阅读说明：本技术 一种两电平逆变器开关管故障模拟的实验装置 (Experimental device for two-level inverter switch tube fault simulation ) 是由 尹帅 张亦琼 周丹 王庆义 于 2020-04-15 设计创作，主要内容包括：本发明提供一种两电平逆变器开关管故障模拟的实验装置,包括逆变主电路、信号采样电路、MCU控制模块、通讯传输模块、PC上位机,PC上位机根据需要模拟的故障类型,向MCU控制模块发送相应的故障指令；MCU控制模块接收指令后控制逆变主电路进行相应的故障模拟,并通过信号采样电路进行采样,随后将采样数据通过通讯传输模块发送至PC上位机,PC上位机进行实时数据处理。本发明的有益效果：可实现上位机对逆变器电流、电压数据的实时在线获取,方便之后的数据处理、故障分类、验证算法等,以便于开展相关学习研究；为后期开关管故障诊断的相关算法验证提供了物理验证平台,技术方案新颖且可行,有工程使用价值。(The invention provides an experimental device for simulating the fault of a switching tube of a two-level inverter, which comprises an inverter main circuit, a signal sampling circuit, an MCU control module, a communication transmission module and a PC upper computer, wherein the PC upper computer sends a corresponding fault instruction to the MCU control module according to the fault type to be simulated; the MCU control module receives the instruction and then controls the inverter main circuit to carry out corresponding fault simulation, the sampling is carried out through the signal sampling circuit, then the sampling data are sent to the PC upper computer through the communication transmission module, and the PC upper computer carries out real-time data processing. The invention has the beneficial effects that: the real-time online acquisition of the current and voltage data of the inverter by the upper computer can be realized, and the subsequent data processing, fault classification, verification algorithm and the like are facilitated, so that the development of relevant learning research is facilitated; a physical verification platform is provided for the verification of related algorithms of the switch tube fault diagnosis in the later period, the technical scheme is novel and feasible, and the method has engineering use value.)

1. The utility model provides an experimental apparatus of two level inverter switch tube fault simulation, its characterized in that, includes contravariant main circuit, signal sampling circuit, MCU control module, communication transmission module and PC host computer, wherein:

the MCU control module is connected with the inverter main circuit and the signal sampling circuit, and is used for carrying out pulse width modulation on the inverter main circuit and inverting the direct current in the inverter main circuit into alternating current;

the MCU control module is communicated with the PC upper computer through the communication transmission module, and the PC upper computer sends a corresponding fault instruction to the MCU control module through the communication transmission module according to the fault type of the switching tube to be simulated; the MCU control module receives a fault instruction and then controls the inverter main circuit to carry out corresponding fault simulation, and the signal sampling circuit samples the inverter main circuit;

and after the MCU control module packs the sampled data, the sampled data are sent to a PC upper computer through the communication transmission module, and the PC upper computer performs real-time data processing.

2. The experimental apparatus for simulating the failure of the switching tube of the two-level inverter according to claim 1, wherein the main inverter circuit is powered by a dc power source, and comprises three bridge arms full-bridge inverter circuits with 6 switching tubes, and the 6 switching tubes are driven by 3 switching tube driving chips, wherein each switching tube driving chip is connected to two switching tubes on the same bridge arm; and 3 the switch tube driving chips are connected with the MCU control module.

3. The experimental apparatus for simulating the fault of the switching tube of the two-level inverter according to claim 2, wherein the main inverter circuit further comprises 12 relays, wherein 6 relays are respectively connected in series to 6 switching tubes, the other 6 relays are respectively connected in parallel to 6 switching tubes, and the 6 relays connected in parallel to the switching tubes are further connected in series to 6 ptc thermistors.

4. The experimental apparatus for simulating the fault of the switching tube of the two-level inverter according to claim 3, wherein the relays are controlled by a relay driver chip, and the relay driver chip is connected to the MCU control module.

5. The experimental apparatus for simulating the failure of the switching tube of the two-level inverter according to claim 2, wherein the signal sampling circuit comprises an input power voltage sampling circuit, a three-way line voltage sampling circuit, and a three-way phase current sampling circuit, wherein the input power voltage sampling circuit performs a/D sampling on the dc power in the main inverter circuit, the three-way line voltage sampling circuit performs a/D sampling on the three-way line voltage signal of the full-bridge inverter circuit, the three-way phase current sampling circuit performs a/D sampling on the three-way phase current signal of the full-bridge inverter circuit, and the three-way phase current sampling circuit performs independent power supply by using three independent power supplies.

