JPH0584000A - Motor driver - Google Patents

Abstract

PURPOSE:To prevent step-out by applying the difference between the voltage phase of a permanent magnet motor and the phase of rotor, as a current reference correction signal, onto a current control system for controlling the current of a load commutation type inverter based on a current reference signal outputted from a speed control circuit for controlling the speed of the permanent magnet motor and the output current from a converter. CONSTITUTION:A speed control circuit 13 performs speed control based on a speed reference signal for a permanent magnet motor 6 and a speed feedback signal 11a of the permanent magnet motor 6 obtained by passing the output of a position detector 8 through a speed detecting circuit 11, and the output from the speed control circuit 13 is employed as a current reference signal 13a for a load commutation type inverter 3. When a current control circuit 14 performs current control based on a current reference signal 13a and a current feedback signal 17 of the load commutation type inverter 3, the difference of internal phase angle between rated rotation and actual rotation of the permanent magnet motor 6 is converted through a phase comparing circuit 10 into a current reference correction signal 16 and applied onto a current control system thus performing incremental/decremental correction of energy at the time of abrupt load variation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor drive device for driving an electric motor to rotate at high speed with a high frequency power source.

[0002]

2. Description of the Related Art The technology for driving an electric motor at high speed with a power supply of a frequency higher than the commercial power supply frequency has been revolutionized with the progress of conversion equipment. The motor drive was not realized. One of the causes is that conventional induction motors and synchronous motors have problems in mechanical strength, vibration, etc., and the motors have not been realized.

[0003]

Recently, with the development of technologies for permanent magnets and magnetic bearings, the feasibility of permanent magnet synchronous motors of large capacity and ultra-high speed is increasing. However,
A large-capacity converter capable of high-frequency sine wave output for driving this permanent magnet synchronous motor has not yet been realized.

An object of the present invention is to provide an electric motor drive device for driving a large-capacity, high-speed rotating permanent magnet electric motor using a conventional converter.

[0005]

SUMMARY OF THE INVENTION The present invention uses a thyristor motor operated by a load commutation type inverter, a permanent magnet generator driven by being directly connected to the thyristor motor, and power generated by the permanent magnet generator. A permanent magnet electric motor that is driven and drives a load machine, a position detector that measures the rotation speed of this permanent magnet electric motor, and a rotation speed detection signal that is connected to this position detector to detect the rotation speed of the permanent magnet electric motor and output a speed feedback signal. Of the speed detection circuit, a speed control circuit that outputs a current reference signal of the load commutation inverter from the speed feedback signal and a predetermined speed reference signal, and the output power of the permanent magnet generator and the output signal of the position detector By comparing the phases, the current reference correction signal of the load commutation inverter and the power from the inverter control circuit controlling the load commutation inverter are compared. A motor driving device comprising; and a current control circuit for outputting a phase reference signal of the inverter control circuit and a feedback signal.

[0006]

According to the motor drive device of the present invention, a permanent magnet motor is directly connected to a thyristor motor operated by a load commutation inverter to drive a permanent magnet generator, and the load machine is driven by the power generated by the permanent magnet generator. Run, measure the rotation speed of the permanent magnet motor, detect the rotation speed of the permanent magnet motor, output a speed feedback signal, and use the speed feedback signal and a predetermined speed reference signal to reference the current of the load commutation inverter. It outputs a signal, compares the output power of the permanent magnet generator and the phase of the output signal of the position detector and outputs the current reference correction signal of the load commutation type inverter, and outputs the current reference signal, the current reference correction signal and the load. Outputs the phase reference signal of the inverter control circuit from the current feedback signal from the inverter control circuit that controls the commutation inverter, and Performing current control of the commutated inverter.

