Asynchronous servo speed regulation device for air compressor

Abstract

The utility model relates to the technical field of air compressor speed regulation, aims to solve the technical problems of high energy consumption, motor overload and mechanical shock caused by the existing air compressor, and discloses an asynchronous servo speed regulation device for an air compressor, which comprises a main control circuit, a rectifying circuit and an inverter circuit, a driving circuit is connected between the main control circuit and the inverter circuit, the driving circuit comprises a PWM controller, the preceding stage of the PWM controller is connected with the main control circuit, the backward stage of the PWM controller is connected with a signal amplification circuit, the inverter circuit comprises an upper power tube and a lower power tube, a collector electrode of the upper power tube inputs direct current, and a collector electrode of the lower power tube inputs direct current. The emitter of the upper power tube is connected with the collector of the lower power tube, the emitter of the lower power tube is grounded, and the emitter of the upper power tube is used for alternating current output. Through the coordinated work of the PWM controller and the signal amplification circuit, the inverter circuit can adjust the output frequency and voltage, and the technical problems of high energy consumption, motor overload and mechanical shock of an existing air compressor are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of air compressor speed regulation, and specifically relates to a device for driving an air compressor motor. Background Art

[0002] Asynchronous servo is a device that uses a vector drive to directly drive an asynchronous motor and has a feedback function. The characteristics of asynchronous servo technology are fast system dynamic response, high cost performance, simple installation, no impact on the production of hydraulic presses in case of failure, low maintenance cost, etc., without affecting the production efficiency of the equipment or the product quality.

[0003] In traditional technologies, air compressors usually use a power supply with a fixed frequency (50Hz), resulting in low energy efficiency and inability to adjust the working state of the air compressor according to actual needs. In addition, due to design limitations, the operation is often not flexible enough and is easily damaged by external factors, affecting the stability and safety of the entire system.

[0004] In traditional technologies, if the motor load is directly hard-started through the bypass AC contactor KM, it will cause an instantaneous large current to flow through the motor, thereby causing problems such as a drop in the grid voltage and fluctuations in the grid frequency, affecting the stability and reliability of the grid. At the same time, the large current during startup may cause the motor coils and windings to be overloaded, increasing the thermal load of the motor, thereby damaging the insulating material and shortening the service life of the motor. Especially for high-power motors, direct startup may cause the motor to be overloaded, damaging the windings or bearings. The instantaneous force and torque mutation during startup may cause mechanical impacts on the motor and related mechanical equipment, damaging components such as transmission devices and bearings, and affecting the reliability and stability of the equipment. Summary of the Utility Model

[0005] The purpose of the utility model is to provide an asynchronous servo speed regulation device for an air compressor to solve the technical problems of motor overload and mechanical impact caused by hard starting of existing air compressors.

[0006] To achieve the above purpose, the specific technical solution of an asynchronous servo speed regulation device for an air compressor of the utility model is as follows:

[0007] An asynchronous servo speed regulation device for an air compressor includes an AC input circuit, a filtering circuit, a voltage sampling circuit, a main control circuit, an inverter circuit, a detection circuit, an input signal circuit, and an output signal circuit;

[0008] The AC input circuit is connected to a rectifier circuit and a switching power supply. The switching power supply powers the input signal circuit, the main control circuit, and the detection circuit. The rectifier circuit, the filter circuit, and the voltage sampling circuit are connected in parallel with the inverter circuit. The inverter circuit is connected to a motor load, and an AC output power supply is connected between the inverter circuit and the motor load. A drive circuit is connected between the main control circuit and the inverter circuit. The main control circuit is connected to a communication interface through an RS485 module. The main control circuit is connected to the output signal circuit and the input signal circuit, and the main control circuit is connected to a protection circuit and peripherals. The detection circuit is connected to the protection circuit and the main control circuit.

[0009] It further includes a current sampling circuit and a temperature sampling circuit. The inverter circuit is connected to the temperature sampling circuit. The current sampling circuit is connected to the parallel combination of the rectifier circuit, the filter circuit, the voltage sampling circuit, and the inverter circuit. The current sampling circuit, the temperature sampling circuit, and the voltage sampling circuit are connected to the detection circuit.

