JP6032809B2 - Control device for permanent magnet synchronous motor - Google Patents

Description

  The present invention relates to a controller for a permanent magnet synchronous motor that controls parallel operation of a plurality of permanent magnet synchronous motors.

  Induction motors are highly reliable, have a simple structure, and are inexpensive. Therefore, induction motors are widely used in general industrial machines such as cranes. The total amount of power capacity is the largest.

  FIG. 8 shows a conventional drive system in which a plurality of induction motors (IM) 103a to 103c are driven by a plurality of inverters 101a to 101c. In a system for driving a plurality of electric motors such as driving of a fan and a blower, as shown in FIG. 9, a plurality of induction motors 103a to 103c are formed by one inverter 101d from the viewpoint of downsizing, weight reduction, and cost reduction of the apparatus. The system which drives is used.

  In the induction motor, the reason why the plurality of induction motors 103a to 103c can be driven by one inverter 101d is that the induction motor has a slip, and the slip is obtained by this slip. Due to this characteristic, when induction motors are operated in parallel, each induction motor converges to the same rotational speed due to slippage.

  On the other hand, permanent magnet synchronous motors are widely used from the viewpoint of energy saving in recent years because they are not limited to capacity ranges but are highly efficient and small in size as compared with induction motors.

JP 2010-22184 A

  However, when the parallel operation technique in the induction motor is applied to the permanent magnet synchronous motor, the permanent magnet synchronous motor cannot be operated in parallel by one inverter because of the principle and structure of the permanent magnet synchronous motor. That is, in the permanent magnet synchronous motor, the current must be controlled in accordance with the magnetic pole position, so that the permanent magnet synchronous motor cannot be operated in parallel with one inverter.

  Further, when the permanent magnet synchronous motor is essentially driven by V (voltage) / f (frequency) control, load torque vibration is generated due to resonance of the moment of inertia with the synchronous reactance. This load torque vibration appears as load angle vibration and torque rotation speed vibration, which are called turbulence. This load angle vibration causes the load torque to exceed the escape torque, resulting in step-out. For this reason, in order to operate a plurality of permanent magnet synchronous motors in parallel, it is important how to suppress torque vibration.

  An object of the present invention is to provide a control device for a permanent magnet synchronous motor that can drive a plurality of permanent magnet synchronous motors and suppress torque vibration.

  The controller for a permanent magnet synchronous motor of the present invention is connected to a plurality of permanent magnet synchronous motors each having a main winding and an auxiliary winding, and the main windings included in each of the plurality of permanent magnet synchronous motors. The main inverter is provided corresponding to the plurality of permanent magnet synchronous motors, connected to the auxiliary winding of the permanent magnet synchronous motor, and the load angle of the permanent magnet synchronous motor via the auxiliary winding. And a plurality of auxiliary inverters for supplying a current for generating torque that cancels torque vibration caused by fluctuations caused by fluctuations to the permanent magnet synchronous motor.

  According to the present invention, a plurality of permanent magnet synchronous motors can be driven by the main inverter, and a torque that cancels torque vibrations caused by fluctuations in the load angle of the permanent magnet synchronous motor via the auxiliary windings can be driven by the plurality of auxiliary inverters. Since the current to be generated flows through the permanent magnet synchronous motor, the vibration torque can be canceled and the torque vibration can be suppressed.

1 is a configuration block diagram of a controller for a permanent magnet synchronous motor according to a first embodiment of the present invention. It is a detailed block diagram of the main inverter control part and auxiliary inverter control part which were provided in the control apparatus of the permanent magnet synchronous motor of Example 1 of this invention. It is a figure which shows the damping control block by the damping control part provided in the auxiliary inverter control part shown in FIG. It is a figure which shows the simulation result at the time of the motor acceleration before damping control application at the time of a single operation. It is a figure which shows the simulation result at the time of the motor acceleration after the damping control application at the time of a single operation. It is a figure which shows simulation conditions. It is a figure which shows the simulation result at the time of the parallel operation to which damping control is applied. It is a block diagram showing a conventional drive system that drives a plurality of induction motors with a plurality of inverters. It is a block diagram which shows the conventional drive system which drives several induction motors with one inverter.

