuring the discharge coil of a high-voltage parallel capacitor device without removing the wire, the present invention provides a method and device for testing the DC resistance of the capacitor discharge coil.

A method for testing the DC resistance of a capacitor discharge coil is used for DC resistance detection of a discharge coil in a high-voltage parallel capacitor device, the high-voltage parallel capacitor device comprising a discharge coil arranged in parallel on the capacitor device;

include:

Test wiring step: connect the first output interface and the second output interface of the output interface group of the relay control circuit to both ends of the branch where the discharge coil is located to form a test main circuit, and clamp the current sensor on the test main circuit;

Test control step: the processor module controls the test switch on the test branch of the relay control circuit to close, the test branch is connected to the test main circuit, and the test branch includes a test switch;

The target data acquisition step: in the precise mode, the processor module controls the adjustable working power supply to output a DC adjustable power supply voltage _US , where the adjustable power supply voltage US is the input voltage of the input interface _group of the relay control circuit, The output voltage of the output interface group of the relay control circuit is the same as _US ;

The current sensor converts the current I _f of the main test loop into a real-time feedback voltage U _f and sends it back to the processor module;

The processor module adjusts the adjustable power supply voltage U _S according to the real-time feedback voltage U _f until the real-time feedback voltage U _f is equal to the correction voltage U _pk of the kth group of correction data in the data table; at this time, the The adjustable power supply voltage U _S is the target voltage U _S0 , the real-time feedback voltage U _f is the target feedback voltage U _f0 , and in the kth group of correction data, the correction current I _pk corresponding to the correction voltage U _pk is target current I _f0 ;

The processor module obtains a set of target data, and the target data is {U _S0 , U _f0 , I _f0 };

Test calculation step: the processor module calculates the DC resistance of the discharge coil

The data table includes n groups of correction data {U _pi , I _pi , R _pi }, i=1,2,...,n, where U _pi is the correction voltage of the i-th group of correction data, and I _pi is the i-th Correction current of the group of correction data, R _pi is the correction resistance value of the i-th group of correction data, k∈{1,2,…,n}.

In an optional embodiment, the data table is obtained based on a data table generation method, and the data table generation method includes:

Calibration wiring step: short-circuit the first output interface and the second output interface of the output interface group of the relay control circuit to form a closed calibration main loop, and clamp the current sensor on the calibration main loop;

The correction control step: the processor module controls the correction switch on the i-th correction branch in the n correction branches of the relay control circuit to close, and the correction switches on the other correction branches in the n correction branches are kept open, The i-th correction branch is connected to the correction main circuit, and the i-th correction branch includes a correction resistor R _pi and a corresponding correction switch;

所述可调电源电压

为所述继电器控制电路的输入接口组的输入电压，所述校正电阻R_pi两端电压为

所述电流传感器将所述校正主回路的校正电流I_pi转化为实时反馈的校正电压U_pi回传至处理器模块；Correction data acquisition steps: The processor module controls the adjustable power supply voltage of the adjustable working power supply to output DC

The adjustable supply voltage

is the input voltage of the input interface group of the relay control circuit, and the voltage across the correction resistor R _pi is

The current sensor converts the correction current I _pi of the correction main circuit into a real-time feedback correction voltage U _pi and sends it back to the processor module;

Correction calculation steps: the processor module calculates the correction current of the main circuit for correction

Obtain the i-th set of correction data {U _pi , I _pi , R _pi };

The calibration wiring step, the calibration control step, the calibration data acquisition step, and the calibration calculation step are repeatedly performed to obtain n sets of calibration data.

In an optional implementation manner, the target data acquisition step further includes:

In the fast mode, a calibration function curve f(I _p ', U _p ') is used to fit I _pi and U _pi in the n sets of calibration data based on the least squares method, where I _p ' is the fitted current, and U _p ' is the fitting feedback voltage;

The processor module controls the adjustable working power supply to output a DC adjustable power supply voltage _US ', the adjustable power supply voltage _US ' is the input voltage of the input interface group of the relay control circuit, and the output interface of the relay control circuit The output voltage of the group is both U _S '; the adjustable power supply voltage U _S ' is the target voltage U _S0 ;

The current sensor converts the current I _f of the main test loop into a real-time feedback voltage U _f and sends it back to the processor module, where the real-time feedback voltage U _f is the target feedback voltage U _f0 ;

Substitute the target feedback voltage U _f0 into the correction function curve f(I _p ', U _p ') as the fitting feedback voltage U _p ' to obtain the corresponding fitting current, and the corresponding fitting The current is the target current I _f0 ;

The processor module obtains a set of target data, and the target data is {U _So , U _fo , I _fo }.

