A kind of charging method of capacitor leakage tester and device
Technical field
The present invention relates to a kind of capacitance measuring tester, particularly a kind of charging method of capacitor leakage tester and device.
Background technology
In various electronics and machinery industry, various products all contain capacity cell, as when carrying out the test of some operation test case such as electric capacity, need to test the electric leakage of electric capacity.The detection of general capacitor leakage tester comprises three phases: measured capacitance is charged, the electric leakage of measured capacitance is tested, measured capacitance is discharged.For discharge regime, capacitor leakage tester in the past all is to discharge with mechanical switch, and the defective of this circuit is to utilize the mechanical switch discharge fully, can produce instant high-voltage and large electric current in the discharge starting stage, thereby cause the arcing phenomenon of mechanical shaking and high-voltage great-current, when electric capacity has larger voltage, the discharge meeting causes very large interference to the digital control system of various instruments, cause deadlock, reset, even more serious consequence, for the digital implementation of accurate measurement or control, the perhaps instrument of demand continuous working, this consequence is very unfavorable to the corresponding course of work.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of safe-discharge method and apparatus to high voltage electric capacity, and the instant high-voltage that its starting stage that can prevent from discharging produces and large electric current cause the arcing phenomenon of mechanical shaking and high-voltage great-current.
The charging method of a kind of capacitor leakage tester of the present invention, it comprises the steps:
1) discharge selector switch, electron discharge circuit, mechanical discharge circuit and the measured capacitance that a microprocessor is controlled is set, the discharge selector switch of described microprocessor control is connected to electron discharge circuit or mechanical discharge circuit with measured capacitance;
2) voltage of measured capacitance is judged;
3) when the voltage of measured capacitance was higher than the setting reference value, the discharge selector switch of microprocessor control switched to the electron discharge circuit with measured capacitance and discharges;
4) when the voltage of measured capacitance is less than or equal to the setting reference value of described comparer, microprocessor controlled discharge selector switch switches to mechanical discharge circuit with measured capacitance and discharges;
Described step 3) and step 4) between without sequencing.
One comparer being set to step 2) voltage of described measured capacitance judges, when the voltage of measured capacitance is higher than a setting reference value, the output state of comparer changes, and produces the interrupt notification microprocessor selector switch of will discharging and switches to the electron discharge circuit measured capacitance is discharged; Be less than or equal to one when setting reference value when the voltage of measured capacitance, the output state of comparer changes, and produces the interrupt notification microprocessor selector switch of will discharging and switches to mechanical discharge circuit measured capacitance is discharged.The mode that described discharge selector switch is switched is the switch control end of output one discharge signal to corresponding discharge circuit.
Described electron discharge circuit arranges high-power FET serial connection high-power resistance described measured capacitance is carried out electron discharge.The machinery discharge circuit arranges relay serial connection high-power resistance described measured capacitance is carried out the machinery discharge.
The electric discharge device of a kind of capacitor leakage tester of the present invention, comprise discharge selector switch, electron discharge circuit, mechanical discharge circuit, voltage comparator and the measured capacitance of microprocessor control, the two ends of described measured capacitance are connected to described electron discharge circuit and mechanical discharge circuit; The output terminal of described voltage comparator connects microprocessor, and each connects the end of oppisite phase of voltage comparator the two ends of measured capacitance through a resistance.
Described electron discharge circuit comprises high-power FET, high-power resistance, diode, the first discharge signal control end and a resistance, described discharge signal output terminal is connected to the grid of described high-power FET through described resistance, the positive voltage terminal of described measured capacitance is connected to the drain electrode of high-power FET successively through described diode, high-power resistance, the source ground of high-power FET, the anode of described diode connect an end of electric capacity.
Described mechanical discharge circuit comprises relay, the second discharge signal control end and discharge switch, described discharge switch comprises a triode, the collector connection relay of triode, grounded emitter, the base stage of the second discharge signal control end connecting triode, the fixed contact of described relay is connected measured capacitance with a moving contact.
The invention has the beneficial effects as follows: utilize the electronic switch discharge, can not produce instant high-voltage and large electric current in the discharge starting stage, stop the arcing phenomenon of mechanical shaking and high-voltage great-current to occur, do not disturb the digital control system of various instruments and cause deadlock, the consequence such as reset, and carry out carrying out again the machinery discharge behind the electron discharge, can reach the purpose of thorough discharge.