  Hereinafter, a control device for a permanent magnet synchronous motor according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a control device for a permanent magnet synchronous motor according to a first embodiment of the present invention. The control device for a permanent magnet synchronous motor according to the first embodiment drives n permanent magnet synchronous motors by using one main inverter and n (an integer of n ≧ 2) auxiliary inverters. . In the first embodiment shown in FIG. 1, an example in which n is three is shown. n is not limited to 3.

  The control device for the permanent magnet synchronous motor shown in FIG. 1 includes one main inverter 1, auxiliary inverters 3a to 3c, and three permanent magnet synchronous motors 5a to 5c.

  The permanent magnet synchronous motor 5a has a main winding 7a connected to the main inverter 1 and an auxiliary winding 9a for damping control connected to the auxiliary inverter 3a. The permanent magnet synchronous motor 5b has a main winding 7b connected to the main inverter 1 and an auxiliary winding 9b for damping control connected to the auxiliary inverter 3b. The permanent magnet synchronous motor 5c has a main winding 7c connected to the main inverter 1 and an auxiliary winding 9c for damping control connected to the auxiliary inverter 3c.

  The main inverter 1 has a large capacity, performs a group operation of the plurality of permanent magnet synchronous motors 5a to 5c, and operates the plurality of permanent magnet synchronous motors 5a to 5c in parallel by V / f control. Since V / f control does not require a sensor and drives a permanent magnet synchronous motor in an open loop, parallel operation of a plurality of permanent magnet synchronous motors 5a to 5c becomes easier than vector control.

  The auxiliary inverters 3a to 3c cancel the vibration torque caused by the turbulence by causing the permanent magnet synchronous motors 5a to 5c to pass a current that generates torque that cancels the torque vibration caused by the turbulence via the auxiliary windings 9a to 9c. Specifically, the auxiliary inverters 3a to 3c individually perform current control by vector control, operate the speed controller as a damping controller, that is, perform damping control via the auxiliary windings 9a to 9c, Suppresses turbulence.

  The auxiliary windings 9a to 9c are designed to have a sufficiently small rated capacity with respect to the main windings 7a to 7c, and the auxiliary inverters 3a to 3c are designed to have a sufficiently small rated capacity with respect to the main inverter 1. Yes.

  Therefore, the control device for the permanent magnet synchronous motor according to the first embodiment can perform parallel operation without causing irregularities in the output torque and the rotation speed.

  In addition, in order that the auxiliary inverters 3a-3c accompanying each permanent magnet synchronous motor 5a-5c suppress the turbulence which arises in each permanent magnet synchronous motor 5a-5c, three or more permanent magnet synchronous motors are operated in parallel. However, the system can be stabilized by the same system.

  For this reason, the control device for the permanent magnet synchronous motor according to the first embodiment has a plurality of permanent magnets in one main inverter 1 having a large capacity, as compared with a system in which a medium capacity inverter is connected to one permanent magnet synchronous motor. By connecting the synchronous motors 5a to 5c and connecting the small capacity auxiliary inverters 3a to 3c, the cost of the system can be reduced.

  FIG. 2 is a detailed block diagram of the main inverter control unit and the auxiliary inverter control unit provided in the control device for the permanent magnet synchronous motor according to the first embodiment of the present invention.

The main inverter control unit 11, a main inverter 1 and controls V / f, the speed command omega ^Z into a command voltage _v γδ ^ж by the f / V converting unit 111, the differential speed command ^ω ж (1 / s ) to determine the indication angle theta _{the ??,} converts command voltage v _{the ??} ^Z and instructs the angle theta of _{the ??} by the ?? / 3 [phi] conversion unit 115 of the 3-phase u-phase v-phase and w-phase three-phase command voltages vum, VWM, the vvm Thus, the three-phase command voltages vum, vwm, vvm are supplied to the main inverter 1.