In an optional embodiment, the method for testing the DC resistance of the capacitor discharge coil further includes a discharging step, the discharging step is performed after the test calculation step, and the discharging step includes:

Discharge control step: the processor module controls the discharge switch on the discharge branch of the relay control circuit to close to form a discharge main loop, and the discharge branch includes a discharge switch and a discharge resistor.

Correspondingly, the present invention also provides a device for testing the DC resistance of a capacitor discharge coil, which is used to implement the method for testing the DC resistance of a capacitor discharge coil described in any one of the above.

To sum up, the present invention provides a method and equipment for testing the DC resistance of a capacitor discharge coil. By applying an adjustable DC voltage to both ends of the discharge coil under test, the current sensor is used to realize the selection of the tested branch without disconnecting the wire. And through the processor module and the corresponding relay control circuit, the fast and accurate measurement of the mA-level small current and the safe discharge function are realized, so as to obtain the DC resistance of the discharge coil of the high-voltage parallel capacitor, which has good implementation convenience.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 shows a schematic structural diagram of a capacitor discharge coil DC resistance testing device according to an embodiment of the present invention;

FIG. 2 shows a schematic structural diagram of a power supply circuit according to an embodiment of the present invention;

Figure 3 shows a schematic diagram of the processor structure of the STM32F103xx;

4 shows a schematic flowchart of a method for testing the DC resistance of a capacitor discharge coil according to an embodiment of the present invention;

5 shows a schematic structural diagram of a correction circuit for measuring the DC resistance of a capacitor discharge coil according to an embodiment of the present invention;

6 shows a schematic structural diagram of a measurement circuit for measuring the DC resistance of a capacitor discharge coil according to an embodiment of the present invention;

FIG. 7 shows a schematic diagram of the circuit structure of the device for measuring the DC resistance of the discharge coil of the capacitor according to the embodiment of the present invention when the device is discharged.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Before describing the method for testing the DC resistance of the capacitor discharge coil involved in the present invention, in order to facilitate understanding, the embodiment of the present invention first provides one of the capacitor discharge coil DC resistance testing equipment among the capacitor discharge coil DC resistance testing equipment. Capacitor Discharge Coil DC Resistance Test Equipment Describes the capacitor discharge coil DC resistance test method of the present invention.

Capacitor discharge coil DC resistance test equipment

FIG. 1 shows a schematic structural diagram of a device for testing the DC resistance of a capacitor discharge coil according to an embodiment of the present invention.

Specifically, an embodiment of the present invention provides a DC resistance testing device for a capacitor discharge coil, including a power supply circuit, peripheral equipment, an adjustable working power supply, a current sensor, a processor module and a relay control circuit.

relay control circuit

In the embodiment of the present invention, the relay control circuit includes an input interface group, an output interface group, a test branch, several correction branches and a discharge branch.

Specifically, the input interface group includes a first input interface and a second input interface, and the output interface group includes a first output interface and a second output interface. Since the circuit wiring generally includes a positive pole and a negative pole (which can be understood as a ground pole), the input interface group and the output interface group respectively have two interfaces. In the embodiment of the present invention, the first input interface can be understood as the positive pole The input interface, the first output interface can be understood as a positive output interface; and the second input interface and the second output interface can be understood as a ground wire, correspondingly, the second input interface and the second output interface are directly connected to form a ground wire. In this embodiment, the first input interface, the second input interface, the first output interface, and the second output interface are all connected to devices or modules outside the relay control circuit. For the entire circuit in which the relay control circuit actually works , by connecting different branches between the first input interface and the first output interface or between the second input interface and the second output interface, different circuit effects can be achieved. The actual running circuit between the input interface group and the output interface group is the main circuit of the relay control circuit.

Specifically, in this embodiment of the present invention, any correction branch among the several correction branches and the test branch are connected in parallel between the first input interface and the first output interface, that is, in the A plurality of parallel branches are arranged between the first input interface and the first output interface, and the plurality of parallel branches include several correction branches and one test branch.

