CN211979022U - Isolation module for testing based on electric energy conversion system - Google Patents
Isolation module for testing based on electric energy conversion system Download PDFInfo
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- CN211979022U CN211979022U CN202020500191.9U CN202020500191U CN211979022U CN 211979022 U CN211979022 U CN 211979022U CN 202020500191 U CN202020500191 U CN 202020500191U CN 211979022 U CN211979022 U CN 211979022U
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Abstract
The utility model provides a test is with isolation module based on electric energy transform system, including voltage measurement unit, current measurement unit, PWM pulse measurement unit and power supply circuit, power supply circuit's input is connected with external power source, power supply circuit's output respectively with voltage measurement unit, current measurement unit, PWM pulse measurement unit is connected, voltage measurement unit, current measurement unit and PWM pulse measurement unit's input all is connected with the electric energy transform system, voltage measurement unit, current measurement unit and PWM pulse measurement unit's output all is connected with oscilloscope. The utility model provides a current electric energy transform system test equipment technical problem expensive, poor stability. The utility model has the advantages of simple circuit, reliable operation and high cost performance.
Description
Technical Field
The utility model relates to a technical field of electric energy transform especially indicates an isolation module is used in test based on electric energy transform system.
Background
With the development of distributed power generation, flexible power transmission technology and the like, a future power grid will be a power electronized power grid. For power electronic technology with the important theoretical and practical requirements, an experimental link is indispensable. The core of the power electronic technology, namely, electric energy conversion, is often faced with the problem of electric quantity measurement of different reference grounds in research and experimental teaching thereof, such as measurement of input signals and output electric quantity of different reference grounds in a rectifying circuit; the switch device isolates input signals and output electric quantity measurement of different reference grounds in the driving circuit and the like. In view of the different reference ground in the power conversion system, the power measurement generally needs to be isolated.
At present, there are 3 kinds of signal isolation test schemes, namely, a test scheme using an isolation type oscilloscope, a test scheme using a common oscilloscope + a differential probe and a common oscilloscope + an isolation module. The isolated oscilloscope is the best choice, but the cost is high, and particularly, the cost for students to experiment is more difficult to accept by matching with a plurality of sets of laboratories in colleges and universities; the method of the common oscilloscope plus the differential probe in the scheme 2 can reduce the cost, but the price of the differential probe is still expensive, and the differential probe is easy to damage in the using process of students; in the scheme of the 3 rd scheme, which is a common scheme of the oscilloscope and the isolation module, the isolation technology mainly adopts the following methods: transformer isolation, linear optical coupling isolation, operational amplifier isolation and the like, which can theoretically obtain a higher frequency band, but the cost increases with the increase of frequency, the number of isolated power supplies increases with the increase of the number of channels, and the high-frequency signal interference of the isolated power supplies can also cause the reduction of the system stability.
SUMMERY OF THE UTILITY MODEL
To the not enough that exists among the above-mentioned background art, the utility model provides an isolation module is used in test of electric energy transformation system has solved current electric energy transformation system test equipment high price, poor stability's technical problem.
The technical scheme of the utility model is realized like this:
the utility model provides an isolation module for test based on electric energy conversion system, includes voltage measuring unit, current measuring unit, PWM pulse measuring unit and power supply circuit, power supply circuit's input is connected with external power supply, power supply circuit's output is connected with voltage measuring unit, current measuring unit, PWM pulse measuring unit respectively, voltage measuring unit, current measuring unit and PWM pulse measuring unit's input all is connected with the electric energy conversion system, voltage measuring unit, current measuring unit and PWM pulse measuring unit's output all are connected with the oscilloscope.
And the oscilloscope is provided with a measuring probe which is respectively connected with the output end of the voltage measuring unit, the output end of the current measuring unit and the output end of the PWM pulse measuring unit.