[0007]

EXAMPLE An example of the present invention will be described below. Figure 1
The thyristor motor 4 driven by the load commutation type inverter 3, the permanent magnet generator 5 driven directly by the thyristor motor 4, and the permanent magnet generator 5 driven by the power generated by the permanent magnet generator 5 to drive the load machine 7. Magnet motor 6
A position detector 8 for measuring the rotation speed of the permanent magnet motor 6; a speed detection circuit 11 connected to the position detector 8 for detecting the rotation speed of the permanent magnet motor 6 and outputting a speed feedback signal 11a; A speed control circuit 13 that outputs a current reference signal 13a of the load commutation inverter 3 from the feedback signal 11a and a predetermined speed reference signal 12, the output power of the permanent magnet generator 5 and the output signal of the position detector 8. And a phase comparison circuit 10 for comparing the phase with and outputting a current reference correction signal 16 of the load commutation type inverter 3, and a current reference signal.
13a, the current reference correction signal 16, and the current feedback signal 17 from the inverter control circuit 15 that controls the load commutation type inverter 3 from the phase reference signal 14 of the inverter control circuit 15.
1 shows a motor drive device including a current control circuit 14 that outputs a. That is, the MG set including the thyristor motor 4 and the permanent magnet generator 5, and the load commutation inverter 3 that drives the thyristor motor 4 at a variable speed.
In the permanent magnet motor 6 driven by the output of the permanent magnet generator 5, a speed control for controlling the speed of the permanent magnet motor 6 by the speed reference signal 12 of the permanent magnet motor 6 and the speed feedback signal 11a of the permanent magnet motor 6. The circuit 13, the current reference signal 13a which is the output of the speed control circuit 13, and the current feedback signal 17 of the output current of the load commutation inverter 3
And current control for controlling the output current of the load commutation inverter 3 by the current reference correction signal 16 which is the output of the phase comparison circuit 10 for detecting the voltage phase of the permanent magnet motor 6 and the phase difference of the rotor of the permanent magnet motor 6. A motor drive device comprising a circuit 14 and an inverter control circuit 15 for controlling the load commutation type inverter 3 by a phase control signal 14a output from the current control circuit 14 and a speed reference signal 12 of the permanent magnet motor 6. , MG according to the frequency required by the permanent magnet motor 6
By selecting the number of poles of the set thyristor motor 4 and the permanent magnet generator 5 and driving the thyristor motor 4 at a variable speed according to the speed of the permanent magnet motor 6, the output of the permanent magnet generator 5 is used to output the permanent magnet motor. Drive 6

At this time, the current control signal 13a which is the output of the speed control circuit 13 for controlling the speed of the permanent magnet motor 6 and the output current of the converter are used for the current control for controlling the current of the load commutation inverter 3. By adding the difference between the voltage phase of the magnet motor 6 and the phase of the rotor as the current reference correction signal 16, the permanent magnet motor 6 is prevented from being out of step when the load changes, and the permanent magnet motor 6 is stably operated.

That is, in FIG. 1, 1 is a switch, 2 is a transformer, 3 is a load commutation inverter, 4 is a thyristor motor driven by the load commutation type inverter 3, and drives a permanent magnet generator 5. This constitutes an MG set. The permanent magnet motor 6 is driven by the output of the permanent magnet generator 5 and drives the load 7. Reference numeral 8 is a position detector,
The position of the rotor of the permanent magnet motor 6 is detected. 9 is a transformer, 10 is a phase comparison circuit, 11 is a speed detection circuit, 12 is a speed reference signal of a permanent magnet motor, 13 is a speed control circuit, 14 is a current control circuit, and 15 is a phase control which is an output of the current control circuit. This is a control circuit of the load commutation inverter that controls the load commutation inverter 3 from the signal and the speed reference signal 12. First, the main circuit configuration will be described.

In order for the permanent magnet motor 6 to operate at 20000 rpm, if the permanent magnet motor 6 is a two-pole machine, it will be approximately 333.3 Hz.
Power supply is required. When using the MG set to make this power source, for example, it is sufficient to operate the generator with an electric motor at 333 rpm with a generator having 12 poles, but with a normal generator a solid rotor is used for 3000 rpm or more. It will be a two-pole machine, and it will be difficult to manufacture a generator with 12 poles and 3000 rpm or more due to mechanical strength constraints. However, it is easy to construct a multi-pole machine by using permanent magnets, and the permanent magnet generator 5 is adopted as the generator.

On the electric motor side of the MG set, a load commutation type inverter 3 is provided for variable speed driving so that the permanent magnet generator 5 can output a frequency corresponding to a desired speed of the permanent magnet electric motor 6. It is used as a thyristor motor 4.

With this main circuit configuration, the permanent magnet motor 6
Can be driven by a high frequency power source with sine wave output.

Next, the control circuit will be described.

