CN215772909U - Control compatible formula three-phase converter experimental system - Google Patents

Abstract

The utility model discloses a control-compatible three-phase converter experimental system which comprises a central processing unit, a central controller, a signal conditioning circuit module, a sampling protection module, an inversion driving module and a signal sampling module connected to input voltage or current, wherein the signal output end of the signal sampling module is respectively connected with the signal input end of the signal conditioning circuit module and the signal input end of the sampling protection module, the output end of the signal conditioning circuit module is connected with the sampling input end of the central processing unit, the output end of the sampling protection module is respectively connected with the central controller and the inversion driving module, the central processing unit is in communication connection with the central controller, and the signal output end of the central processing unit is connected with the input control end of the inversion driving module. The utility model realizes the interconversion between the three-phase alternating current and the direct current, adopts multiple protection means in the conversion experiment of the three-phase alternating current and the direct current, and avoids the short circuit phenomenon in the conversion process.

Description

Control compatible formula three-phase converter experimental system

Technical Field

The utility model belongs to the technical field of electronic experiments, and particularly relates to a control-compatible three-phase converter experiment system.

Background

The three-phase converter equipment is also called a three-phase inverter, is mainly controlled by a CPU (programmable logic controller or DSP controller), outputs sine waves intelligently with high quality, and has good fault protection functions (such as overvoltage, overcurrent and overload protection, and the like, and generally adopts software protection, namely, the controller is used for sampling voltage and current, and power failure protection is carried out after the voltage and the current exceed a safety range). The input of the converter is divided into an alternating current input type and a direct current input type. The alternating current input generally uses 220V mains supply, outputs three-phase 380V alternating current after rectification, boost and inversion, the direct current input generally has a certain voltage range, common direct current voltage is 12V, 24V, 36V and 48V, namely a lead-acid battery can be used for supplying power to equipment, the three-phase 380V alternating current voltage is output after chopping and boost and three-phase inversion, and the equipment can control the amplitude and frequency of an output sinusoidal signal after parameter setting. However, the existing three-phase inverter is single in purpose, and mainly used in a driving experiment of a three-phase motor, the output mode of a signal is also single (generally, two modes of a voltage closed loop and a frequency closed loop), and there are few three-phase conversion experimental devices which can be used for teaching in colleges and universities. Therefore, the three-phase converter equipment relates to high-voltage experiments, the three-phase alternating current and the direct current are mutually converted, required auxiliary equipment is combined together for connection when the current conversion experiment is carried out, overvoltage, overcurrent or heating can be caused frequently to cause overhigh temperature, certain dangerousness is realized, and the use safety of the equipment and the personal safety of a user are difficult to guarantee.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a control compatible three-phase converter experiment system, which realizes the mutual conversion between three-phase alternating current and direct current, adopts strict logic protection in a three-phase alternating current and direct current conversion experiment, thereby realizing multiple protection means and avoiding the short circuit phenomenon of the three-phase converter in the conversion process. In order to achieve the above object, the present invention adopts the following technical effects:

according to one aspect of the present invention, there is provided a control-compatible three-phase converter experimental system, the experimental system comprises a central processing unit, a central controller, a signal conditioning circuit module, a sampling protection module, an inversion driving module and a signal sampling module connected to input voltage or current, the signal output end of the signal sampling module is respectively connected with the signal input end of the signal conditioning circuit module and the signal input end of the sampling protection module, the output end of the signal conditioning circuit module is connected with the sampling input end of the central processing unit, the output end of the sampling protection module is respectively connected with the central controller and the inversion driving module, the central processing unit is in communication connection with the central controller, and the signal output end of the central processing unit is connected with the input control end of the inversion driving module.

Preferably, the signal conditioning circuit module includes an active adder circuit and a voltage inverter, the output end of the signal sampling module is connected to the negative input end of the active adder circuit, the output end of the active adder circuit is connected to the negative input end of the voltage inverter, and the output ends of the voltage inverter are respectively connected to the sampling input end of the central processing unit.

