Motor protection circuit of motor protector

Abstract

The utility model provides a motor protection circuit of a motor protector, which is characterized in that a master control circuit is electrically connected with a current signal processing circuit, a voltage signal processing circuit, a power metering circuit, a communication circuit, an overcurrent protection circuit, an overvoltage protection circuit, a logic protection circuit and a motor driving circuit; the current signal processing circuit and the voltage signal processing circuit are electrically connected with the power metering circuit, the overcurrent protection circuit, the overvoltage protection circuit and the logic protection circuit are electrically connected with the motor driving circuit, the output end of the motor driving circuit is electrically connected with the inverter, and the inverter is electrically connected with a three-phase motor. By detecting the working voltage, current and power of the motor, the working condition of the motor can be better and more comprehensively mastered. Besides, if over-current, over-voltage and logic control errors exist, motor faults can be timely and accurately detected, a protection function is realized by controlling the motor driving circuit, and damage to the motor is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor protector technical field, concretely is a motor protector motor protection circuit. BACKGROUND

[0002] Three-phase motor is one of the devices widely used in electromechanical industry, and normal power output of the motor is the prerequisite for normal work of the driven device. However, the application environment of most motors is very poor, especially in thermal power plants, mines, steel, metallurgy and petrochemical enterprises, the motor works in high temperature, high humidity and dusty conditions for a long time, which can easily cause the motor to have faults such as open phase, under load, over voltage, leakage, blocked rotation and overload. In the actual use process, in addition to the poor operating environment, the operation under the super technical condition is also the main reason for causing various motor faults. The three-phase motor will also often have motor damage due to various reasons of power grid, load and motor itself. The direct and indirect losses caused by motor faults or damage are quite huge. Therefore, maintaining the stable operation of the motor has been a long-standing concern. It is very important to maintain the normal operation of the motor and ensure the safety of production by designing and using a device that can timely and accurately detect the occurrence of faults, analyze the fault characteristics to determine the fault cause and provide protection. SUMMARY

[0003] The utility model wants to solve the technical problem to provide a kind of motor protector motor protection circuit, to solve the deficiency of prior art described in background.

[0004] To solve the above technical problems, the embodiment of the utility model provides the following technical scheme: a kind of motor protector motor protection circuit, including main control circuit, current signal processing circuit, voltage signal processing circuit, power metering circuit, communication circuit, overcurrent protection circuit, overvoltage protection circuit, logic protection circuit, motor drive circuit, inverter, three-phase motor, the main control circuit is connected with current signal processing circuit, voltage signal processing circuit, power metering circuit, communication circuit, overcurrent protection circuit, overvoltage protection circuit, logic protection circuit, motor drive circuit, the current signal processing circuit, voltage signal processing circuit are all connected with power metering circuit, the overcurrent protection circuit, overvoltage protection circuit, logic protection circuit are all connected with motor drive circuit, the output end of motor drive circuit is connected with inverter, the inverter is connected with three-phase motor.

[0005] Preferably, the main control circuit is an ARM processor or a DSP processor.

[0006] Preferably, the power metering circuit is a three-phase electric energy special metering chip ATT7022B.

[0007] Preferably, the communication circuit is an RS485 communication circuit.

[0008] Preferably, the over-current protection circuit is a current detection amplification circuit based on a voltage comparator LM311.

[0009] Preferably, the over-voltage protection circuit comprises an amplification circuit based on an operational amplifier TLC2262, an absolute value circuit based on a two-stage operational amplifier TLC2262 and a comparison amplification circuit based on LM339, which are electrically connected in sequence.

[0010] Preferably, the motor drive circuit is an IGBT switching tube drive circuit based on an IR2130 chip.

[0011] Preferably, the inverter is a three-phase IGBT inverter circuit.

[0012] The beneficial effects of the above technical solutions of the utility model are as follows:

[0013] The current and voltage signals are sampled by a mutual inductor, and then are connected to a power metering circuit and a master control circuit through a current processing circuit and a voltage processing circuit, respectively, the power data of the motor obtained by the power metering circuit is sent to the master control circuit, so that the working condition of the motor can be better and more comprehensively mastered. In addition, if the collected voltage and current signals have overcurrent, overvoltage and logic control error, the occurrence of motor failure can be detected in time and accurately, and the protection function is realized by controlling the motor drive circuit, so that the damage of the motor is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a motor protection circuit control system principle block diagram of the utility model's motor protector;

[0015] Figure 2 It is a current signal processing circuit principle diagram of the utility model's motor protector motor protection circuit;

[0016] Figure 3 It is a voltage signal processing circuit principle diagram of the utility model's motor protector motor protection circuit;

[0017] Figure 4 It is a motor drive circuit principle diagram of the utility model's motor protector motor protection circuit;

[0018] Figure 5 It is an over-current protection circuit principle diagram of the utility model's motor protector motor protection circuit;

[0019] Figure 6 It is an over-voltage protection circuit principle diagram of the utility model's motor protector motor protection circuit;

[0020] Figure 7 The motor protection circuit logic protection circuit principle diagram of the motor protector. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and advantages to be solved by the utility model more clear, the following will be described in detail in combination with the drawings and specific embodiments.