6. The experimental apparatus for simulating the faults of the switching tubes of the two-level inverter according to claim 5, further comprising a circuit protection module, wherein the circuit protection module is connected to the three-way phase current sampling circuit and the switching tube driving chip; the circuit protection module judges three paths of phase current signals, the current is limited in a normal range by adopting a threshold comparison circuit, and when an overcurrent and undercurrent condition occurs, the automatic turn-off of the switch tube driving chip is realized.

7. The experimental device for simulating the fault of the switching tube of the two-level inverter according to claim 1, wherein the communication transmission module and the MCU control module perform data transmission in an SPI communication manner, and transmit data processed by a TCP/IP protocol to the PC upper computer through an RJ45 network port.

8. The experimental apparatus for two-level inverter switching tube fault simulation according to claim 1, wherein the switching tube fault types include no fault, a single switching tube fault, 2 switching tube faults of the same bridge arm, 2 switching tube faults of the same upper or lower bridge arm, and 2 switching tube faults of a crossed bridge arm.

Technical Field

The invention relates to the technical field of power and electrical appliance fault diagnosis, in particular to an experimental device for fault simulation of a switching tube of a two-level inverter.

Background

Inverters are now widely used in various applications such as daily life, aerospace, industrial production, and energy supply. The distributed power generation utilizes various scattered renewable clean energy sources to generate power, can effectively solve the current energy utilization dilemma and the environmental pollution problem of the traditional thermal power generation, and improves the economical efficiency and reliability of the existing power system, thereby being widely applied in various countries of the world. Power generation systems of renewable energy sources all involve energy conversion with high power, high efficiency and high quality, and power electronic technology is one of key technologies.

The distributed power supply can output direct current and alternating current, so that electric energy with the same frequency and phase as the power grid needs to be converted through a power converter to be directly supplied to a user and incorporated into the power grid, and a large number of inverters are needed. If the inverter fails and cannot be diagnosed and repaired technically, irretrievable economic loss and safety risks are caused, and therefore safe, stable and reliable operation of the inverter is very important for a power system. It should be noted that, when a device of a certain phase of the inverter fails, the voltage and current of other phases may suddenly change, and therefore, it is important to research the fault location of the inverter. The traditional manual fault finding method is very difficult to diagnose faults quickly and accurately, not only takes long time, but also influences life production and power supply reliability.

After a short-circuit fault occurs to a switching tube of the inverter, the inside of the switching tube is sintered and finally converted into an open-circuit fault, so that the current field of inverter fault diagnosis mainly studies common open-circuit fault diagnosis in the faults of the switching tube, but the common diagnosis mode cannot obtain real-time current data of the inverter, only off-line data processing and fault diagnosis can be performed, and the problem of untimely diagnosis exists.

Disclosure of Invention

In view of the above, the invention provides an experimental device for simulating a fault of a switching tube of a two-level inverter, which simulates open-circuit and short-circuit faults of the switching tube of the two-level inverter, realizes communication with a PC upper computer compared with a general fault diagnosis platform, can realize real-time online acquisition of current and voltage data of the inverter by the PC upper computer by using related software, provides physical actual data for fault diagnosis of the two-level inverter in a later period, and facilitates a processing method of the data and algorithm verification of the fault diagnosis in the later period.

The invention provides an experimental device for simulating the fault of a switching tube of a two-level inverter, which comprises an inverter main circuit, a signal sampling circuit, an MCU control module, a communication transmission module and a PC upper computer, wherein:

the MCU control module is connected with the inverter main circuit and the signal sampling circuit, and is used for carrying out pulse width modulation on the inverter main circuit and inverting the direct current in the inverter main circuit into alternating current;

the MCU control module is communicated with the PC upper computer through the communication transmission module, and the PC upper computer sends a corresponding fault instruction to the MCU control module through the communication transmission module according to the fault type of the switching tube to be simulated; the MCU control module receives a fault instruction and then controls the inverter main circuit to carry out corresponding fault simulation, and the signal sampling circuit samples the inverter main circuit;

and after the MCU control module packs the sampled data, the sampled data are sent to a PC upper computer through the communication transmission module, and the PC upper computer performs real-time data processing.