Preferably, the experimental system further comprises a power protection circuit and an external reset circuit, the sampling protection module comprises a plurality of comparison and discrimination circuits and a plurality of control logic circuits, a collection input end of each comparison and discrimination circuit is electrically connected with an output end of the signal sampling module, an output end of each comparison and discrimination circuit is connected with a first input end of one control logic circuit, an output end of each control logic circuit is respectively connected with a feedback input end of the central controller and an enabling input end of the inversion driving module, an output end of the external reset circuit is respectively connected with a second input end of each control logic circuit, and an output end of the control logic circuit is respectively connected with an input end of the power protection circuit and an enabling input end of the inversion driving module.

Preferably, the comparison and discrimination circuit comprises a comparison amplifier and an inverter, the output end of the signal sampling module is connected with the acquisition input end of the comparison amplifier, the output end of the comparison amplifier is connected with the input end of the inverter, the multi-path control logic circuit comprises an RS trigger, a multi-input NAND gate, a resistor R20 and a diode D20, the output end of the phase inverter is connected with the first input end of the RS trigger, the output end of the external reset circuit is connected with the second input end of the RS trigger, the first output end of the RS flip-flop is connected to the anode of the diode D20 and the input end of the multi-input nand gate respectively, the second output end of the RS trigger is connected with the central controller through a resistor R20, the cathode of the diode D20 is connected with the input end of the power protection circuit, and the output end of the multi-input NAND gate is connected with the enable input end of the inversion driving module.

Preferably, the inverter driving module includes a PWM driving circuit, a boost isolation module and an IGBT power inverter module, an output terminal of the multi-input nand gate is connected to an enable input terminal of the PWM driving circuit, a signal output terminal of the central processing unit is connected to an input control terminal of the PWM driving circuit, and a driving output terminal of the PWM driving circuit is connected to an input control terminal of the IGBT power inverter module through the boost isolation module.

Preferably, the PWM driving circuit includes a first two-input nand gate, a second two-input nand gate, a third two-input nand gate, a resistor R30, a resistor R31, a resistor R32, a diode D31, a diode D32 and a diode D33, wherein a first signal output end and a second signal output end of the cpu are respectively connected to an anode of the diode D31 and an anode of the diode D32, a cathode of the diode D31 is respectively connected to one end of the resistor R30, a first input end of the first two-input nand gate and a first input end of the second two-input nand gate, a cathode of the diode D32 is respectively connected to one end of the resistor R31, a second input end of the first two-input nand gate and a second input end of the third two-input nand gate, an output end of the first two-input nand gate is connected to one end of the resistor R32, and another end of the resistor R32 is respectively connected to an anode of the diode D33, a second two-input nand gate, a third two-input nand gate, a diode D3583, a diode D32, and a diode D32, The second input end of the second two-input NAND gate is connected with the first input end of the third two-input NAND gate, the output of the second two-input NAND gate is connected with the first input control end of the boosting isolation module, and the output end of the third two-input NAND gate is connected with the second input control end of the boosting isolation module.

In a further preferred embodiment of the foregoing scheme, the first input terminal of the first two-input nand gate and the first input terminal of the second two-input nand gate are further connected to a first external signal connection terminal, and the second input terminal of the first two-input nand gate and the second input terminal of the third two-input nand gate are further connected to a second external signal connection terminal.

In summary, due to the adoption of the technical scheme, the utility model has the following technical effects:

(1) the three-phase converter experimental system realizes the interconversion between three-phase alternating current and direct current; the experimental system has two working modes, namely, the first working mode is that the three-phase alternating current side is used as input to control the IGBT power inverter module to be switched on and switched off, the direct current side is used as output, direct current can be obtained at the direct current side, and three-phase controllable rectification is realized; secondly, the direct current side is used as input to control the IGBT power inversion module to be switched on and off, the three-phase alternating current side is used as output, and three-phase alternating current can be obtained at the three-phase side to realize three-phase inversion; simultaneously collecting alternating current voltage and direct current voltage of the three-phase inverter, and analyzing and judging the collected three-phase alternating current side and the collected direct current side;