  The pulse generator (PS) 15 generates a pulse according to the magnetic pole position and the rotational angular velocity of the permanent magnet synchronous motor 5, and converts the magnetic pole position detection value θ corresponding to the generated pulse to the dq / uvw conversion unit 134 and the dq / uvw. The data is output to the conversion unit 149 and the rotational angular velocity ω is output to the adder 131.

The auxiliary inverter control unit 13 performs vector control of the auxiliary inverter 3 using the two axes of the d axis and the q axis. As for the coordinate axis of each auxiliary inverter 3, the d-axis is made to coincide with the direction of the magnetic flux vector, as in normal vector control. There is a method of controlling the d-axis current command value id ^ж so as to realize the maximum efficiency operation, but here, for simplicity, the d-axis current command value id ^{ж is set} to zero. The q-axis current command value iq ^ж gives a counter in the reverse direction according to the variation of the magnetic pole position in order to suppress torque vibration.

FIG. 3 is a diagram showing a damping control block by the damping control unit provided in the auxiliary inverter control unit shown in FIG. In the damping control shown in FIG. 3A, an adder 19 obtains a difference δ between the magnetic pole position command θ ^ж and the detected magnetic pole position value θ, and uses the difference δ as a transfer function 21 having a first-order lag differential element and an integral element. To pseudo-differentiate the magnetic pole position. Further, the fluctuation of the magnetic pole position is multiplied by a proportional gain Kd to obtain a d-axis current command value iq ^ж .

  However, since the damping control method shown in FIG. 3A differentiates the position information, there is a problem that it is easily affected by noise, and there is a band limitation due to pseudo differentiation.

Therefore, in the auxiliary inverter control unit 13 shown in FIG. 2, paying attention to the fact that the derivative of the magnetic pole position is the speed, as shown in FIG. 3B and the auxiliary inverter control unit 13, the adder is used using the speed information. 131 subtracts the rotational angular velocity ω from the pulse generator (PS) 15 from the angular velocity command ω ^ж and outputs the obtained deviation Δω to the damping control unit 133.

The damping control unit 133 multiplies the deviation Δω from the adder 131 by the damping gain Kd to obtain a q-axis current command value iq ^ж . Here, the damping control has the same configuration as that of the speed controller (ACR). However, by using a proportional controller as the controller, only the fluctuation is compensated for the speed command set by the V / f control. It works in the form of

  Here, for simplicity, it is assumed that the magnetic flux information is provided with a sensor, but it can also be estimated using a sensorless vector control technique.

  The current detector 17 detects the three-phase currents iu, iw, iv flowing through the auxiliary inverter 3 and outputs the detected current to the dq / uvw conversion unit 134. The dq / uvw conversion unit 134 converts the three-phase currents iu, iw, iv into a d-axis current detection value id and a q-axis current detection value iq, outputs the d-axis current detection value id to the adder 137, and outputs the q-axis The detected current value iq is output to the adder 135.

The adder 137 subtracts the d-axis current detection value id from the d-axis current command value id ^ж and outputs a subtraction output to the ACR 141 and the decoupling control unit 139. The adder 135 subtracts the q-axis current detection value iq from the q-axis current command value iq ^ж and outputs a subtraction output to the ACR 143 and the decoupling control unit 139.

The adder 145 subtracts the output of the decoupling control unit 139 from the output of the ACR 141 and outputs the subtraction output to the dq / uvw conversion unit 149 as the d-axis instruction voltage vd ^ж . The adder 147 adds the output of the ACR 143 and the output of the decoupling control unit 139 and outputs the addition output to the dq / uvw conversion unit 149 as the q-axis instruction voltage vq ^ж .