The voltage measuring unit comprises a current limiting circuit, a Hall voltage sensor and a first signal conversion circuit; the input end of the current limiting circuit is the positive electrode of the input end of the voltage measuring unit, the input end of the current limiting circuit is connected with the electric energy conversion system, the output end of the current limiting circuit is connected with the positive electrode of the input end of the Hall voltage sensor, the negative electrode of the input end of the Hall voltage sensor is the negative electrode of the input end of the voltage measuring unit, and the negative electrode of the input end of the Hall voltage sensor is connected with the electric energy conversion system; the power supply end of the Hall voltage sensor is connected with the output end of the power supply circuit; the first signal conversion circuit is connected between the output end of the Hall voltage sensor and the output grounding end of the power supply circuit, the first signal conversion circuit is the output end of the voltage measurement unit, and the first signal conversion circuit is connected with the measurement probe.
The current measuring unit comprises a coil, a Hall current sensor and a second signal conversion circuit, the coil is connected with the electric energy conversion system, the coil is wound on the Hall current sensor, a power supply end of the Hall current sensor is connected with an output end of the power supply circuit, the second signal conversion circuit is connected between the output end of the Hall current sensor and an output grounding end of the power supply circuit, the second signal conversion circuit is an output end of the current measuring unit, and the second signal conversion circuit is connected with the measuring probe.
The PWM pulse measuring unit comprises a photoelectric isolation circuit and a phase adjusting circuit, the photoelectric isolation circuit is an input end of the PWM pulse measuring unit, the photoelectric isolation circuit is respectively connected with the electric energy conversion system, the photoelectric isolation circuit is connected with the phase adjusting circuit, the phase adjusting circuit is an output end of the PWM pulse measuring unit, and the phase adjusting circuit is connected with the measuring probe.
The power supply circuit comprises an AC/DC circuit and a DC/DC circuit, wherein the input end of the AC/DC circuit is connected with an external power supply, the output end of the AC/DC circuit is respectively connected with the DC/DC circuit, a Hall voltage sensor and a Hall current sensor, and the output end of the DC/DC circuit is connected with the power supply end of the PWM pulse measuring unit.
The electric energy conversion system is an inverter, a frequency converter, a rectifier, a switching power supply or an electronic load.
The beneficial effect that this technical scheme can produce:
(1) the utility model discloses in the voltage measurement of electric energy conversion system, use voltage measurement unit to a plurality of to be measured voltage isolation measurement that have different reference ground, realized the isolation measurement and the simultaneous measurement to the to be measured voltage of multiple voltage class;
(2) in the current measurement of the electric energy conversion system, the current measurement unit is used for carrying out isolated measurement on the current to be measured, so that the measurement on the current to be measured with various current grades is realized;
(3) in the electric quantity measurement of the electric energy conversion system, a PWM pulse measurement unit is used for carrying out isolation measurement on low-voltage high-frequency PWM pulses to be measured with different reference grounds;
(4) the simultaneous measurement of a common four-channel oscilloscope on multi-path electric quantity is met by arranging three voltage measuring units and one current measuring unit, for example, the simultaneous measurement of three-phase voltage and one-phase current in a three-phase inverter system is realized;
(5) the two PWM pulse measuring units meet the requirement of using a common four-channel oscilloscope to simultaneously measure the PWM pulses and the related electric quantity, for example, the two PWM pulses of an upper bridge arm and a lower bridge arm in a switching tube driving circuit and the related voltage or current are simultaneously measured;
(5) the utility model has the advantages of simple circuit, reliable operation and high cost performance.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a block diagram of the present invention;
fig. 2 is a schematic block diagram of a voltage measuring unit according to the present invention;
fig. 3 is a schematic block diagram of a current measuring unit according to the present invention;
fig. 4 is a schematic block diagram of a PWM pulse measurement unit according to the present invention;
fig. 5 is a schematic block diagram of the power supply circuit of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without any creative effort belong to the protection scope of the present invention.