(2) the utility model is taken as experimental equipment, multiple protection design is carried out in the process of realizing an inversion experiment according to a safe and reliable design concept strictly, and hardware protection logic consisting of an active operational amplifier comparator, a sampling circuit and an AC/DC contactor is adopted to carry out strict logic protection on a PWM signal, so that multiple protection means are realized, and the phenomenon that an upper pipe and a lower pipe of the same bridge arm of a conversion circuit of a three-phase full-bridge converter are conducted simultaneously to cause a short circuit is avoided;

(3) the utility model carries out diversified design of experimental modes, can realize the signal butt joint of an external controller (such as a dsPACE) and equipment through a compatible data interface, and realizes the control function of the equipment. The method is convenient for students to quickly build simulation model verification and can also train the embedded programming capability of the students; the universal controller mode is an expression of control compatibility.

Drawings

FIG. 1 is a system schematic of an experimental system for controlling a compatible three-phase converter according to the present invention;

FIG. 2 is a schematic diagram of a signal conditioning circuit block of the present invention;

FIG. 3 is a circuit diagram of a signal conditioning circuit block of the present invention;

FIG. 4 is a circuit schematic of the sample protection module of the present invention;

FIG. 5 is a schematic diagram of an inverter driver module of the present invention;

fig. 6 is a schematic diagram of an IGBT power inverter module of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings by way of examples of preferred embodiments. It should be noted, however, that the numerous details set forth in the description are merely for the purpose of providing the reader with a thorough understanding of one or more aspects of the present invention, which may be practiced without these specific details.

As shown in fig. 1, according to an aspect of the present invention, there is provided a control-compatible three-phase converter experimental system, which includes a central processing unit, a central controller, a signal conditioning circuit module, a sampling protection module, an inversion driving module, and a signal sampling module connected to an input voltage or current, wherein a signal output end of the signal sampling module is connected to a signal input end of the signal conditioning circuit module and a signal input end of the sampling protection module, respectively, an output end of the signal conditioning circuit module is connected to a sampling input end of the central processing unit, an output end of the sampling protection module is connected to the central controller and the inversion driving module, respectively, the central processing unit receives a signal of the signal conditioning circuit module and then performs linear derivation to obtain actual parameter values (voltage, current, etc.) of a device, the central processing unit is in communication connection with the central controller, and the signal output end of the central processing unit is connected with the input control end of the inversion driving module. The central processing unit uses a DSP processor, the model number of the DSP processor is a DSP28335 processor, the DSP processor is mainly used for sending PWM signals to carry out power conversion control, three-phase signals (three-phase voltage and three-phase current) are sampled, and code input signals input by an external three-phase motor encoder are collected and read to be used as control signals; the central controller uses STM32 series controller, and is mainly used for monitoring equipment operation and controlling an alarm display module to perform alarm operation, and the alarm display module is composed of a serial port liquid crystal touch screen capable of performing data display and man-machine interaction.

In the present invention, as shown in fig. 1, fig. 2 and fig. 3, the signal conditioning circuit module includes an active operational amplifier adder and a voltage inverter, an output end of the signal sampling module is connected to a negative input end of the active operational amplifier adder, an output end of the active operational amplifier adder is connected to a negative input end of the voltage inverter, and output ends of the voltage inverter are respectively connected to a sampling input end of the central processing unit. The Hall sensor is connected with an inversion output end of an inversion driving module (IGBT power inversion module) on three-phase alternating current or direct current, signals output by the IGBT power inversion module of the inversion driving module are collected, signal conditioning is carried out through an active operational amplifier adder formed by an operational amplifier U11 and a voltage inverter formed by an operational amplifier U12, the output sampling voltage is 0-3V (or 0-5), the voltage output by the operational amplifier U12 is sent to a central processing unit through a resistor R19 for AD sampling conversion and is sent to central control through a resistor R190 for AD sampling conversion, and the central control sends collected converted information to an alarm display module for display and alarm; the voltage of three-phase alternating current sampling is large, the voltage is positive or negative, so that signal attenuation and signal lifting are required to be carried out in sampling, the Hall sensor can carry out signal attenuation on alternating current voltage and alternating current, but the signal still has positive or negative, the signal is required to be carried out on the collected signal after the signal is collected by the Hall sensor, the voltage is lifted (amplified), secondary attenuation is carried out through the inverse proportional amplifier, and after the signal conditioning is finished, the sampling output end generates a voltage signal suitable for being collected by the central processing unit to carry out AD conversion.