Specifically, the test branch includes a test switch.

Specifically, any one of the several correction branches includes a correction switch and a correction resistor arranged in series, and the resistance values of the correction resistors of different correction branches of the several correction branches are different.

The calibration switches in the several calibration branches and the test switches in the test branches respectively have a switch control terminal and a switch drive terminal.

Through the above setting form, when it needs to be applied to a certain branch or combined application of multiple branches, it is only necessary to close the switch on the corresponding branch; since the switch adopts the signal control method, the processor module can pass the corresponding The type of signal controls the switches in each branch respectively. In actual operation, the purpose of changing the circuit loop can be realized without controlling the change of the circuit structure through physical operation, so as to realize various circuit functions and have good operation convenience. .

Specifically, since the DC resistance testing device of the capacitor discharge coil of the embodiment of the present invention needs to be used for the actual measurement of the high-voltage parallel capacitor device, in order to ensure the safety of use, the relay control circuit of the embodiment of the present invention further includes a discharge branch; the discharge Both ends of the branch are respectively connected between the first output interface and the second output interface; the discharge branch includes a discharge switch and a discharge resistor arranged in series; the discharge switch of the discharge branch has a switch control terminal and a switch drive end.

Similar to the correction branch and the test branch, the discharge switch is controlled by the processor module, and the timing of the discharge branch being connected to the circuit loop can be controlled, the discharge is fast, the operation is convenient, and it has good practicability and safety.

Adjustable working power

Specifically, the adjustable working power supply has a voltage regulation output end and a voltage regulation control end, and the voltage regulation output end is connected to the input interface group; it should be noted that the voltage regulation output end actually has a positive output end Corresponding to a negative output terminal (ground terminal), the positive output terminal and the negative output terminal of the voltage regulating output terminal are respectively connected with the first input interface and the second input interface of the relay control circuit.

The voltage regulation control terminal is mainly for the adjustable working power supply, which can output the corresponding output voltage according to the external voltage regulation signal.

In the embodiment of the present invention, the adjustable DC power supply converts 220V AC mains into DC output, and the voltage output range is 0V-50V.

current sensor

The current sensor has a current signal output terminal and a test terminal. The test terminal is used to obtain the current value of the target circuit, and the current signal output terminal is used to output the obtained current value of the target circuit; specifically, the current value of the target circuit is output to the processor module in the form of a voltage signal , the processor module converts the voltage signal into a current value according to its built-in data correspondence corresponding to a specific current sensor.

For ease of operation, the current sensor in the embodiment of the present invention selects an open-type Hall current sensor, the model is HKCT100-5, and the diameter is 40 mm. In the specific implementation, the current sensor only needs to be clamped on the loop of the target circuit, the operation is convenient, and the utility model has good practicability.

power supply circuit

FIG. 2 shows a schematic structural diagram of a power supply circuit according to an embodiment of the present invention. The power supply circuit has a power supply input end and a power supply output end, and the power supply output ends are respectively connected with components or circuits that need power supply. In specific use, the DC resistance testing device of the capacitor discharge coil of the embodiment of the present invention is generally directly connected to the commercial power for operation. Therefore, the power supply input terminal is used to connect to the commercial power, and the power supply circuit converts the commercial power into a specific voltage for output. Specifically, according to the selected component model, the specific required power supply circuit structure will also be changed accordingly. For various common component models in the prior art, optionally, the power supply circuit includes a direct connection circuit, a first conversion circuit and a second conversion circuit; the number of the power supply output terminals is multiple.

It should be noted that the power supply circuit in the embodiment of the present invention is directly powered by commercial power (220V alternating current). Therefore, the following content about voltage conversion is mainly implemented for commercial power.

Direct connection circuit: the input end of the direct connection circuit is connected to the power supply input end, the voltage of the output end of the direct connection circuit is the same as the voltage of the input end of the direct connection circuit, and the output end of the direct connection circuit is the same as the voltage of the input end of the direct connection circuit. One of the plurality of power supply output terminals is electrically connected; the function of the direct connection circuit is to directly output commercial power. In the embodiment of the present invention, the direct connection circuit can be used for power supply of the adjustable working power supply.