As shown in FIG. 1, the embodiment of the utility model provides an isolation module is used in test based on electric energy transformation system, including voltage measurement unit, current measurement unit, PWM pulse measurement unit and power supply circuit, power supply circuit's input is connected with external power supply, and power supply circuit's output is connected with voltage measurement unit, current measurement unit, PWM pulse measurement unit respectively, and 220V's external power supply provides the power for voltage measurement unit, current measurement unit, PWM pulse measurement unit respectively after power supply circuit conversion. The input ends of the voltage measuring unit, the current measuring unit and the PWM pulse measuring unit are all connected with an electric energy conversion system, the electric energy conversion system is an inverter, a frequency converter, a rectifier, a switching power supply or an electronic load, and the output ends of the voltage measuring unit, the current measuring unit and the PWM pulse measuring unit are all connected with an oscilloscope. The voltage measuring unit converts the voltages to be measured with different reference grounds into signals which can be measured by a common oscilloscope and a conventional probe, and converts the voltages to be measured with various voltage amplitudes into signals which can be measured by the common oscilloscope and the conventional probe; the current to be measured of the current measuring unit is converted into a voltage signal which can be measured by a common oscilloscope and a conventional voltage probe, so that the current measurement of various current grades is realized; the PWM pulse measuring unit converts low-voltage high-frequency PWM pulses of different reference grounds into signals which can be measured by a common oscilloscope and a conventional probe. The voltage measuring units are three, and are used for simultaneously and separately measuring the multipath voltage by using a common four-channel oscilloscope, for example, the three-phase voltage in a three-phase inverter system is simultaneously measured. The two PWM pulse measuring units are used for simultaneously and separately measuring the multiple paths of PWM pulses by using a common oscilloscope, for example, two paths of PWM pulses of an upper bridge arm and a lower bridge arm in a driving circuit of a switching tube are simultaneously measured.
The oscilloscope is provided with the measuring probe which is a plurality of channel non-isolated measuring probes, and can simultaneously perform isolated measurement on a plurality of voltage signals, current signals or pulse signals. The measuring probe is respectively connected with the output end of the voltage measuring unit, the output end of the current measuring unit and the output end of the PWM pulse measuring unit.
As shown in fig. 2, the voltage measuring unit includes a current limiting circuit, a hall voltage sensor, and a first signal conversion circuit; the input end of the current limiting circuit is the positive electrode of the input end of the voltage measuring unit, the input end of the current limiting circuit is connected with the electric energy conversion system, the output end of the current limiting circuit is connected with the positive electrode of the input end of the Hall voltage sensor, the negative electrode of the input end of the Hall voltage sensor is the negative electrode of the input end of the voltage measuring unit, the negative electrode of the input end of the Hall voltage sensor is connected with the electric energy conversion system, and the Hall voltage sensor plays a role in current isolation and conversion; the power supply end of the Hall voltage sensor is connected with the output end of the power supply circuit, and the power supply circuit supplies power to the Hall voltage sensor; the first signal conversion circuit is connected between the output end of the Hall voltage sensor and the output grounding end of the power supply circuit, the first signal conversion circuit is the output end of the voltage measurement unit, and the first signal conversion circuit is connected with the measurement probe. The first signal conversion circuit comprises a resistor R4, one end of a resistor R4 is respectively connected with the output end of the Hall voltage sensor and the anode of the measuring probe, the other end of the resistor R4 is respectively connected with the cathode of the measuring probe and the grounding end of the voltage circuit, and the resistor R4 converts the current signal output by the Hall voltage sensor into a voltage signal.
The voltage measuring unit provides a range selection function through the current limiting circuit, three ranges of 0-1400V, 0-700V and 0-70V are provided, the corresponding range is selected according to the voltage amplitude of the voltage to be measured during measurement, and the low range is selected to obtain higher measurement precision under the condition that the voltage to be measured does not exceed the range. The current limiting circuit comprises a resistor R1, a resistor R2 and a resistor R3, wherein the resistor R1, the resistor R2 and the resistor R3 are connected in series; the other end of the resistor R3 is connected with the anode of the input end of the Hall voltage sensor; the end point of the resistor R1, the common end point of the resistor R1 and the resistor R2, and the common end point of the resistor R2 and the resistor R3 are all connected with the anode of the voltage to be measured in the electric energy conversion system, the three end points are respectively used for measuring three voltage ranges of 0-1400V, 0-700V and 0-70V, one end point is selected according to the amplitude of the voltage to be measured to be connected with the voltage to be measured, the cathode of the voltage to be measured in the electric energy conversion system is connected with the COMx (x =1,2, 3) end of the Hall voltage sensor, and COMx is the common end point of the three voltage ranges.