[0010] Further, the drive circuit includes a PWM controller. The front stage of the PWM controller is connected to the main control circuit, and the rear stage of the PWM controller is connected to several groups of signal amplification circuits. The signal amplification circuit includes an upper triode and a lower triode. The emitter of the upper triode is connected to the emitter of the lower triode. The bases of the upper triode and the lower triode are respectively connected to the PWM controller through resistors. The collector of the upper triode inputs a DC voltage, and the collector of the lower triode is grounded. Multiple output ports are provided for the signal amplification circuit.

[0011] Further, the upper triode is an NPN type, and the lower triode is a PNP type.

[0012] Further, the main control circuit includes a control module. The RS485 module has 8 ports. The first port and the fourth port of the RS485 module are respectively connected to the serial port of the control module through serial ports. The second port and the third port of the RS485 module are connected to the main control circuit. The sixth port and the seventh port of the RS485 module are respectively connected to the outside through lines through ports. The eighth port of the RS485 module is a power input terminal, and the eighth port is connected to the power supply through a resistor. The eighth port is grounded through two resistors in sequence. The fifth port of the RS485 module is grounded.

[0013] Further, the inverter circuit includes a plurality of upper power tubes and lower power tubes. The collector of the upper power tube is input with direct current. The emitter of the upper power tube is connected to the collector of the lower power tube, and the emitter of the lower power tube is grounded. The gates of the upper power tube and the lower power tube are respectively connected to the output ports of the signal amplification circuit. The upper power tube and the lower power tube are insulated gate bipolar transistors.

[0014] Further, the inverter circuit includes a plurality of upper diodes and lower diodes. The cathode and anode of the upper diode are respectively connected to the collector and emitter of the upper power tube, and the cathode and anode of the lower diode are respectively connected to the collector and emitter of the lower power tube.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows: By controlling the main control circuit, the present utility model can achieve frequency adjustment. The air compressor adopting the variable frequency speed regulation technology can flexibly adjust the speed according to the actual gas demand, avoiding the reactive power consumption caused by the fixed speed operation of the conventional air compressor.

[0016] In some embodiments, in the case of large load fluctuations, the variable frequency speed regulation air compressor can dynamically adjust the speed according to the actual demand, saving electric energy and solving the technical problems of high energy consumption, motor overload and mechanical shock caused by the hard start of the existing air compressor. Description of the Drawings

[0017] Figure 1 It is a connection relationship diagram of the air compressor and the control circuit provided by the present utility model;

[0018] Figure 2 It is a functional block diagram of the control circuit provided by the present utility model;

[0019] Figure 3 It is the principle of the drive circuit provided by the present utility model Figure 1 ;

[0020] Figure 4 It is the principle of the drive circuit provided by the present utility model Figure 2 ;

[0021] Figure 5 It is a connection relationship diagram of the RS485 module provided by the present utility model.

[0022] In the figure: QF, main circuit breaker; KM, bypass AC contactor; FR, thermal relay; L1, first phase line; L2, second phase line; L3, third phase line; N, neutral line; DC, direct current; VCC2, power supply; VCC1, DC voltage; 1, first port; 4, fourth port; 6, sixth port; 7, seventh port; 8, eighth port; 5, fifth port. Detailed Embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0024] Please refer to Figure 1 and Figure 2 , the present utility model provides an asynchronous servo speed regulation device for an air compressor, which includes an AC input circuit, a filtering circuit, a voltage sampling circuit, a main control circuit, an inverter circuit, a detection circuit, an input signal circuit and an output signal circuit;

[0025] The AC input circuit is connected to a rectifying circuit and a switching power supply. The switching power supply controls the input signal circuit, the main control circuit and the detection circuit. The rectifying circuit, the filtering circuit and the voltage sampling circuit are connected in parallel with the inverter circuit; the inverter circuit is connected to the motor load, and an AC output power supply is connected between the inverter circuit and the motor load; a driving circuit is connected between the main control circuit and the inverter circuit. The main control circuit is connected to a communication interface through an RS485 module. The main control circuit is connected to the output signal circuit and the input signal circuit, and the main control circuit is connected to a protection circuit and peripherals; the detection circuit is connected to the protection circuit and the main control circuit;

[0026] It also includes a current sampling circuit and a temperature sampling circuit; the inverter circuit is connected to the temperature sampling circuit. The current sampling circuit is connected to the parallel body of the rectifying circuit, the filtering circuit, the voltage sampling circuit and the inverter circuit. The current sampling circuit, the temperature sampling circuit and the voltage sampling circuit are connected to the detection circuit;

