CN201290092Y - Pressure-regulating and energy-saving controller for asynchronous motor - Google Patents

Abstract

The utility model relates to an asynchronous motor voltage regulating and energy saving controller. It is suitable for frequency conversion drive system in industrial and agricultural production. The known energy-saving starting controllers for asynchronous motors mostly output the trigger pulse of the thyristor based on the zero-crossing point of the voltage signal of the power supply, and adjust the terminal voltage of the motor to achieve the purpose of energy saving. Experimental research shows that when using this voltage regulation method to perform light-load soft start and voltage regulation and energy-saving control of the motor, the phenomenon of motor current and speed oscillation is easy to occur. The utility model is composed of a trigger pulse drive circuit, a current synchronous signal detection circuit, a power supply voltage synchronous signal detection circuit, a controller power supply and a fault detection circuit, a control chip, and a power thyristor. The utility model has the functions of avoiding the vibration phenomenon of the motor during the voltage regulation process of the voltage synchronous signal, and adopts the power factor as the voltage regulation energy-saving control signal, so that the overall circuit structure is relatively simple, and it is easy to implement and operate.

Description

Asynchronous Motor Voltage Regulating Energy Saving Controller

technical field

The utility model relates to an asynchronous motor voltage regulating energy-saving controller, which is suitable for frequency conversion transmission systems in industrial and agricultural production. It belongs to the field of electrician and motor.

Background technique

The known energy-saving starting controllers for asynchronous motors mostly output the trigger pulse of the thyristor based on the zero-crossing point of the voltage signal of the power supply, and adjust the terminal voltage of the motor to achieve the purpose of energy saving. Experimental research shows that when using this voltage regulation method to perform light-load soft start and voltage regulation and energy-saving control of the motor, the phenomenon of motor current and speed oscillation is easy to occur. Thereby, people urgently hope to have a kind of energy-saving controller that can overcome above-mentioned defect come out.

Contents of the invention

In order to realize the purpose of stable soft start and light-load voltage regulation and energy-saving operation of an asynchronous motor with a simple circuit structure and reasonable control amount, the utility model provides an asynchronous motor voltage regulation and energy-saving controller.

In order to achieve the above object, the technical solution of the utility model is composed of a trigger pulse drive circuit, a current synchronous signal detection circuit, a power supply voltage synchronous signal detection circuit, a controller power supply and a fault detection circuit, a control chip, and a power thyristor. It is characterized in that power thyristors are connected in series between the three-phase power supply and the motor of the asynchronous motor, and the current synchronous signal detection circuit is connected in parallel with the power thyristors; the input terminals of the controller power supply and the fault detection circuit are connected with phase A and phase B of the power supply, and the output terminals It is connected with the control chip; the input terminal of the power supply voltage synchronous signal detection circuit is connected with the three-phase power supply, and its signal is output to the control chip; the signal of the current synchronous signal detection circuit is output to the control chip; the signal of the control chip is output to the trigger pulse drive circuit, The trigger pulse drive circuit is connected with the two trigger terminals of the power thyristor.

The beneficial effects of the utility model are: avoiding motor oscillation during voltage synchronous signal regulation, adopting power factor as voltage regulation and energy-saving control signal makes overall circuit structure relatively simple, easy to implement and operate.

Description of drawings

Accompanying drawing 1 is a structural diagram of the present invention

Accompanying drawing 2 is the circuit diagram of current synchronous signal detection circuit among the present invention

Accompanying drawing 3 is the circuit diagram of trigger pulse driving circuit in the present invention

Accompanying drawing 4 is the circuit diagram of power supply voltage synchronous signal detection circuit among the present invention

In the accompanying drawings, 1, 3, 5 trigger pulse driving circuit, 2, 4, 6 current synchronous signal detection circuit, 7 power supply voltage synchronous signal detection circuit, 8 controller power supply and fault detection circuit, 9 control chip, 10, 11, 12 power thyristors, 13 asynchronous motor motors.

Detailed ways

Connect the wires by the mark on the utility model, the controller power supply and the fault detection circuit 8 provide power supply for the present invention after electrification. Before the thyristor is turned on, the three-phase power supply forms a loop through the RC absorption loops in the current synchronous signal detection circuits 2, 4, and 6. At this time, the signals output by the current synchronous signal detection circuits 2, 4, and 6 are zero-crossing signals of the three-phase voltage. This signal is used to judge the phase sequence of the power supply. The control chip 9 judges the circuit measured by the power supply voltage synchronous signal detection circuit 7 according to the measured signal to be phase A, takes the phase A voltage synchronous signal as a reference, and sends A, The trigger pulses of the power thyristors 10, 11, 12 in the B and C three-phase circuits make the motor energized, once there is current flowing through the power thyristors 10, 11, 12, the signals detected by the current synchronous signal detection circuits 2, 4, 6 will be It is the current synchronous signal. At this time, the reference standard is changed to the current synchronous signal, and the trigger pulse signal of each phase is adjusted to gradually increase the motor voltage to realize the soft start of the motor.

After the motor runs stably, in order to keep the current synchronization signal from disappearing, the power thyristors 10, 11, 12 cannot be fully turned on. The time difference between the A-phase current zero-crossing signal detected by the current synchronous signal detection circuit 2 and the A-phase voltage zero-crossing signal detected by the power supply voltage synchronous signal detection circuit 7 is the time parameter of the measurable power factor angle of the asynchronous motor. 9 Converted to power factor parameters, used for light-load voltage regulation and energy-saving control parameters. Since the current of the motor after voltage regulation is a non-sinusoidal waveform, this value is not the actual power factor of the motor, but it reflects the size of the power factor and the load condition. If the control chip 9 judges that the motor is in a light-load operating condition according to the power factor, the firing angle of the thyristor is increased by triggering the pulse drive circuits 1, 3, and 5, and the voltage of the motor is reduced to ensure that the power factor is within an appropriate range. Maintain the firing angle, where the input voltage matches the load. If the load increases at this time, the control chip 9 will reduce the firing angle of the thyristor through the trigger pulse driving circuits 1, 3, and 5 according to the change of the power factor, so that the voltage of the motor increases until the power factor is in a suitable range. Keep the firing angle unchanged, at this time, the motor runs at the matching voltage value of the load, so as to ensure that the motor works at the approximate best matching voltage in the entire load range, and achieve the purpose of dynamic energy saving.

The power supply voltage synchronous signal detection circuit 7 and the controller power supply and fault detection circuit 8 can be combined to determine whether there are protections such as phase loss and motor overheating.

Claims (1)

1, a kind of voltage-regulating and energy-saving controller for asynchronous motor is characterized in that the power scr of connecting respectively between the motor of three phase mains and asynchronous motor, and the current synchronous signal testing circuit is in parallel with power scr; The input of controller power source and failure detector circuit and power supply A are mutually, B is connected, and its output links to each other with control chip; The input of supply voltage synchronization signal detection circuit is connected with three phase mains, and its signal outputs to control chip; The signal of current synchronous signal testing circuit outputs to control chip; The signal of control chip outputs to the trigger impulse drive circuit, and the trigger impulse drive circuit is connected with two trigger ends of power scr.

Images