In the present invention, as shown in fig. 1 and 4, the experimental system further includes a power protection circuit and an external reset circuit, the sampling protection module comprises a plurality of comparison and discrimination circuits and a plurality of control logic circuits, the acquisition input end of each comparison and discrimination circuit is electrically connected with the output end of the signal sampling module, the output end of each comparison and discrimination circuit is connected with the first input end of one control logic circuit, the output end of each control logic circuit is respectively connected with the feedback input end of the central processing unit, the feedback input end of the central controller and the enabling input end of the inversion driving module, the output end of the external reset circuit is respectively connected with the second input end of each control logic circuit, the output end of the control logic circuit is respectively connected with the input end of the power supply protection circuit and the enabling input end of the inversion driving module; the comparison and discrimination circuit comprises a comparison amplifier and an inverter, the output end of the signal sampling module is connected with the acquisition input end of the comparison amplifier, the output end of the comparison amplifier is connected with the input end of the inverter, the multi-path control logic circuit comprises an RS trigger, a multi-input NAND gate, a resistor R20 and a diode D20, the output end of the phase inverter is connected with the first input end of the RS trigger, the output end of the external reset circuit is connected with the second input end of the RS trigger, the first output end of the RS flip-flop is connected to the anode of the diode D20 and the input end of the multi-input nand gate respectively, the second output end of the RS trigger is connected with the central controller through a resistor R20, the cathode of the diode D20 is connected with the input end of the power protection circuit, and the output end of the multi-input NAND gate is connected with the enable input end of the inversion driving module. The sampling protection module of the utility model oversamples each path of voltage or voltage VadN output by a current Hall sensor and a reference voltage VdN and sends the voltage VadN and the reference voltage VdN into a comparison and judgment circuit for comparison, the comparison and judgment circuit consists of a comparator U20_ n and an inverter U21_ n, whether a sampling point signal exceeds a threshold value is judged by comparison, the output of the comparator U20_ n is connected with the inverter U21_ n to modify the logic of a comparison output signal, the accuracy and novelty of signal judgment are improved, the generation of interference signals is prevented, then the sampling protection module is sent into a multi-input NAND gate U22 through an RS trigger to carry out logic judgment, then a PWM _ enable signal (PWM enable driving signal) is output, meanwhile, an external protection signal can be generated by a central processing unit (DSP processing unit) or an external controller (STM32 controller) to participate in the logic operation judgment of a multi-input NAND gate U22, and the state of the output signal PWM _ enable of the multi-input U22 is changed, further controlling the on-off of the relay U24, controlling the power-on state of the equipment and the state of PWM waves, when the PWM _ enable signal is logic '0', indicating that a certain sampling signal exceeds a threshold value (normally logic '1'), specifically, which sampling point signal exceeds the threshold value, outputting the signal of the sampling point to a central controller (STM32 controller) by an RS trigger for identification, outputting the signal to an alarm display circuit for displaying and alarming, disabling the PWM signal output by a PWM driving circuit of an inverter driving module by the output PWM _ enable signal, controlling the power-off of the relay U24 by the PWM _ enable signal, cutting off the AC 220V mains supply L by the relay U24 when the AC 220V mains supply L is accessed, and stopping all power supply work of the equipment when the voltage output by a pin L of the relay U24 is 0; after the control logic circuit is triggered, the RS trigger circuit needs to be reset, the reset method is that a logic '0' level signal is input into a reset pin of the RS trigger circuit, the reset signal is output through an external reset circuit under the normal condition to enable the reset pin of the RS trigger to be a logic signal '1', wherein RES _ A, RES _ B, RES _ C of the external reset circuit is three independent reset trigger signals, the three independent reset signals are respectively driven to be sent into an NPN triode V1 through respective switch diodes for judgment, RES _ A is a reset signal sent by a central processing unit, RES _ B is a reset signal sent by an external controller, RES _ C is a trigger signal sent by an external reset key, the logic '1' signal triggers the NPN V1 to be conducted, the potential of the reset pin of the RS trigger is pulled down to complete reset, and the triode V1 is equivalent to a switch device, the alternating current 220V commercial power L line is connected with a normally-closed point of the relay U24, namely the voltage Uo output by the relay U is communicated with the voltage L under the normal condition, when the PWM _ enal signal is abnormal to be logic '0', the triode V1 is conducted, the output end Uo of the relay U24 is communicated with the suspension pin NC, the equipment is powered off, and all power supply work of the equipment is stopped.