Aiming at the voltage measuring unit, the Hall voltage sensor adopts a closed-loop Hall voltage sensor, the transformation ratio is 10mA/25mA, and the internal resistance of the input end is 250 omega. According to the working principle of the hall voltage sensor, different current-limiting resistors are required to be used for implementation, in fig. 2, the resistor R1=87.5K Ω, the resistor R2=78.75K Ω, and the resistor R3=8.5K Ω, wherein the three resistor values are not nominal values, and need to be obtained through series-parallel connection of the nominal resistors, it is noted that the current flowing through the circuit in the maximum range (0-1400V) is 8mA, and the rated power of the resistor needs to meet the requirement when the resistor is selected; resistor R4=350 Ω, which also needs to be obtained by series-parallel connection of nominal resistors.
The transformation ratio of the Hall voltage sensor is 10mA/25mA, the internal resistance of the input end is 250 omega, the ratio of the current of the input end to the current of the output end is 10:25 according to the working principle of the Hall voltage sensor, and the following formula is as follows:
where Rin is the input terminal equivalent resistance, Rout is the resistance R4, Uin is the input voltage, and Uin is the output voltage signal. At a measuring range of 0-1400V, Rin = R1+ R2+ R3+250=175K Ω; at the measuring range of 0-700V, Rin = R2+ R3+250=87.5K omega; at a measuring range of 0-70V, Rin = R3+250=8.75K Ω. Substituting Rin with different ranges into the formula (1) to obtain: at a range of 0 to 1400V, Uin/Uout =200, at a range of 0 to 700V, Uin/Uout =100, and at a range of 0 to 70V, Uin/Uout = 10.
As shown in fig. 3, the current measuring unit includes a coil wound on the hall current sensor, and a second signal conversion circuit; the coil is wound on the Hall current sensor, the coil provides a range selection function, three tap ends and a common end COM4 are arranged on the coil, one of the tap ends and the common end COM4 is selected according to a range to form a loop, and the loop is connected in series with a current loop to be measured to measure current; the Hall current sensor plays a role in isolating and converting large current into small current; the power supply end of the Hall current sensor is connected with the output end of the power supply circuit to supply power to the Hall current sensor; the second signal conversion circuit is connected between the output end of the Hall current sensor and the output grounding end of the power supply circuit, the second signal conversion circuit is the output end of the current measuring unit, and the second signal circuit is connected with the measuring probe. The second signal conversion circuit comprises a resistor R5, one end of a resistor R5 is respectively connected with the output end of the Hall current sensor and the anode of the measuring probe, the other end of the resistor R5 is respectively connected with the cathode of the measuring probe and the grounding end of the voltage circuit, and the resistor R5 converts the current signal output by the Hall current sensor into a voltage signal.
For the current measuring unit, the Hall current sensor adopts a closed-loop Hall current sensor, the transformation ratio is 50A/50mA, and the resistance R5=100 Ω. The current measuring unit has three current measuring ranges of 0-5A, 0-10A and 0-25A, and the current measuring unit respectively corresponds to a coil wound on the Hall current sensor and has 10 turns, 5 turns and 2 turns. According to the working principle of the Hall current sensor, the ratio of the current passing through the Hall current sensor to the current at the output end is 1000:1, and the current passing through the Hall current sensor is equal to the current Iin to be measured multiplied by the number n of turns of a coil through which the Iin flows, so that the following formula is obtained:
where Iout is the output terminal current, Uout is the output voltage signal, and Rout is the resistor R5=100 Ω. Substituting n at different measuring ranges into the formula (2) and the formula (3) to obtain: at a range of 0-5A, n =10 turns, Uout/Iin =1V/1A, at a range of 0-10A, n =5 turns, Uout/Iin =1V/2A, at a range of 0-25A, n =2 turns, Uout/Iin = 1V/5A.