[0027] Among them, the rectifying circuit is used to convert the external AC input power supply into direct current. The filtering circuit is used to filter out the clutter. The inverter circuit is used to convert the direct current into an AC output power supply. The AC output power supply is used to drive the motor load of the air compressor. The AC input power supply can be a two-phase power supply or a three-phase power supply;

[0028] The voltage sampling circuit is used to sample the direct current voltage. The current sampling circuit is used to detect the direct current. The temperature sampling circuit is used to collect the temperature of the inverter circuit. The three are respectively input to the detection circuit for detection. The detection circuit receives sampling signals such as voltage, current and the temperature of the inverter circuit, and converts them into signals that can be received by the main control circuit, and then is input from the detection circuit to the main control circuit. The main control circuit adjusts the AC output of the inverter circuit through the driving circuit according to parameters such as voltage, current and temperature, so as to control the working state of the motor load;

[0029] The switching power supply is used to provide working power for the corresponding modules in the main control circuit. The switching power supply is powered by the AC input power supply and supplies power to the main control circuit, the detection circuit and the input signal circuit;

[0030] The input signal circuit is used for analog signal input and digital signal input. The analog signal input includes the specific values of temperature, pressure, flow rate, and humidity. The digital signal includes the on / off state of the device and the trigger state of the sensor.

[0031] The output signal circuit is used for alarm output, measurement signal output, and programmable digital output. The measurement signal output converts the measured value of a certain or certain physical quantities in the system into a standard signal output. The programmable digital output is an on / off output signal controlled according to a preset program or condition, which is used to control the on / off of the actuator to achieve automatic control.

[0032] The protection circuit receives the protection instruction input by the main control circuit and implements protection. At the same time, it also directly inputs the detection signal from the detection circuit to protect against emergencies.

[0033] The peripherals are used to achieve human-machine interaction, observe the system status, and perform manual control.

[0034] Please refer to Figure 3 , where Q22, Q20, and Q18 are all upper triodes, and Q23, Q21, and Q19 are all lower triodes. The drive circuit includes a PWM controller. The front stage of the PWM controller is connected to the main control circuit. Under the control of the main control circuit, the PWM controller is used to generate a PWM waveform with a dynamic frequency. The rear stage of the PWM controller is connected to several groups of signal amplification circuits. The signal amplification circuit includes an upper triode and a lower triode. The emitter of the upper triode is connected to the emitter of the lower triode. The bases of the upper triode and the lower triode are respectively connected to the PWM controller through resistors. The collector of the upper triode inputs the DC voltage VCC1, and the collector of the lower triode is grounded.

[0035] The PWM waveform output terminal of the PWM controller is grounded through the resistor R44. Connecting the resistor R44 to the ground can effectively eliminate interference signals, ensure the stability and accuracy of the output signal, and make the output signal within the specified range to avoid exceeding the expected range to provide protection for the subsequent circuit.

[0036] Please refer to Figure 4, OUT1, OUT2, OUT3, OUT4, OUT5, and OUT6 are all output ports, Q33, Q29, and Q24 are all upper power transistors, Q35, Q33, and Q27 are all lower power transistors, and D6, D7, D8, D9, D10, and D11 are all diodes; the inverter circuit includes multiple upper power transistors and lower power transistors. The collector of the upper power transistor is input with direct current DC, the emitter of the upper power transistor is connected to the collector of the lower power transistor, the emitter of the lower power transistor is grounded, and the gates of the upper power transistor and the lower power transistor are respectively connected to the output ports of the signal amplification circuit; the upper power transistor and the lower power transistor are insulated gate bipolar transistors. The insulated gate bipolar transistor has a low on-voltage drop, enabling the upper power transistor and the lower power transistor to operate with low power loss. By controlling the gate voltage, the conduction and cutoff of the upper power transistor and the lower power transistor can be precisely controlled, thereby achieving precise control of the current;

[0037] The node of the emitter of the upper power transistor and the collector of the lower power transistor is the AC output node. By setting two or three sets of circuits of the upper power transistor and the lower power transistor, a two-phase or three-phase AC output power supply can be formed;

[0038] The inverter circuit includes multiple upper diodes and lower diodes. The cathode and anode of the upper diode are respectively connected to the collector and emitter of the upper power transistor, and the cathode and anode of the lower diode are respectively connected to the collector and emitter of the lower power transistor.