The first conversion circuit: the input terminal of the first conversion circuit is connected to the power supply input terminal, the output terminal voltage of the first conversion circuit is DC 12V, and the output terminal of the first conversion circuit is connected to a plurality of the One of the power supply output terminals is electrically connected; specifically, the implementation structure of the first conversion circuit can refer to the schematic structural diagram of the first conversion circuit shown in FIG. 2 of the accompanying drawings, wherein J1 is a 220 AC input interface, That is, the power supply input terminal; F1 is the insurance; C1 is the safety capacitor, which is used to protect the human body, so that the human body will not be affected by the motor after the power is cut off and contacting the circuit; R1 is the varistor, which will clamp after overvoltage voltage, so that the circuit voltage will not exceed the allowable threshold value of the varistor; T1 is a transformer, which is used to step down the 220V AC to the required 12V voltage; D1 to D4 are diodes of type IN4007, used to form a rectifier bridge, so that The AC 12V voltage is converted into a DC 12V voltage; C2 and C3 are filter capacitors and voltage regulator capacitors respectively. Through the setting of the first conversion circuit, the power supply circuit can output 12V DC voltage. In the embodiment of the present invention, the first conversion circuit may be used to supply power to the switch drive terminals of various control switches in the relay control circuit.

Second conversion circuit: the input terminal of the second conversion circuit is connected to the power supply input terminal, the output terminal voltage of the second conversion circuit is DC 5V, and the output terminal of the second conversion circuit is connected to a plurality of the One of the power supply output ends is electrically connected. In a specific implementation, the structure of the second conversion circuit may be similar to that of the first conversion circuit, and it is only necessary to replace the transformer model. In this embodiment of the present invention, the second conversion circuit may be used to supply power to the processor module.

In specific implementation, the first conversion circuit and the second conversion circuit are mainly used for power supply of peripheral devices and processor modules, and may be used according to actual conditions in specific implementation.

In the structure shown in FIG. 1 of the accompanying drawings, since the specific power supply situation of the power supply circuit needs to be confirmed according to the actual setting form, therefore, FIG. The power supply of the device or circuit needs to be adapted according to the actual implementation.

peripheral equipment

Specifically, since the embodiments of the present invention involve different job contents required by the processor module in different steps, in order to facilitate the control of the processor module, it is generally necessary to add a display device for displaying the contents of the processor module and for processing A control device that is controlled by the controller module.

Specifically, the control device may be a controller, and the plurality of peripheral devices include a controller; the processor module has a control receiving end connected to the controller. In specific implementation, the controller may select peripheral input devices such as buttons, knobs, keyboards, and mice.

Specifically, the plurality of peripheral devices include a display screen; the processor module has a display output terminal, and the display output terminal is connected to the display screen.

processor module

The processor module has a voltage regulation output end, a current signal receiving end, a test switch end, several calibration switch ends and a discharge switch end; the voltage regulation output end is connected to the voltage regulation control end, and the current signal receiving end The terminal is connected to the current signal output terminal; the test switch terminal is connected to the control terminal of the test switch, and the several correction switch terminals are respectively connected to the control terminals of the correction switches of the several correction branches; The discharge switch terminal is connected to the control terminal of the discharge switch.

Specifically, the processor module plays the roles of data reception, circuit control, and signal output.

Figure 3 shows a schematic diagram of the processor structure of the STM32F103xx. In specific implementation, the processor module can be based on STM32F103xx series processors. STM32F103xx uses a high-performance ARM Cortex-M3 32-bit RISC core; specifically, the processor includes ADC (Analog-to-Digital Converter, analog-to-digital converter), general-purpose 16-bit timer and PWM timer and communication interface; Generally, the communication interface includes an I2C interface, an SPI interface, a USART interface, a USB interface and a CAN interface (the above-mentioned communication interfaces are all interfaces of a specific protocol).

Specifically, the ADC interface can be used to connect with the current sensor to obtain the analog signal fed back by the current sensor; the GPIO interface (general-purpose input output interface) can be used to connect with the switch control terminal of the switch of each branch to control the access of each branch to the overall loop; the SPI interface can be used to connect with the voltage regulation control terminal of the adjustable working power supply to realize the control of the output voltage of the adjustable working power supply by the processor module; Interfaces such as an interface, a USART interface, a USB interface, and a CAN interface are connected, and the embodiments of the present invention will not be described one by one.