In the present invention, as shown in fig. 4, 5 and 6, the inverter driving module includes a PWM driving circuit, a boost isolation module and an IGBT power inverter module, an output end of the multi-input nand gate is connected to an enable input end of the PWM driving circuit, a signal output end of the central processing unit is connected to an input control end of the PWM driving circuit, and a driving output end of the PWM driving circuit is connected to an input control end of the IGBT power inverter module through the boost isolation module; the PWM driving circuit comprises a first two-input NAND gate U31, a second two-input NAND gate U32, a third two-input NAND gate U33, a resistor R30, a resistor R31, a resistor R32, a diode D31, a diode D32 and a diode D33, wherein a first signal output end and a second signal output end of the CPU are respectively connected with an anode of a diode D31 and an anode of the diode D32, a cathode of the diode D31 is respectively connected with one end of the resistor R30, a first input end of the first two-input NAND gate and a first input end of the second two-input NAND gate, a cathode of the diode D32 is respectively connected with one end of the resistor R31, a second input end of the first two-input NAND gate and a second input end of the third two-input NAND gate, an output end of the first two-input NAND gate is connected with one end of the resistor R32, and the other end of the resistor R32 is respectively connected with an anode of the diode D33, In the utility model, the IGBT power inverter module comprises bridge arms (IGBT power switch tubes G1-G6) consisting of 6 IGBT power switch tubes, as shown in FIG. 6, after signals are sent to a central processing unit (DSP processor) by using voltage or current signals sampled by the module for operation AD operation conversion, the bridge arms consisting of 6 IGBT power switch tubes are controlled by two paths of PWM1 and PWM1 signals output by the central processing unit (DSP processor), and the PWM1 signals pass through the first input end of a first input NAND gate U31 and the first input end of a second input NAND gate U32 of a PWM driving circuit, The PWM2 signal is logically determined by the second input end of the first input nand gate U31 and the first input end of the third input nand gate U33 of the PWM driving circuit, and the output signal after each determination is sent to the corresponding first boost isolator U34 (the second boost isolator U35) through the resistor R33 (the resistor R35, etc.), so that the central processing unit (DSP processor) outputs the modulated wave to control the bridge arm composed of 6 IGBT power transistors, as shown in fig. 6, it can be seen from the bridge arm composed of 6 IGBT power transistors that the upper and lower two transistors of the same bridge arm cannot be simultaneously conducted, for example, G1 and G4 cannot be simultaneously conducted, or else, a short circuit phenomenon is caused by a voltage drop on the dc side. Therefore, in the PWM driving circuit in which the output modulation wave is PWM phase-controlled and protected by the central processing unit (DSP processor), as shown in fig. 5, when PWM1 and PWM2 are both logic signal "1", PWM _1 and PWM _2 are also logic signal "1", and there is no signal on the G1 and G2 sides. If and only if one of the PWM1 and PWM2 is "1" and the other is "0", signals are output from the G1 and G2 sides. When the PWM _ enable signal is logic signal "0", the PWM1 and PWM2 signals are disabled. The optical coupling isolator in the boost isolation module is used for amplifying PWM signals (the control voltage of a G1-G6 switching tube is 15V) and isolating strong current signals and weak current control signals, and the on-off sequence of 6 IGBT power tubes is sequentially controlled, so that direct current is converted into three-phase alternating current.