Below in conjunction with accompanying drawing and embodiment, the present invention is described in further detail:
Description of drawings
Fig. 1 is the circuit theory diagrams that the present invention carries out electron discharge;
Fig. 2 is the circuit theory diagrams that the present invention carries out the machinery discharge.
Embodiment
Referring to Fig. 1 and Fig. 2, the charging method of a kind of capacitor leakage tester of the present invention, it comprises the steps:
1) discharge selector switch, electron discharge circuit, mechanical discharge circuit and the measured capacitance that a microprocessor is controlled is set, the discharge selector switch of described microprocessor control is connected to electron discharge circuit or mechanical discharge circuit with measured capacitance;
2) voltage of measured capacitance Cx is judged;
3) when the voltage of measured capacitance was higher than the reference value of described comparer VREF end setting, the discharge selector switch end CTL_1 of microprocessor control and CTL_2 switched to the electron discharge circuit with measured capacitance and discharge;
4) when the voltage of measured capacitance was less than or equal to the setting reference value of described comparer VREF end, microprocessor controlled discharge selector switch CTL_1 and CTL_2 switched to mechanical discharge circuit with measured capacitance and discharge;
Described step 3) and step 4) between without sequencing.
One comparer U1-A being set to step 2) magnitude of voltage of described measured capacitance Cx judges, when the voltage of measured capacitance Cx is higher than comparer VREF end setting reference value, the output state of comparer changes, produce the interrupt notification microprocessor selector switch of will discharge and switch to the electron discharge circuit, namely CTL_1 holds output signal conducting Q10 and Q11 that measured capacitance Cx is discharged; When the voltage of measured capacitance Cx is less than or equal to VREF end setting reference value, the output state of comparer changes, produce the interrupt notification microprocessor selector switch of will discharge and switch to mechanical discharge circuit, namely CTL_2 holds output signal conducting Q1 that measured capacitance Cx is discharged.
Described electron discharge circuit arranges high-power FET Q10, Q11 serial connection high-power resistance R1, R2 described measured capacitance Cx is carried out electron discharge.The machinery discharge circuit arranges a relay K 1 serial connection high-power resistance described measured capacitance Cx is carried out the machinery discharge.
The electric discharge device of a kind of capacitor leakage tester of the present invention, comprise discharge selecting side CTL_1 and CTL_2, electron discharge circuit, mechanical discharge circuit, voltage comparator U1-A and the measured capacitance Cx of microprocessor control, the two ends of described measured capacitance Cx are connected to described electron discharge circuit and mechanical discharge circuit; The output terminal 1 of voltage comparator U1-A connects microprocessor, and in-phase end 3 connects a reference voltage end VREF, and each connects the end of oppisite phase 2 of voltage comparator the two ends of measured capacitance Cx through a resistance R 3, R5.
Described electron discharge circuit comprises high-power FET Q10 and Q11, high-power resistance R1 and R2, diode D1 and D2, the first discharge signal control end CTL_1 and a resistance R 4, described the first discharge signal control end CTL_1 is connected to the grid of described high-power FET Q10 and Q11 through resistance R 4, the positive voltage terminal of described measured capacitance Cx is connected to the drain electrode of Q10 and Q11 successively through described diode D1 and D2, high-power resistance R1 and R2, the source ground of Q10 and Q11, the anode of described diode D1 and D2 connects the end of nearly capacitor C x.
Described mechanical discharge circuit comprises relay K 1, the second discharge signal control end CTL_2 and discharge switch, described discharge switch comprises a triode Q1, the collector connection relay K1 of Q1, grounded emitter, the base stage of the second discharge signal control end CTL_2 connecting triode Q1, the fixed contact 3 of described relay K 1 is connected measured capacitance Cx with a moving contact 5.
More than invention is described only is most preferred embodiment of the present invention; not in order to limit the present invention; all modifications of doing on basis of the present invention, replacement or improvement realize identical break-make effect as changing the component type in the discharge switch, all fall within the scope of protection of the present invention.