As shown in fig. 4, the PWM pulse measurement unit includes a photoelectric isolation circuit and a phase adjustment circuit, the photoelectric isolation circuit is an input terminal of the PWM pulse measurement unit, the photoelectric isolation circuit is respectively connected to the electric energy conversion system, the photoelectric isolation circuit is connected to the phase adjustment circuit, the phase adjustment circuit is an output terminal of the PWM pulse measurement unit, and the phase adjustment circuit is connected to the measurement probe. The photoelectric isolation circuit comprises a high-speed optical coupler, and the high-speed optical coupler is connected with the phase adjusting circuit. The wanted adjustment circuit comprises a triode which is respectively connected with a high-speed optocoupler and a measuring probe. A second pin of the high-speed optocoupler is connected with the electric energy conversion system, and a resistor R6 is connected between the second pin and the electric energy conversion system for limiting input current; an eighth pin of the high-speed optocoupler is respectively connected with an output end (+ 3.3V end) of the power circuit and a resistor R9, a resistor R9 is respectively connected with a collector of the triode and an anode of the measuring probe, the resistor R9 is used for limiting current flowing into the collector of the triode, and the triode is used for modulating the phase of an output signal by using 2N 222; a resistor R7 is connected between the sixth pin and the eighth pin of the high-speed optocoupler, the sixth pin of the high-speed optocoupler is connected with the base electrode of the triode through a resistor R8, the resistor R7 is a current-limiting resistor of the triode inside the high-speed optocoupler, and the resistor R8 is used for limiting the current flowing into the base electrode of the triode; and a fifth pin of the high-speed optocoupler is respectively connected with an emitter of the triode, an output grounding end of the power circuit and a negative electrode of the measuring probe.
The PWM pulse measuring unit is used for measuring a low-voltage high-speed driving signal of the switching tube, and the high-speed optical coupler in the photoelectric isolation circuit is 6N 137; when the input end of the PWM pulse measuring unit is at a high level, the output of the sixth pin of the high-speed optocoupler 6N137 is at a low level, and the input is reverse. In order to enable the output to be in phase with the input, a phase adjusting circuit is added behind the photoelectric isolation circuit, and 2N2222 is selected as a triode in the phase adjusting circuit.
And designing the input signal amplitude of the PWM pulse measuring unit to be not more than 6.5V. In the photoelectric isolation circuit, a diode in the chip between the second pin and the third pin of the high-speed optocoupler 6N137 recommends an input current of 10mA and a conduction voltage drop of 1.4V, so that R6 is selected to be 6.5V-1.4/10mA =510 omega. The resistor R7 is a current-limiting resistor of a 6N137 internal triode, and considering that the power supply of the PWM pulse measuring unit is 3.3V, the conduction voltage drop of the 6N137 internal triode is 0.3V, the R7 is 300 omega, and the maximum current flowing through the 6N137 internal triode is 10 mA. In the phase adjustment circuit, the resistor R8 is set to 300 Ω to limit the current flowing into the base stage of the transistor 2N2222, and considering that the power supply is 3.3V, the resistor R8 and the resistor R7 are connected in series to 3.3V, the voltage drop of the base stage of the transistor 2N2222 is 0.3V, and the maximum current flowing through the base of the transistor 2N2222 is 5 mA. Resistor R9 is taken to be 300 Ω for limiting the current flowing into the collector of transistor 2N2222, considering that the power supply is 3.3V, the on-state voltage drop of transistor 2N2222 is 0.3V, and the maximum current flowing through the collector of transistor 2N2222 is 10 mA.