As another embodiment of the present invention, in order to compatibly perform a three-phase converter experiment, a general PWM control signal interface or a general device signal sampling port is reserved to implement a device-compatible multi-type external controller to perform a control experiment on a system, a first external signal connection terminal PWM _ a is further connected to a first input terminal of the first two-input nand gate U31 and a first input terminal of the second two-input nand gate U32, a second external signal connection terminal PWM _ b is further connected to a second input terminal of the first two-input nand gate and a second input terminal of the third two-input nand gate, signals output by the external controller respectively pass through the first external signal connection terminal PWM _ a and the second external signal connection terminal PWM _ b, signals input by the first external signal connection terminal PWM _ a pass through the diode D31 and are respectively sent to a first input terminal of the first two-input nand gate U31 and a first input terminal of the second two-input nand gate U32, the input signal of the second external signal connection terminal PWM _ b is respectively sent to the second input end of the first two-input NAND gate U31 and the second input end of the third two-input NAND gate U33 through the diode D32; after PWM1 and PWM2 control signals are output by a central processing unit (DSP processor) temporarily, in order to carry out compatibility experiments, at the moment, a PWM driving circuit for PWM phase control protection is output by an external controller (STM32 series controller), so that the effect of an optical coupling isolator in the boost isolation module is to amplify PWM signals (the control voltage of a G1-G6 switching tube is 15V) and isolate strong current signals and weak current control signals, the PWM driving circuit sequentially controls the turn-on or turn-off sequence of 6 IGBT power tubes, and direct current is converted into three-phase alternating current.

In the utility model, with reference to fig. 1 to 6, in the process of performing a three-phase current transformation experiment, when three-phase alternating current is inverted into direct current, U, V, W three-phase alternating current input from the three-phase power grid side is sent to a bridge arm power inversion module composed of 6 IGBT power tubes, a bridge arm composed of 6 IGBT power tubes is controlled by a central processing unit (DSP processor), a voltage signal acquired by the signal acquisition module is sent to the central processing unit (DSP processor) to perform AD conversion operation, the central processing unit (DSP processor) outputs a modulation wave for controlling the bridge arm composed of 6 IGBT power tubes after the operation, so as to control the 6 IGBT power tubes to invert the three-phase alternating current to output direct current voltage, and the voltages output by the direct current terminals + DC and-DC of the bridge arm are filtered and then output to a direct current load to supply power; when the direct-current voltage is inverted into the three-phase alternating current, the direct-current terminals + DC and-DC of the bridge arms input direct current, the comparison and judgment circuit collects the alternating current output by the direct-current voltage through the inversion of the bridge arms, when a central processing unit (DSP) processes the direct current and the three-phase alternating current output by the three-phase alternating current terminals U, V, W of the bridge arms is supplied to an alternating-current load by controlling the switching sequence of the 6 IGBT power tubes, the direct current is converted into the three-phase alternating current; when the U, V, W end on the three-phase power grid side is used as input, the direct-current side rectification output can be realized at the direct-current terminal + DC and-DC by controlling the on-off of the G1-G6 switching tubes; when the direct current terminal + DC and-DC are used as input, the switching on or off of the G1-G6 switching tube is controlled, and the rectification output at the alternating current side can be realized at the U, V, W end of the three-phase power grid side, so that the utility model can realize power conversion of direct-alternating current, alternating current-direct current and the like, and can realize various power conversion functions of alternating current-direct current-alternating current, alternating current-direct current-alternating current → alternating current-direct current-alternating current when a plurality of IGBT power inverter modules are combined in series.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.

Claims (7)

1. The utility model provides a control compatible formula three-phase converter experimental system which characterized in that: the experimental system comprises a central processing unit, a central controller, a signal conditioning circuit module, a sampling protection module, an inversion driving module and a signal sampling module connected to input voltage or current, wherein the signal output end of the signal sampling module is respectively connected with the signal input end of the signal conditioning circuit module and the signal input end of the sampling protection module, the output end of the signal conditioning circuit module is connected with the sampling input end of the central processing unit, the output end of the sampling protection module is respectively connected with the central controller and the inversion driving module, the central processing unit is in communication connection with the central controller, and the signal output end of the central processing unit is connected with the input control end of the inversion driving module.