[0022] As Figure 1 shown, the utility model provides a kind of motor protector motor protection circuit, including main control circuit 1, current signal processing circuit 2, voltage signal processing circuit 3, power metering circuit 4, communication circuit 5, overcurrent protection circuit 6, overvoltage protection circuit 7, logic protection circuit 8, motor drive circuit 9, inverter 10, three-phase motor 11, main control circuit 1 is electrically connected with current signal processing circuit 2, voltage signal processing circuit 3, power metering circuit 4, communication circuit 5, overcurrent protection circuit 6, overvoltage protection circuit 7, logic protection circuit 8, motor drive circuit 9, current signal processing circuit 2, voltage signal processing circuit 3 are all electrically connected with power metering circuit 4, overcurrent protection circuit 6, overvoltage protection circuit 7, logic protection circuit 8 are all electrically connected with motor drive circuit 9, motor drive circuit 9 output end is electrically connected with inverter 10, inverter 10 is electrically connected with three-phase motor 11.

[0023] Main control circuit 1 is ARM processor or DSP processor, such as domestic Feiteng processor, Kunpeng processor, Kirin chip or Ruikaiwei RK3588 processor, for the electric signal control of entire protection.

[0024] Power metering circuit 4 is three-phase electric energy special metering chip ATT7022B, and ATT7022B is a high-precision three-phase electric energy special metering chip, applicable to three-phase three-wire and three-phase four-wire application.

[0025] Communication circuit 5 is RS485 communication circuit, and the main device of communication circuit has level conversion chip SN65LBC184, optocoupler chip 6N137 and TLP521, and each parameter here will not be described.

[0026] As Figure 2As shown, this is the current signal processing circuit 2. The changes in the magnitude of the current signal acquired by the current transformer are converted into changes in the voltage signal by an operational amplifier for further processing. The current processing circuit is divided into two parts. The signal processed by the upper part is connected to the power metering chip ATT7022B, and the signal processed by the lower part is connected to the main control circuit. The upper part first passes through an isolation circuit to prevent the input and output signals from interfering with each other. This is because the main control circuit and the power metering circuit have different requirements for the input electrical signal. The lower part passes through a half-wave rectifier circuit to obtain the effective value of the AC voltage, which is then connected to the main control circuit.

[0027] like Figure 3 As shown, this is voltage signal processing circuit 3. After the external signal is processed by transformer, filter and other processes, it is transformed into a voltage suitable for voltage sampling. Finally, the signal is processed by introducing a control circuit chip and a power metering chip ATT7022B.

[0028] like Figure 4 The diagram shows the circuit schematic of motor drive circuit 9, which is an IGBT switching transistor drive circuit based on the IR2130 chip. The IR2130 is a high-performance dual-in-line driver with 28 pins. The IR2130 has robust protection functions, including overcurrent, overvoltage, undervoltage, logic identification protection, as well as blocking and indication circuits. Once an overcurrent or bridge arm shoot-through occurs in the external circuit, i.e., the signal sent by the current detection unit is higher than 0.5V, the internal comparator CC quickly flips, causing the fault logic processing unit to output a low level, which in turn makes all outputs of the IR2130 low, ensuring that the six driven MOS transistors are turned off.

[0029] like Figure 5As shown, the over-current protection circuit 6 is a current detection amplification circuit based on voltage comparator LM311. LM311 is a voltage comparator, the input is a continuously changing physical quantity, and the output is a digital quantity. C1 and R2 construct a filter circuit that can filter the input LM311 voltage signal to prevent unnecessary interference, and a light-emitting diode to determine whether a fault has occurred. The working principle is: the circuit voltage information collected by LA28-NP is sent to the No. 3 pin of the LM31 inlet end, and compared with the set voltage Vref. If the motor does not have a fault phenomenon, the No. 7 pin of the LM311 outputs a low level, and the light-emitting diode will not emit light; if the motor fails, the voltage value input by the No. 3 pin is higher than the set voltage Vref, and the No. 7 pin of the LM311 generates a high level signal output. IR2130 has a built-in over-current self-cutting maintenance function, and the voltage output by the current detection circuit is introduced to the 9 pin of IR2130 through a voltage dividing resistor. Assuming that there is a current signal higher than the normal value input externally, that is, the chip measures that the input voltage value is greater than 0.5V, the current comparator inside the chip will immediately act, and at this time the fault output pin will generate a low level signal to block the output, which is used to protect the IGBT.