The dq / uvw conversion unit 149 performs uvw conversion on the d-axis command voltage vd ^ж and the q-axis command voltage vq ^ж to convert them into three-phase three-phase command voltages vua, vwa, vva of u phase v phase w phase. The three-phase instruction voltages vua, vwa, vva are supplied to the auxiliary inverter 3.

  FIG. 4 is a diagram illustrating a simulation result at the time of motor acceleration before applying the damping control at the time of single operation. FIG. 5 is a diagram illustrating a simulation result at the time of motor acceleration after applying the damping control at the time of single operation. FIG. 6 is a diagram showing simulation conditions.

  In the simulation after applying the damping control shown in FIG. 5, a constant torque load 35 Nm (1 p.u.) is added as a load after the acceleration time is over. The acceleration time was set to 0.164 s as the rated acceleration time.

  Before the damping control shown in FIG. 4 is applied, the load angle due to the turbulence oscillates immediately after the start of acceleration, causing vibrations in the torque and the rotational speed.

  On the other hand, after applying the damping control shown in FIG. 5, the vibration of the load angle is observed immediately after the start of acceleration, but it can be seen that the vibration is converged by the damping control. As a result, vibrations of torque and rotational speed are suppressed, and the rotational speed follows the speed command.

  In addition, the rated torque was applied after the acceleration time ended, and torque and speed fluctuations due to damping control were suppressed even when load fluctuations occurred. Thereby, it can be confirmed that the turbulence can be suppressed by the damping control.

  In order to confirm whether the auxiliary inverter operates only when turbulence occurs, the output torque T, the torque Tm contributing to the dq-axis current of the main inverter 1, and the torque (dumping torque) TD contributing to the dq-axis current of the auxiliary inverters 3a to 3c Pay attention.

  From FIG. 5, it is confirmed that the damping torque TD is generated so as to cancel the vibration when the torque T is vibrated by adding the damping torque TD to the torque Tm contributing to the dq axis current of the main inverter 1. it can.

  FIG. 7 is a diagram illustrating a simulation result during parallel operation to which damping control is applied. Caption suffixes are assigned 1 and 2 respectively to distinguish two permanent magnet synchronous motors. For example, rotational speeds ω1, ω2, torques T1, T2, and auxiliary output voltages P1, P2.

  The simulation conditions are the same as when the permanent magnet synchronous motor is operated alone. However, since the two permanent magnet synchronous motors are operated in parallel, the output power is standardized by the sum of the rated outputs of the two permanent magnet synchronous motors. The acceleration time was 0.164 s.

  When damping control is applied, turbulence occurs in torque and rotational speed after starting acceleration as in the case of isolated operation. But then it has converged.

  In addition, when the rated torque is input to each permanent magnet synchronous motor at different timings after reaching the rated rotational speed, load fluctuation occurs, but the operation is stable without problems.

  Furthermore, parallel operation can be performed even when the load balance is different. Since the auxiliary inverter is not operating after the vibration has converged, it can be confirmed that the auxiliary inverter is operating only when turbulence occurs, and the same effect as in the case of isolated operation can be obtained. Further, it is possible to confirm that stable operation is possible by suppressing turbulence even during acceleration of the permanent magnet synchronous motor.

  Focusing on the output power, since the parallel operation is performed, the output voltage of the main inverter 1 outputs twice the rated output power (1 p.u.), whereas the output power of the auxiliary inverter is , 0.25 p. u. Output.

  As compared with the result of the single operation, it can be seen that the capacity of the main inverter 1 increases as the number of permanent magnet synchronous motors in parallel increases, but the capacity of the auxiliary inverter does not change.

  Furthermore, since the output power and current of each auxiliary inverter change by adjusting the damping gain Kd in the same manner as in isolated operation, the capacity of each auxiliary inverter is less than 25% of the capacity of the main inverter 1. Can be configured.

  This is the same even when the number of parallel units increases, and it can be seen that each auxiliary inverter can be configured with a smaller capacity as compared with the main inverter 1 as the number of parallel units increases.