2. The control-compatible three-phase converter experimental system of claim 1, wherein: the signal conditioning circuit module comprises an active adder circuit and a voltage phase inverter, the output end of the signal sampling module is connected with the negative input end of the active adder circuit, the output end of the active adder circuit is connected with the negative input end of the voltage phase inverter, and the output end of the voltage phase inverter is respectively connected with the sampling input end of the central processing unit.

3. The control-compatible three-phase converter experimental system of claim 1, wherein: the experimental system further comprises a power supply protection circuit and an external reset circuit, the sampling protection module comprises a plurality of comparison and judgment circuits and a plurality of control logic circuits, the acquisition input end of each comparison and judgment circuit is electrically connected with the output end of the signal sampling module, the output end of each comparison and judgment circuit is connected with the first input end of one control logic circuit, the output end of each control logic circuit is respectively connected with the feedback input end of the central controller and the enabling input end of the inversion driving module, the output end of the external reset circuit is respectively connected with the second input end of each control logic circuit, and the output end of the control logic circuit is respectively connected with the input end of the power supply protection circuit and the enabling input end of the inversion driving module.

4. The control-compatible three-phase converter experimental system of claim 3, wherein: the comparison and discrimination circuit comprises a comparison amplifier and an inverter, the output end of the signal sampling module is connected with the acquisition input end of the comparison amplifier, the output end of the comparison amplifier is connected with the input end of the inverter, the multi-path control logic circuit comprises an RS trigger, a multi-input NAND gate, a resistor R20 and a diode D20, the output end of the phase inverter is connected with the first input end of the RS trigger, the output end of the external reset circuit is connected with the second input end of the RS trigger, the first output end of the RS flip-flop is connected to the anode of the diode D20 and the input end of the multi-input nand gate respectively, the second output end of the RS trigger is connected with the central controller through a resistor R20, the cathode of the diode D20 is connected with the input end of the power protection circuit, and the output end of the multi-input NAND gate is connected with the enable input end of the inversion driving module.

5. The control-compatible three-phase converter experimental system of claim 4, wherein: the inverter driving module comprises a PWM driving circuit, a boosting isolation module and an IGBT power inverter module, the output end of the multi-input NAND gate is connected with the enabling input end of the PWM driving circuit, the signal output end of the central processing unit is connected with the input control end of the PWM driving circuit, and the driving output end of the PWM driving circuit is connected with the input control end of the IGBT power inverter module through the boosting isolation module.

6. The control-compatible three-phase converter experimental system of claim 5, wherein: the PWM driving circuit comprises a first two-input NAND gate, a second two-input NAND gate, a third two-input NAND gate, a resistor R30, a resistor R31, a resistor R32, a diode D31, a diode D32 and a diode D33, wherein a first signal output end and a second signal output end of the central processing unit are respectively connected with an anode of a diode D31 and an anode of a diode D32, a cathode of the diode D31 is respectively connected with one end of the resistor R30, a first input end of the first two-input NAND gate and a first input end of the second two-input NAND gate, a cathode of the diode D32 is respectively connected with one end of the resistor R31, a second input end of the first two-input NAND gate and a second input end of the third two-input NAND gate, an output end of the first two-input NAND gate is connected with one end of the resistor R32, and the other end of the resistor R32 is respectively connected with an anode of a diode D33, an anode of the diode D33, a second input NAND gate, a second input of the diode D3583 and a first input NAND gate, a second input of the diode D32 and a second input NAND gate, The second input end of the second two-input NAND gate is connected with the first input end of the third two-input NAND gate, the output of the second two-input NAND gate is connected with the first input control end of the boosting isolation module, and the output end of the third two-input NAND gate is connected with the second input control end of the boosting isolation module.

7. The control-compatible three-phase converter experimental system of claim 6, wherein: the first input end of the first two-input NAND gate and the first input of the second two-input NAND gate are also connected with a first external signal connecting terminal, and the second input end of the first two-input NAND gate and the second input of the third two-input NAND gate are also connected with a second external signal connecting terminal.

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