[0030] As shown in Figure 6 , the over-voltage protection circuit 7 includes an amplification circuit based on operational amplifier TLC2262, an absolute value circuit based on two-stage operational amplifier TLC2262, and a comparison amplification circuit based on LM339, and the amplification circuit, the absolute value circuit, and the comparison amplification circuit are electrically connected in sequence. D1, D2 and operational amplifier TLC2262 are used to take the absolute value of the voltage. If the sampling voltage is greater than the reference voltage, LM339 outputs a low level to send a signal to IR2130 to achieve protection.

[0031] As shown in Figure 7 , it is a logic protection circuit schematic diagram. If the motor suddenly fails when it is working normally, the trigger signals of the power tubes of the upper and lower bridge arms will be effective at the same time, which will cause Figure 4 As shown, V1 and V4 of the inverter (three-phase IGBT inverter circuit) are turned on at the same time, which is the shoot-through phenomenon. After this fault occurs, due to the very small resistance of the loop, a very large current value will flow through the loop circuit, damaging the motor elements. The chip IR2130 is provided with this protection, and the working principle is that if the IGBTs on one bridge arm all receive high-level drive signals, the internal protection circuit will block the two gate drive signals, making them all low, thereby completely avoiding the formation of bridge arm shoot-through. In order to prevent the shoot-through phenomenon from occurring when the motor is powered on and working, a logic protection circuit is added to the control signal as shown in Figure 7The simple logic protection circuit is shown.

[0032] The general working principle of the utility model is:

[0033] The current and voltage signals are sampled by the mutual inductor, and then are connected to the power metering circuit and the main control circuit through the current processing circuit and the voltage processing circuit respectively, the power data of the motor obtained by the power metering circuit is sent to the main control circuit, and the working condition of the motor can be better and more comprehensively mastered.

[0034] The above is the preferred embodiment of the utility model, and it should be pointed out that for ordinary skilled persons in the art, without departing from the principle of the utility model, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the utility model.

Claims

1. A motor protection circuit for a motor protector, characterized in that, The circuit includes a main control circuit (1), a current signal processing circuit (2), a voltage signal processing circuit (3), a power metering circuit (4), a communication circuit (5), an overcurrent protection circuit (6), an overvoltage protection circuit (7), a logic protection circuit (8), a motor drive circuit (9), an inverter (10), and a three-phase motor (11). The main control circuit (1) is electrically connected to the current signal processing circuit (2), the voltage signal processing circuit (3), the power metering circuit (4), the communication circuit (5), the overcurrent protection circuit (6), the overvoltage protection circuit (7), the logic protection circuit (8), and the motor drive circuit (9). The current signal processing circuit (2) and the voltage signal processing circuit (3) are both electrically connected to the power metering circuit (4). The overcurrent protection circuit (6), the overvoltage protection circuit (7), and the logic protection circuit (8) are all electrically connected to the motor drive circuit (9). The output terminal of the motor drive circuit (9) is electrically connected to the inverter (10), and the inverter (10) is electrically connected to the three-phase motor (11).

2. The motor protection circuit of the motor protector according to claim 1, characterized in that, The main control circuit (1) is an ARM processor or a DSP processor.

3. The motor protection circuit of the motor protector according to claim 1, characterized in that, The power metering circuit (4) is a three-phase power metering chip ATT7022B.

4. The motor protection circuit of the motor protector according to claim 1, characterized in that, The communication circuit (5) is an RS485 communication circuit.

5. The motor protection circuit of the motor protector according to claim 1, characterized in that, The overcurrent protection circuit (6) is a current detection and amplification circuit based on the voltage comparator LM311.

6. The motor protection circuit of the motor protector according to claim 1, characterized in that, The overvoltage protection circuit (7) includes an amplifier circuit based on operational amplifier TLC2262, an absolute value taking circuit based on two-stage operational amplifier TLC2262, and a comparison amplifier circuit based on LM339. The amplifier circuit, the absolute value taking circuit, and the comparison amplifier circuit are electrically connected in sequence.

7. The motor protection circuit of the motor protector according to claim 1, characterized in that, The motor drive circuit (9) is an IGBT switch drive circuit based on the IR2130 chip.

8. The motor protection circuit of the motor protector according to claim 1, characterized in that, The inverter (10) is a three-phase IGBT inverter circuit.

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