As shown in fig. 5, the power circuit includes an AC/DC circuit, the AC/DC circuit converts 220V alternating current into positive and negative 15V direct current, an input end of the AC/DC circuit is connected to an external power source, an output end of the AC/DC circuit is connected to the DC/DC circuit, the hall voltage sensor and the hall current sensor, respectively, and the DC/DC circuit is connected to a power supply end of the PWM pulse measuring unit. A common-mode inductor LCM, a capacitor C2 and a resistor R10 are arranged between the input end of the AC/DC circuit and an external power supply, the output end of the common-mode inductor LCM is connected with the AC/DC circuit, the common-mode inductor LCM is used for suppressing common-mode interference, the A end of the input end of the common-mode inductor LCM is connected with the L end of the external power supply through a thermistor NTC and a FUSE FUSE, the FUSE FUSE is used for overheat protection of the circuit, and the thermistor NTC is used for suppressing surge current. The N end of the external power supply is connected with the B end of the input end of the common-mode inductance LCM, the E end of the external power supply is connected with the B end of the input end of the common-mode inductance LCM through a capacitor C4, a capacitor C3 is connected between the E end of the external power supply and the A end of the input end of the common-mode inductance LCM, and the capacitor C4 and the capacitor C3 are used for inhibiting common-mode interference; a voltage dependent resistor RV is connected between a common end of the thermistor NTC and the FUSE FUSE and an N end of an external power supply and is used for clamping voltage to a relatively fixed voltage value when overvoltage is input, so that protection of a rear-stage circuit is achieved, a capacitor C2 and a resistor R10 are connected between an A end and a B end of an input end of a common-mode inductor LCM after being connected in parallel, a resistor R10 is used for discharging capacitance energy after a module is powered down, and a capacitor C2 is used for suppressing differential mode interference.
The output end of the AC/DC circuit is provided with a +15V end and a-15V end and a GND end, and the GND end of the output end of the AC/DC circuit is connected with the GND end of the output end of the AC/DC isolation module; the +15V end is connected with the positive VO end of the output end of the AC/DC isolation module through an inductor L1, and an inductor L1 is used for filtering current ripples; the 15V terminal is connected with the negative VO terminal of the output terminal of the AC/DC isolation module through a diode D1 and an inductor L2, the inductor L2 is used for filtering current ripples, and the diode D1 is used for preventing current backflow; the resistor R11 and the capacitor C5 are connected in parallel and then connected between the positive VO end and the GND end of the output end of the AC/DC isolation module, the resistor R11 is used for simulating a load to enable the AC/DC isolation module to start and work, and the capacitor C5 is used for filtering low-frequency ripples; the capacitor C6 and the capacitor C7 are connected in parallel and then connected between the +15V end and the GND end, the capacitor C6 is used for filtering low-frequency ripples, and the capacitor C7 is used for filtering high-frequency ripples; a voltage regulator tube D2 and a capacitor C10 are connected in parallel and then connected between the anode of the diode D1 and the GND end, the voltage regulator tube D2 is used for stabilizing the negative 15 voltage, and the capacitor C10 is used for filtering low-frequency ripples; the capacitor C9 and the capacitor C8 are connected between the-15V terminal and the GND terminal after being connected in parallel, the capacitor C9 is used for filtering low-frequency ripples, and the capacitor C8 is used for filtering high-frequency ripples.
The DC/DC circuit comprises a DC/DC chip and a peripheral circuit, wherein the DC/DC chip is used for converting +15V into + 3.3V; the input end of the DC/DC circuit is a first pin VIN and a fifth pin GND of the DC/DC chip, and is respectively connected with the +15V end and the GND end of the output end of the power circuit; the output end of the DC/DC circuit is provided with a +3.3V end and a GND end which are respectively connected with the +3.3V end and the GND end of the output of the power circuit; the ON/OFF terminal of the DC/DC chip and the GND terminal of the DC/DC chip are connected with the GND terminal; the FEEDBACK end of the DC/DC chip is connected with the +3.3V end through a resistor R12, a capacitor C12 is connected in parallel with two ends of a resistor R12, a resistor R13 is connected between the FEEDBACK end and the ON/OFF end of the DC/DC chip, the resistor R12 and the resistor R13 are used for dividing the +3.3V voltage and then connecting the divided voltage to the FEEDBACK end FEEDBACK, and the capacitor C12 is used for providing a FEEDBACK path for the high-frequency ripple; the OUTPUT end of the DC/DC chip is connected with the +3.3V end through an inductor L3, the OUTPUT end of the DC/DC chip is connected with the GND end through a diode D3, the inductor L3 is used for filtering current ripples, and the diode D3 is used for providing an inductor follow current path; the capacitor C13 and the capacitor C11 are connected in parallel between the +3.3V end and the GND end, the capacitor C11 is used for filtering low-frequency ripples, and the capacitor C13 is used for filtering high-frequency ripples.