Since the permanent magnet motor 6 and the permanent magnet generator 5 both use permanent magnets for the field, the magnetic flux of the field cannot be adjusted as in the conventional synchronous machine, and the field is fixed. . Therefore, the load commutation type inverter 3 simply drives the motor 4
The speed of the permanent magnet electric motor, that is, the speed of the permanent magnet electric motor and the output of the thyristor motor 4 are not controlled, the output of the permanent magnet electric motor 6 cannot be immediately controlled when the load 7 changes. There is a risk that 6 will be out of step and the operation cannot be continued, and even if it is not out of step, the operation becomes unstable.

Therefore, the control circuit is constructed as follows.

First, the speed reference signal of the permanent magnet motor 6 and the output of the position detector 8 attached to the permanent magnet motor 6 are supplied to the speed control circuit 13 by the speed feedback signal 11a of the permanent magnet motor obtained through the speed detection circuit 11. Then, the output of the speed control circuit 13 is used as the current reference signal 13a of the load commutation type inverter 3.

Next, the current control circuit 14 uses the current reference signal and the current feedback signal 17 of the load commutation type inverter to make the following corrections when performing current control. The difference between the phase of the voltage of the permanent magnet motor 6 and the phase of the rotor of the permanent magnet motor 6 detected by the position detector 8 corresponds to the internal phase difference angle of the permanent magnet motor 6, and the energy required by the load machine 7 is If it suddenly increases, the internal phase difference angle increases and 90
When the angle exceeds °, the permanent magnet motor 6 goes out of step. Therefore, if the internal phase difference angle during the rated operation of the permanent magnet motor is δ and the internal phase difference angle during the actual operation is δ ', the difference δ'-δ
Is converted into a current reference correction signal 16 by the phase comparison circuit 10 and added to the current control, so that the energy increase / decrease at the time of sudden load change is corrected. By the phase reference signal 14a which is the output of the current control circuit 14 and the speed reference signal 12, the load commutation type inverter 3 is controlled by the load commutation type inverter control circuit 15.
It controls and controls the thyristor motor 4.

As described above, the thyristor motor 4 is operated at a speed and an output at which the permanent magnet generator 5 can output the frequency and output required for the permanent magnet motor 6 to operate at a desired speed. Further, when the required energy of the load machine 7 suddenly changes, the output of the load commutation type inverter is changed according to the load change by the current reference correction signal, and the internal phase difference angle of the permanent magnet motor 6 is controlled to be kept constant. It is possible to prevent out-of-step of the permanent magnet motor 6 and continue stable operation.

In the above embodiment, the thyristor motor is used for the electric motor of the MG set and the load commutation type inverter is used for the converter. However, another motor is used for the MG set and the converter for controlling the same. It is clear that the present invention can be applied even if a variable speed drive system is used.

It is also clear that various combinations of generator and motor speed of the MG set can be selected according to the frequency required for the permanent magnet motor.

[0021]

According to the present invention, it is possible to provide an electric motor drive device for stably operating a permanent magnet electric motor with a high frequency current of a sine wave.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an electric motor drive device showing an embodiment of the present invention.

[Explanation of Codes] 3 ... Load commutation type inverter 4 ... Thyristor motor 5 ... Permanent magnet generator 6 ... Permanent magnet motor 8 ... Position detector 10 ... Phase comparison circuit 11 ... Speed detection circuit 13 ... Speed control circuit 14 ... Current Control circuit

Claims (1)

[Claims] 1. A thyristor motor operated by a load commutation type inverter, a permanent magnet generator driven by being directly connected to the thyristor motor, and a load machine driven by electric power generated by the permanent magnet generator. A permanent magnet motor, a position detector that measures the rotation speed of the permanent magnet motor, a speed detection circuit that is connected to the position detector to detect the rotation speed of the permanent magnet motor, and output a speed feedback signal; A speed control circuit that outputs a current reference signal of the load commutation type inverter from a speed feedback signal and a predetermined speed reference signal, and the phase of the output power of the permanent magnet generator and the output signal of the position detector A phase comparison circuit for comparing and outputting a current reference correction signal of the load commutation type inverter, the current reference signal and the current reference compensation signal. A motor drive device comprising: a positive signal and a current control circuit that outputs a phase reference signal of the inverter control circuit from a current feedback signal from an inverter control circuit that controls the load commutation type inverter.