In the specific implementation, since the relay control circuit has built-in correction branch, test branch and discharge branch, the control of the access of different branches to the circuit loop can be realized through the signal control of the processor module, so that the present invention can be quickly realized The method for testing the DC resistance of the capacitor discharge coil of the embodiment is convenient in practical application and has good practicability.

Correspondingly, an embodiment of the present invention provides a method for testing the DC resistance of a capacitor discharge coil, which will be described below with reference to the device for testing the DC resistance of a capacitor discharge coil provided by the embodiment of the present invention.

Test method for DC resistance of capacitor discharge coil

FIG. 4 shows a schematic flowchart of a method for testing the DC resistance of a capacitor discharge coil according to an embodiment of the present invention. The method for testing the DC resistance of a capacitor discharge coil according to an embodiment of the present invention includes:

S101: Calibrate the current sensor and obtain the data sheet of the current sensor:

The current sensor transmits its data through an analog signal (voltage signal) during operation. After receiving the analog signal, the processor module converts it into a digital signal and converts it according to the preset correspondence (correspondence between the voltage signal and the current value). It is converted into a current value; since each current sensor has individual differences, the preset corresponding relationship provided by the manufacturer is not completely accurate. Therefore, the current sensor needs to be calibrated.

Specifically, the purpose of calibrating the current sensor is to find out the corresponding calibration current according to the calibration voltage of the current sensor. This step may not be required if the current sensor has been calibrated for a short period of time before use.

It should be noted that, in the specific implementation, to complete the calibration of the current sensor, a large amount of data needs to be tested, and the embodiment of the present invention only needs to obtain several (a small amount) of accurate data corresponding to the specific application scenarios required. , that is, to obtain several (a small amount) of correction voltages and their corresponding correction currents.

Specifically, the data table generating method includes:

S201: Correction wiring steps:

In the embodiment of the present invention, in step S101, it is first necessary to wire the capacitor discharge coil DC resistance testing device. Specifically, the first output interface and the second output interface of the output interface group of the relay control circuit are short-circuited to form a closed calibration main loop, and the current sensor is clamped on the calibration main loop; the current sensor is used to obtain all Correct the current of the main circuit as described above. After wiring, the specific schematic diagram of the circuit can refer to the schematic structural diagram of the correction circuit shown in FIG. 5 .

S202: Correction control steps:

The processor module controls the correction switches on the i-th correction branch of the n-way correction branches of the relay control circuit to be closed, and the correction switches on the remaining correction branches in the n-way correction branches are kept open, and the i-th correction branch is kept open. The ith correction branch is connected to the correction main circuit, and the i-th correction branch includes a correction resistor R _pi and a corresponding correction switch; specifically, the acquisition circuit of each group of correction data can be simplified as shown in FIG. 5 . the circuit structure shown.

It should be noted that the calibration resistance R _pi is known; in the embodiment of the present invention, the number of calibration branches connected to the calibration main circuit is one each time, therefore, the resistance value on the calibration main circuit is equal to the connection Correct the resistance value of the correction resistor on the correction branch of the main circuit. Specifically, the resistance values of the correction resistors between each group of correction branches are different. In the embodiment of the present invention, considering the resistance value of the actual discharge coil, the resistance value range of the correction resistor may be 1kΩ-5kΩ.

Specifically, the number of correction branches is represented by n, i=1, 2, ···, n. In the embodiment of the present invention, n=5, i=1, 2, 3, 4, and 5.

Specifically, the processor module enables the adjustable working power supply to output an adjustable power supply voltage U _s to the input interface group of the relay control circuit; in the embodiment of the present invention, U _s =48V. It should be noted that the adjustable power supply voltage U _s is only used for the output voltage of the adjustable working power supply, and U _s is not a constant value, and can be adjusted according to requirements in the specific implementation.

In the embodiment of the present invention, the resistance values of the calibration resistors of each set of calibration branches are R _p1 =1kΩ, R _p2 =2kΩ, R _p3 =3kΩ, R _p4 =4kΩ, R _p5 =5kΩ.