An AC/DC circuit adopts an AC/DC isolation module for converting 220V into positive and negative 15V, a FUSE FUSE is selected to be 2A/250V, a voltage dependent resistor RV is selected to be 14D471K, a resistor R10 is a bleeder resistor and is selected to be 1W/1M omega, a thermistor NTC is selected to be 10D-11, a capacitor C2 is selected to be a capacitor of 0.33uF/275V, capacitors C3 and C4 are Y capacitors of 222M/250V, and a common mode inductor LCM is selected to be UU9.8/50mH in model; the capacitors C5, C6, C9 and C10 are electrolytic capacitors, 25V/1000 mu F is selected, the diode D1 is SR5100, the voltage regulator tube D2 is selected to be 1N5352B, the capacitors C7 and C8 are CBB capacitors of 1 mu F/50V, the resistor R11 is 1K/0.5W, and the inductors L1 and L2 are bar inductors of 3.3 mu H; a DC/DC chip is adopted in a DC/DC circuit, a resistor R12=5.1K omega, a resistor R13=3K omega, a capacitor C12=0.1 mu F, an electrolytic capacitor of 47 mu F/25V is selected for a capacitor C11, an SS34 is selected for a capacitor C13=0.1 mu F, a diode D3, and a power inductor of 100 mu H is selected for an inductor L3.
The working process is as follows:
s1, when the voltage measuring unit is used for measurement, a proper measuring range is selected according to the amplitude of the voltage to be measured, the voltage to be measured is connected to the input end CH1in, CH1in or CH3in of the voltage measuring unit, and then the output signal CH1out, CH1out or CH3out of the voltage measuring unit corresponding to the connection is connected to an oscilloscope through the 1:1 attenuation voltage probe. In order to observe the waveform consistent with the actual voltage amplitude to be measured in the oscilloscope, the voltage attenuation option in the oscilloscope is determined according to the selection of the measuring range of the input end of the voltage measuring unit, and the voltage measuring ranges of 0-1400V, 0-700V and 0-70V respectively correspond to the voltage attenuation options of x 200, x 100 and x 10. At the moment, the isolation measurement work of the voltage to be measured can be finished by using a non-isolation oscilloscope and a conventional voltage probe.
S2, when the current measuring unit is used for measurement, the corresponding measuring range input end CH4in is connected in series into a current loop to be measured according to the amplitude of the current to be measured, and then the output signal of the current measuring unit is connected into an oscilloscope through a 1:1 attenuation voltage probe. In order to observe the waveform consistent with the actual current amplitude to be measured in the oscilloscope, the current attenuation option in the oscilloscope is determined according to the selection of the measuring range of the input end of the current measuring unit, and the current measuring ranges 0-5A, 0-10A and 0-25A respectively correspond to the current attenuation options of 1V/1A, 1V/2A and 1V/5A. At the moment, the current to be measured can be isolated and measured by using a non-isolated oscilloscope and a conventional voltage probe.