[0039] Please refer to Figure 5 , RS485_A and RS485_B are both through ports, and RXD_1 and TXD_1 are both serial ports; the main control circuit includes a control module. The RS485 module has 8 ports. The first port 1 and the fourth port 4 of the RS485 module are respectively connected to the serial port of the control module through the serial ports RXD_1 and TXD_1. The second port and the third port of the RS485 module are connected to the main control circuit. The sixth port 6 and the seventh port 7 of the RS485 module are respectively connected to the outside through the ports RS485_A and RS485_B through lines. The eighth port 8 of the RS485 module is the power input terminal, and the eighth port 8 is connected to the power supply VCC2 through a resistor; the eighth port 8 is grounded through two resistors in sequence; the fifth port 5 of the RS485 module is grounded.

[0040] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An asynchronous servo speed regulation device for an air compressor, characterized in that: It includes an AC input circuit, a filtering circuit, a voltage sampling circuit, a main control circuit, an inverter circuit, a detection circuit, an input signal circuit, and an output signal circuit; The AC input circuit is connected to a rectifying circuit and a switching power supply. The switching power supply supplies power to the input signal circuit, the main control circuit, and the detection circuit. The rectifying circuit, the filtering circuit, and the voltage sampling circuit are connected in parallel with the inverter circuit. The inverter circuit is connected to a motor load, and an AC output power supply is connected between the inverter circuit and the motor load. A driving circuit is connected between the main control circuit and the inverter circuit. The main control circuit is connected to a communication interface through an RS485 module. The main control circuit is connected to the output signal circuit and the input signal circuit, and the main control circuit is connected to a protection circuit and peripherals. The detection circuit is connected to the protection circuit and the main control circuit; It further includes a current sampling circuit and a temperature sampling circuit. The inverter circuit is connected to the temperature sampling circuit. The current sampling circuit is connected to the parallel combination of the rectifying circuit, the filtering circuit, the voltage sampling circuit, and the inverter circuit. The current sampling circuit, the temperature sampling circuit, and the voltage sampling circuit are connected to the detection circuit.

2. The asynchronous servo speed regulation device for an air compressor according to claim 1, wherein: The driving circuit includes a PWM controller. The front stage of the PWM controller is connected to the main control circuit, and the rear stage of the PWM controller is connected to several groups of signal amplification circuits. The signal amplification circuit includes an upper triode and a lower triode. The emitter of the upper triode is connected to the emitter of the lower triode. The bases of the upper triode and the lower triode are respectively connected to the PWM controller through resistors. The collector of the upper triode inputs a DC voltage (VCC1), and the collector of the lower triode is grounded. The signal amplification circuit is provided with multiple output ports.

3. The asynchronous servo speed regulation device for an air compressor according to claim 2, characterized in that: The upper triode is of NPN type, and the lower triode is of PNP type.

4. The asynchronous servo speed regulation device for an air compressor according to claim 1, characterized in that: The main control circuit includes a control module. The RS485 module has 8 ports. The first port (1) and the fourth port (4) of the RS485 module are respectively connected to the serial port of the control module through serial ports (RXD_1, TXD_1). The second port and the third port of the RS485 module are connected to the main control circuit. The sixth port (6) and the seventh port (7) of the RS485 module are respectively connected to the outside through lines through ports (RS485_A, RS485_B). The eighth port (8) of the RS485 module is the power input terminal, and the eighth port (8) is connected to the power supply (VCC2) through a resistor. The eighth port (8) is grounded through two resistors in sequence. The fifth port (5) of the RS485 module is grounded.

5. The asynchronous servo speed regulation device for an air compressor according to claim 1, characterized in that: The inverter circuit includes multiple upper power tubes and lower power tubes. The collector of the upper power tube inputs direct current (DC). The emitter of the upper power tube is connected to the collector of the lower power tube. The emitter of the lower power tube is grounded. The gates of the upper power tube and the lower power tube are respectively connected to the output ports of the signal amplification circuit. The upper power tube and the lower power tube are insulated gate bipolar transistors.

6. The asynchronous servo speed regulation device for an air compressor according to claim 5, characterized in that: The inverter circuit includes a plurality of upper diodes and lower diodes. The cathodes and anodes of the upper diodes are respectively connected to the collectors and emitters of the upper power transistors, and the cathodes and anodes of the lower diodes are respectively connected to the collectors and emitters of the lower power transistors.

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