S203: Correction data acquisition steps:

所述可调电源电压

为所述继电器控制电路的输入接口组的输入电压，所述校正电阻R_pi两端电压为

The processor module controls the adjustable power supply voltage of the adjustable working power supply output DC

The adjustable supply voltage

is the input voltage of the input interface group of the relay control circuit, and the voltage across the correction resistor R _pi is

S204: Correction calculation steps:

得到第i组校正数据{U_pi,I_pi,R_pi}。The processor module calculates the correction current of the i-th correction branch

Obtain the i-th set of correction data {U _pi , I _pi , R _pi }.

The calibration wiring step, the calibration control step, the calibration data acquisition step, and the calibration calculation step are repeatedly performed to obtain n sets of calibration data.

(本发明实施例以48V为例)至继电器控制电路的输入接口组，然后处理器模块同步接收基于所述电流传感器发送的对应于所述第i路校正支路的放电线圈两端的校正电压U_pi；然后，处理器模块计算第i路校正支路的校正电流

通过以上实施方式，可得到若干组(本发明实施例为五组)精确的校正电压U_pi和校正电流I_pi的对应关系，从而处理器模块可以通过电流传感器所反馈的校正电压U_pi找到精确的对应校正电流I_pi。In S101, when starting the calibration, the processor module first closes the calibration switch of the i-th calibration branch, so that the i-th calibration branch is connected to the main circuit; then the processor module drives the adjustable working power supply to output the adjustable power supply voltage

(The embodiment of the present invention takes 48V as an example) to the input interface group of the relay control circuit, and then the processor module synchronously receives the correction voltage U corresponding to the two ends of the discharge coil of the i-th correction branch sent based on the current sensor. _pi ; then, the processor module calculates the correction current of the i-th correction branch

Through the above implementations, several groups (five groups in the embodiment of the present invention) can be obtained to obtain accurate correspondences between the correction voltage U _pi and the correction current I _pi , so that the processor module can find the exact correct voltage U pi through the correction voltage U _pi fed back by the current sensor. The corresponding correction current I _pi .

Specifically, the data measured in the embodiment of the present invention are shown in the following table:

In a specific implementation, all the correction data are aggregated to form a data table, the data table includes n groups of correction data {U _pi , I _pi , R _pi }, i=1, 2,...,n, where U _pi is the i-th Correction voltage of the group of correction data, I _pi is the correction current of the i-th group of correction data, R _pi is the correction resistance value of the i-th group of correction data, where i=1,2,...,n.

Through this S101, the correction of the corresponding relationship of several data in the current sensor can be completed, and a data table can be obtained; the data table is synchronously updated to the processor module, so that the processor module can accurately obtain the voltage signal fed back by the current sensor according to the current sensor. The current magnitude data that the current sensor actually needs to transmit (correction current I _pi ).

S102: Test wiring steps;

Specifically, after the data table is acquired in step S101, it is necessary to connect the capacitor discharge coil DC resistance test equipment to the working circuit where the discharge coil is located. Correspondingly, it is necessary to perform new wiring for the capacitor discharge coil DC resistance test equipment .

Connect the first output interface and the second output interface of the output interface group of the relay control circuit to the two ends of the discharge coil respectively, and clamp the current sensor on the branch where the measured discharge coil is located; specifically, Figure 6 shows A schematic diagram of the circuit structure for measuring the DC resistance of the capacitor discharge coil according to the embodiment of the present invention is shown. The working circuit in which the discharge coil is located mainly includes a capacitor device (represented by a capacitor symbol in FIG. 6 ) and a corresponding discharge coil, and the discharge coil is connected in parallel with the capacitor device.

S103: test control step;

The processor module controls the test switch on the test branch of the relay control circuit to close to form a test main circuit, and the test branch includes the test switch;

After the step S103 , a schematic diagram of the circuit structure of the device for testing the DC resistance of the capacitor discharge coil according to the embodiment of the present invention is shown in FIG. 6 .

S104: Steps for acquiring target data:

Specifically, the acquisition of the target data in the embodiment of the present invention has two modes, namely the precise mode and the fast mode.

Specifically, in the precise mode, the processor module controls the adjustable working power supply to output a DC adjustable power supply voltage U _S , the adjustable power supply voltage U _S is the input voltage of the input interface group of the relay control circuit, the The output voltage of the output interface group of the relay control circuit is the same as _US ; in the embodiment of the present invention, the boost stop condition is that the adjustable power supply voltage US reaches the upper limit of the output voltage of _50V or the upper limit of the output current of 100mA. When the boost stop condition is reached, the adjustable supply voltage US can be _obtained .