Furthermore, the inverter main circuit is powered by a direct-current power supply, and a full-bridge inverter circuit with three groups of bridge arms is formed by 6 switching tubes, and the 6 switching tubes are driven by 3 switching tube driving chips, wherein each switching tube driving chip is connected with two switching tubes on the same bridge arm; and 3 the switch tube driving chips are connected with the MCU control module.

Further, the main inverter circuit further comprises 12 relays, wherein 6 relays are respectively connected in series to 6 switching tubes, the other 6 relays are respectively connected in parallel to 6 switching tubes, and the 6 relays connected in parallel to the switching tubes are also connected in series to 6 positive temperature coefficient thermistors.

Furthermore, the relays are controlled by relay driving chips, and the relay driving chips are connected with the MCU control module.

Furthermore, the signal sampling circuit comprises an input power supply voltage sampling circuit, a three-way line voltage sampling circuit and a three-way phase current sampling circuit, wherein the input power supply voltage sampling circuit performs A/D sampling on a direct-current power supply in the inverter main circuit, the three-way line voltage sampling circuit performs A/D sampling on three-way line voltage signals of the full-bridge inverter circuit, the three-way phase current sampling circuit performs A/D sampling on three-way phase current signals of the full-bridge inverter circuit, and the three-way phase current sampling circuit adopts three independent power supplies to independently supply power.

The circuit protection module is connected with the three-path phase current sampling circuit and the switching tube driving chip; the circuit protection module judges three paths of phase current signals, the current is limited in a normal range by adopting a threshold comparison circuit, and when an overcurrent and undercurrent condition occurs, the automatic turn-off of the switch tube driving chip is realized.

Furthermore, data transmission is carried out between the communication transmission module and the MCU control module in an SPI communication mode, and data processed by a TCP/IP protocol is sent to the PC upper computer through an RJ45 network port.

Further, the switching tube fault types include no fault, a single switching tube fault, 2 switching tube faults of the same bridge arm, 2 switching tube faults of the same upper or lower bridge arm, and 2 switching tube faults of crossed bridge arms.

The technical scheme provided by the invention has the beneficial effects that: the invention can realize the simulation of the open circuit and short circuit faults of the inverter switching tube, can realize the on-line data acquisition of the inverter, is convenient for subsequent data processing, fault classification, verification algorithm and the like, and is convenient for developing relevant study research.

Drawings

Fig. 1 is a structural diagram of an experimental apparatus for simulating a fault of a switching tube of a two-level inverter according to an embodiment of the present invention;

fig. 2 is a partial circuit diagram of an experimental apparatus for simulating a fault of a switching tube of a two-level inverter according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be further described with reference to the accompanying drawings.

Referring to fig. 1, an embodiment of the present invention provides an experimental apparatus for simulating a fault of a switching tube of a two-level inverter, including a power board 1, a control communication board 2, and a PC upper computer 3, where the power board 1 includes an inverter main circuit 11, a signal sampling circuit 12, and a circuit protection module 13, and the control communication board 2 includes an MCU control module 21 and a communication transmission module 22. The MCU control module 21 performs Sinusoidal Pulse Width Modulation (SPWM) on the inverter main circuit 11 to invert the dc power in the inverter main circuit 11 into ac power; the PC upper computer 3 sends a corresponding fault instruction to the MCU control module 21 through the communication transmission module 22 according to the type of switching tube fault to be simulated, the MCU control module 21 controls the inverter main circuit 11 to carry out corresponding switching tube fault simulation after receiving the instruction, and carries out A/D sampling on the inverter main circuit 11 through the signal sampling circuit 12; subsequently, the MCU control module 21 packages the sampled data and transmits the packaged sampled data to the PC upper computer 3 through the communication transmission module 22, and the PC upper computer 3 performs real-time data processing.

Referring to fig. 2, the main inverter circuit 11 includes 6 switching tubes T₁、T₂、T₃、T₄、T₅、T₆The three-phase inverter comprises a full-bridge inverter circuit and 3 switching tube driving chips, wherein the full-bridge inverter circuit is composed of three groups of bridge arms (A, B, C), and the full-bridge inverter circuit is connected with a 24V direct current power supply DC. Preferably, the switching tubes are N-channel MOS tubes and are driven by 3 switching tube driving chips IR2302, where each switching tube driving chip IR2302 drives two switching tubes located on the same bridge arm; the 3 switching tube driving chips IR2302 are connected with the MCU control module 21, the MCU control module 21 generates three SPWM modulation signals, controls the 3 switching tube driving chips IR2302 to drive 6 switching tubes to be switched on or switched off,therefore, the 24V direct-current power supply DC is inverted into three-phase alternating current with power frequency of 50Hz, wherein the switching frequency of the switching tube is 10 KHz.