S3, using the PWM pulse measuring unit to ensure that the amplitude of the PWM pulse does not exceed 6.5V, then connecting the PWM pulse to be measured to the input end PWM1in or PWM2in of the PWM pulse measuring unit, and then connecting the output signal PWM1out or PWM2out of the PWM pulse measuring unit corresponding to the connection to the oscilloscope through the 1:1 attenuation voltage probe, and setting the voltage attenuation option in the oscilloscope as x 1. At the moment, the isolation measurement work of the voltage to be measured can be finished by using a non-isolation oscilloscope and a conventional voltage probe.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. The isolation module is characterized by comprising a voltage measuring unit, a current measuring unit, a PWM pulse measuring unit and a power circuit, wherein the input end of the power circuit is connected with an external power supply, the output end of the power circuit is respectively connected with the voltage measuring unit, the current measuring unit and the PWM pulse measuring unit, the input ends of the voltage measuring unit, the current measuring unit and the PWM pulse measuring unit are all connected with the electric energy conversion system, and the output ends of the voltage measuring unit, the current measuring unit and the PWM pulse measuring unit are all connected with an oscilloscope.
2. The isolation module for testing based on the electric energy conversion system according to claim 1, wherein a measurement probe is arranged on the oscilloscope, and the measurement probe is respectively connected with the output end of the voltage measurement unit, the output end of the current measurement unit and the output end of the PWM pulse measurement unit.
3. The isolation module for testing based on the electric energy conversion system according to claim 1 or 2, wherein the voltage measurement unit comprises a current limiting circuit, a hall voltage sensor and a first signal conversion circuit; the input end of the current limiting circuit is the positive electrode of the input end of the voltage measuring unit, the input end of the current limiting circuit is connected with the electric energy conversion system, the output end of the current limiting circuit is connected with the positive electrode of the input end of the Hall voltage sensor, the negative electrode of the input end of the Hall voltage sensor is the negative electrode of the input end of the voltage measuring unit, and the negative electrode of the input end of the Hall voltage sensor is connected with the electric energy conversion system; the power supply end of the Hall voltage sensor is connected with the output end of the power supply circuit; the first signal conversion circuit is connected between the output end of the Hall voltage sensor and the output grounding end of the power supply circuit, the first signal conversion circuit is the output end of the voltage measurement unit, and the first signal conversion circuit is connected with the measurement probe.
4. The isolation module for testing based on the power conversion system as claimed in claim 3, wherein the current measurement unit comprises a coil, a Hall current sensor and a second signal conversion circuit, the coil is connected with the power conversion system, the coil is wound on the Hall current sensor, a power supply end of the Hall current sensor is connected with an output end of the power supply circuit, the second signal conversion circuit is connected between the output end of the Hall current sensor and an output ground end of the power supply circuit, the second signal conversion circuit is an output end of the current measurement unit, and the second signal conversion circuit is connected with the measurement probe.
5. The isolation module for testing based on the power conversion system as claimed in claim 3, wherein the PWM pulse measurement unit comprises a photo-electric isolation circuit and a phase adjustment circuit, the photo-electric isolation circuit is an input terminal of the PWM pulse measurement unit, the photo-electric isolation circuit is respectively connected with the power conversion system, the photo-electric isolation circuit is connected with the phase adjustment circuit, the phase adjustment circuit is an output terminal of the PWM pulse measurement unit, and the phase adjustment circuit is connected with the measurement probe.
6. The isolation module for testing based on the electric energy conversion system according to claim 5, wherein the power circuit comprises an AC/DC circuit and a DC/DC circuit, an input end of the AC/DC circuit is connected with an external power supply, an output end of the AC/DC circuit is respectively connected with the DC/DC circuit, the Hall voltage sensor and the Hall current sensor, and an output end of the DC/DC circuit is connected with a power supply end of the PWM pulse measuring unit.
7. The isolation module for testing based on the electric energy conversion system according to claim 1, wherein the electric energy conversion system is an inverter, a frequency converter, a rectifier, a switching power supply or an electronic load.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020500191.9U CN211979022U (en) | 2020-04-08 | 2020-04-08 | Isolation module for testing based on electric energy conversion system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020500191.9U CN211979022U (en) | 2020-04-08 | 2020-04-08 | Isolation module for testing based on electric energy conversion system |
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| CN211979022U true CN211979022U (en) | 2020-11-20 |
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| CN202020500191.9U Active CN211979022U (en) | 2020-04-08 | 2020-04-08 | Isolation module for testing based on electric energy conversion system |
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