The current sensor converts the current I _f of the branch where the discharge coil is located into a real-time feedback voltage U _f and sends it back to the processor module;

The processor module adjusts the adjustable power supply voltage U _S according to the real-time feedback voltage U _f until the real-time feedback voltage U _f is equal to the correction voltage U _pk of the kth group of correction data in the data table; at this time, the The adjustable power supply voltage U _S is the target voltage U _S0 , the real-time feedback voltage U _f is the target feedback voltage U _f0 , and in the kth group of correction data, the correction current I _pk corresponding to the correction voltage U _pk is target current I _f0 ;

The processor module obtains a set of target data, and the target data is {U _S0 , U _f0 , I _f0 }.

Specifically, in the fast mode, a calibration function curve f(I _p ', U _p ') is used to fit I _pi and U _pi in the n sets of calibration data based on the least squares method, and I _p ' is the fitting current , U _p ' is the fitting feedback voltage;

The processor module controls the adjustable working power supply to output a DC adjustable power supply voltage _US ', the adjustable power supply voltage _US ' is the input voltage of the input interface group of the relay control circuit, and the output interface of the relay control circuit The output voltage of the group is both U _S '; the adjustable power supply voltage U _S ' is the target voltage U _S0 ;

The current sensor converts the current I _f of the branch where the discharge coil is located into a real-time feedback voltage U _f and sends it back to the processor module, where the real-time feedback voltage U _f is the target feedback voltage U _f0 ;

Substitute the target feedback voltage U _f0 into the correction function curve f(I _p ', U _p ') as the fitting feedback voltage U _p ' to obtain the corresponding fitting current, and the corresponding fitting The current is the target current I _f0 ;

The processor module obtains a set of target data, and the target data is {U _So , U _fo , I _fo }.

In step S104, the ultimate purpose is to obtain a set of target data {U _So , U _fo , I _fo }.

S105: calculation step;

Specifically, the processor module calculates the DC resistance of the discharge coil

S106: discharge step;

After step S105 is completed, the capacitor needs to be fully discharged.

The discharging step includes:

S301: Discharge control steps:

The processor module controls the discharge switch on the discharge branch of the relay control circuit to close, and simultaneously opens the test switch on the test branch to form a discharge main circuit. The discharge branch includes a discharge switch and a discharge resistor. The residual charge on the capacitor can be discharged through the discharge main circuit. In the embodiment of the present invention, the discharge starting condition is that the adjustable power supply voltage US drops to _0V .

Specifically, the schematic diagram of the discharge circuit structure of the capacitor discharge coil DC resistance test equipment is shown in FIG. 7 .

To sum up, the embodiments of the present invention provide a method and device for testing the DC resistance of a capacitor discharge coil. Through the access control of the processor module to different branches and different wiring methods, the correction of the current sensor and the DC resistance of the capacitor discharge coil can be realized. The measurement of resistance and the discharge function of the high-voltage parallel capacitor device have good operation convenience; the current sensor adopts a current clamp structure, and the DC resistance of the discharge coil can be measured without removing the discharge coil, which is easy to use and has good practicability .

The method and equipment for testing the DC resistance of a capacitor discharge coil provided by the embodiments of the present invention have been described above in detail. The principles and implementations of the present invention are described with specific examples in this paper. The descriptions of the above embodiments are only used for Help to understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification It should not be construed as a limitation of the present invention.

Claims (4)