The inverter main circuit 11 also adopts 12 relays K1-K12 which are respectively connected in series and in parallel with 6 switching tubes T₁、T₂、T₃、T₄、T₅、T₆And positive temperature coefficient thermistors R1-R6 are respectively connected in series with 6 relays (K7-K12 in figure 1) which are connected in parallel and are used for simulating the operation of protecting the circuit by limiting current in the case of short-circuit fault. The relay is controlled through a relay driving chip, the relay driving chip is connected with the MCU control module 21, the PC upper computer 3 sends different relay action instructions to the MCU control module 21 so as to give different fault types, and the simulation of various open-circuit and short-circuit faults in the inverter main circuit 11 is further realized.

Please refer to table 1, which is an open-circuit fault classification table of the inverter switching tube, and the PC upper computer provides a corresponding relay action command according to the fault type in table 1 to implement fault simulation. Specifically, the open-circuit fault types include no fault, a single switching tube fault, 2 switching tube faults of the same bridge arm, 2 switching tube faults of the same upper or lower bridge arm, and 2 switching tube faults of crossed bridge arms; referring to fig. 1, when there is no fault, the 6 relays K1-K6 connected in series to the switch tube are all in a closed state, and the 6 relays K7-K12 connected in parallel to the switch tube are in an open state; taking 2 switch tube faults of the same bridge arm as an example, the PC upper computer 3 randomly selects a fault switch tube as T₁、T₂And sends an instruction to the MCU control module 21, and the MCU control module 21 receives the instruction and then controls the relays K1 and K2 to turn off through the relay driver chip, thereby implementing the T-switch tube₁、T₂And (4) simulating the fault.

TABLE 1 open-circuit fault classification table for inverter switch tube

The signal sampling circuit 12 is connected with the MCU control module 21 and comprises an input power supply voltageThe sampling circuit, three line voltage sampling circuits and three phase current sampling circuits, wherein the input power supply voltage sampling circuit performs A/D sampling on the DC power supply; the three-path line voltage sampling circuit conditions the voltage signal into a 0-3.3V voltage signal by adopting an HWPT07 voltage transformer and a precise adjustable resistor and then inputs the voltage signal into the MCU control module 21, thereby realizing the three-path line voltage signal U after inversion_AB、U_BC、U_CAa/D sampling of (a); the three-path phase current sampling circuit adopts three independent power supplies to independently supply power and inputs the power into the MCU control module 21 through the AMC1100 isolation amplification chip, thereby realizing the three-path phase current signal I after inversion_A、I_B、I_Ca/D sampling of (1).

The circuit protection module 13 is connected with the three-path phase current sampling circuit and the switching tube driving chip IR2303, mainly judges three-path phase current signals, limits the current in a normal range by adopting a threshold comparison circuit, and realizes automatic turn-off of the switching tube driving chip IR2302 to protect the circuit when an overcurrent and undercurrent condition occurs.

MCU control module 21 adopts STM32F407ZET6 microcontroller, and the data that will signal sampling circuit 12 gathered are packed and are sent to communication transmission module 22. The communication transmission module 22 adopts a W5500 ethernet communication chip, performs data transmission with the MCU control module 21 in an SPI communication manner, and finally transmits data processed by a TCP/IP protocol to the PC upper computer 3 via an RJ45 network port.

The PC upper computer 3 receives data transmitted from an RJ45 network port by using an API (application program interface) in Matlab, generates related files, draws current waveforms in real time by the Matlab, sends fault instructions through network debugging software, and controls 12 relays K1-K12 to simulate open-circuit and short-circuit faults of the inverter.

Preferably, the experimental device adopts a three-phase star-shaped symmetrical inductance-resistance load r, the resistance value is adjustable in a sliding mode, and the inductance L is selected to be 100 mu H.

In this document, the terms front, back, upper and lower are used to define the components in the drawings and the positions of the components relative to each other, and are used for clarity and convenience of the technical solution. It is to be understood that the use of the directional terms should not be taken to limit the scope of the claims.

The features of the embodiments and embodiments described herein above may be combined with each other without conflict.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.