  It is confirmed by simulation that parallel operation is possible even when the number of parallel units is three or more. Since the turbulence is suppressed by performing damping control with each permanent magnet synchronous motor, there is no limit to the number of units in parallel.

  Thus, according to the control device for the permanent magnet synchronous motor of the first embodiment, the plurality of permanent magnet synchronous motors 5a to 5c can be driven by the main inverter 1, and the auxiliary windings 9a to 9c can be driven by the plurality of auxiliary inverters 3a to 3c. Current flowing through the permanent magnet synchronous motors 5a to 5c is passed through the permanent magnet synchronous motors 5a to 5c, so that the vibration torque can be offset. Vibration can be suppressed.

  The main inverter 1 operates a plurality of permanent magnet synchronous motors 5a to 5c in parallel by V / f control, and the auxiliary inverters 3a to 3c perform current control individually by vector control and operate as a speed controller as a damping controller. By doing so, damping control can be performed via the auxiliary windings 9a to 9c, and turbulence can be suppressed.

Specifically, the adder 131 obtains a deviation Δω between the angular velocity command ω ^ж and the rotational angular velocity ω of the permanent magnet synchronous motor, and the damping control unit 133 multiplies the deviation Δω obtained by the adder 131 by the damping gain Kd. Since the q-axis current command value iq ^ж is obtained, the output voltage and current of each of the auxiliary inverters 3a to 3c can be adjusted by adjusting the damping gain Kd. That is, damping control can be performed to suppress turbulence.

1 Main inverter 3, 3a-3c Auxiliary inverter
5,5a-5c Permanent magnet synchronous motor (PM)
7, 7a-7c Main winding
9, 9a to 9c Auxiliary winding 11 Main inverter controller 13 Auxiliary inverter controller 15 Pulse generator 17 Current detectors 19, 131, 135, 137, 145, 147 Adder 111 f / V converter 115 rδ / 3φ conversion Part 133 damping control part 134,149 dq / uvw conversion part

Claims (3)

A plurality of permanent magnet synchronous motors each having a main winding and an auxiliary winding;
A main inverter connected to the main winding of each of the plurality of permanent magnet synchronous motors;
Provided corresponding to the plurality of permanent magnet synchronous motors, connected to the auxiliary windings of the permanent magnet synchronous motors, and caused by turbulence due to fluctuations in the load angle of the permanent magnet synchronous motors via the auxiliary windings A plurality of auxiliary inverters for causing a current to generate torque to cancel torque vibration to flow through the permanent magnet synchronous motor;
A control device for a permanent magnet synchronous motor, comprising: A main inverter control unit for controlling the main inverter by voltage / frequency control and operating the plurality of permanent magnet synchronous motors in parallel;
Provided in correspondence with the plurality of auxiliary inverters, individually controlling the current flowing through the auxiliary inverter by vector control and damping control via the auxiliary winding to generate torque that cancels torque vibration caused by the turbulence A plurality of auxiliary inverter controllers that cause current to flow through the permanent magnet synchronous motor;
The control apparatus of the permanent-magnet synchronous motor of Claim 1 characterized by the above-mentioned. Each of the plurality of auxiliary inverter controllers is
A first dq / uvw converter that converts a three-phase current flowing through the auxiliary inverter into a d-axis current detection value and a q-axis current detection value;
An adder for obtaining a deviation between an angular velocity command and a rotational angular velocity of the permanent magnet synchronous motor;
A damping control unit that obtains a q-axis current command value by multiplying the deviation obtained by the adder by a damping gain;
The d-axis command voltage obtained based on the d-axis current command value and the detected d-axis current value and the q-axis command voltage obtained based on the q-axis current command value and the q-axis current detected value are converted into a three-phase command voltage. A second dq / uvw converter for converting and supplying to the auxiliary inverter;
The controller for a permanent magnet synchronous motor according to claim 2, comprising:

Images