1. A method for testing the DC resistance of a capacitor discharge coil, used for the detection of the DC resistance of a discharge coil in a high-voltage parallel capacitor device, the high-voltage parallel capacitor device comprising a discharge coil arranged in parallel on the capacitor device; It is characterized in that it includes: Test wiring step: connect the first output interface and the second output interface of the output interface group of the relay control circuit to both ends of the branch where the discharge coil is located to form a test main circuit, and clamp the current sensor on the test main circuit; Test control step: the processor module controls the test switch on the test branch of the relay control circuit to close, the test branch is connected to the test main circuit, and the test branch includes a test switch; The target data acquisition step: in the precise mode, the processor module controls the adjustable working power supply to output a DC adjustable power supply voltage _US , where the adjustable power supply voltage US is the input voltage of the input interface _group of the relay control circuit, The output voltage of the output interface group of the relay control circuit is the same as _US ; The current sensor converts the current I _f of the main test loop into a real-time feedback voltage U _f and sends it back to the processor module; The processor module adjusts the adjustable power supply voltage U _S according to the real-time feedback voltage U _f until the real-time feedback voltage U _f is equal to the correction voltage U _pk of the kth group of correction data in the data table; at this time, the The adjustable power supply voltage U _S is the target voltage U _S0 , the real-time feedback voltage U _f is the target feedback voltage U _f0 , and in the kth group of correction data, the correction current I _pk corresponding to the correction voltage U _pk is target current I _f0 ; The processor module obtains a set of target data, and the target data is {U _S0 , U _f0 , I _f0 }; Test calculation step: the processor module calculates the DC resistance of the discharge coil

The data table includes n groups of correction data {U _pi , I _pi , R _pi }, i=1,2,...,n, where U _pi is the correction voltage of the i-th group of correction data, and I _pi is the i-th Correction current of the group of correction data, R _pi is the correction resistance value of the i-th group of correction data, k∈{1,2,…,n}; Each set of the calibration data represents a calibration current obtained by applying a corresponding calibration voltage across a calibration resistor and through calculation, the calibration voltage and the calibration resistor are confirmed values, and the calibration current value reflects the current sensor the actual current size; The data table generation method includes: Calibration wiring step: short-circuit the first output interface and the second output interface of the output interface group of the relay control circuit to form a closed calibration main circuit, and clamp the current sensor on the calibration main circuit; The correction control step: the processor module controls the correction switch on the i-th correction branch in the n correction branches of the relay control circuit to close, and the correction switches on the other correction branches in the n correction branches are kept open, The i-th correction branch is connected to the correction main circuit, and the i-th correction branch includes a correction resistor R _pi and a corresponding correction switch; Correction data acquisition steps: The processor module controls the adjustable power supply voltage of the adjustable working power supply to output DC

The adjustable supply voltage

is the input voltage of the input interface group of the relay control circuit, and the voltage across the correction resistor R _pi is

The current sensor converts the correction current I _pi of the correction main circuit into a real-time feedback correction voltage U _pi and sends it back to the processor module; Correction calculation steps: the processor module calculates the correction current of the main circuit for correction

Obtain the i-th set of correction data {U _pi , I _pi , R _pi }; The calibration wiring step, the calibration control step, the calibration data acquisition step, and the calibration calculation step are repeatedly performed to obtain n sets of calibration data. 2. The method for testing the DC resistance of a capacitor discharge coil as claimed in claim 1, wherein the target data acquisition step further comprises: In the fast mode, a calibration function curve f(I _p ', U _p ') is used to fit I _pi and U _pi in the n sets of calibration data based on the least squares method, where I _p ' is the fitted current, and U _p ' is the fitting feedback voltage; The processor module controls the adjustable working power supply to output a DC adjustable power supply voltage _US ', the adjustable power supply voltage _US ' is the input voltage of the input interface group of the relay control circuit, and the output interface of the relay control circuit The output voltage of the group is both U _S '; the adjustable power supply voltage U _S ' is the target voltage U _S0 ; The current sensor converts the current I _f of the main test loop into a real-time feedback voltage U _f and sends it back to the processor module, where the real-time feedback voltage U _f is the target feedback voltage U _f0 ; Substitute the target feedback voltage U _f0 into the correction function curve f(I _p ', U _p ') as the fitting feedback voltage U _p ' to obtain the corresponding fitting current, and the corresponding fitting The current is the target current I _f0 ; The processor module obtains a set of target data, and the target data is {U _So , U _fo , I _fo }. 3. The method for testing the DC resistance of a capacitor discharge coil according to claim 1, wherein the method for testing the DC resistance of a capacitor discharge coil further comprises a discharging step, and the discharging step is performed after the test calculation step, and the The discharge steps include: Discharge control step: the processor module controls the discharge switch on the discharge branch of the relay control circuit to close to form a discharge main loop, and the discharge branch includes a discharge switch and a discharge resistor. 4 . A device for testing the DC resistance of a capacitor discharge coil, characterized in that it is used to implement the method for testing the DC resistance of a capacitor discharge coil according to any one of claims 1 to 3 .

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