JPH0832190B2 - Synchronous motor controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor control device that controls a motor torque by the amplitude and phase angle of a voltage applied to a synchronous motor.

<< Summary of the Invention >> According to the present invention, the dependency of the drive voltage applied to the motor on the rotation speed of the motor is released during low-speed rotation of the synchronous motor.

<< Prior Art >> In this type of device disclosed in Japanese Patent Application No. 61-228478, a target amplitude of a voltage applied to a motor is obtained based on the number of revolutions of a synchronous motor and a torque command thereto.

Then, the load angle of the synchronous motor is obtained based on the motor rotation speed and the torque command, and the target phase angle of the motor applied voltage is obtained by adding the load angle to the rotation phase angle of the synchronous motor.

Further, a sine voltage command determined by the target amplitude and phase angle thus obtained is generated, and the drive voltage applied to the synchronous motor is controlled according to this command.

As a result, a drive voltage of, for example, a PWM wave is applied to the synchronous motor, and torque corresponding to the torque command is output from the motor shaft.

<< Problems to be Solved by the Invention >> Here, the output torque of the synchronous motor is different depending on the rotational phase angle (stop position of the rotor) of the rotor and the stator despite the control of the drive voltage applied to the synchronous motor. Changes according to the positional relationship of.

Therefore, conventionally, there has been a problem that the motor torque largely changes due to the positional relationship between the rotor and the stator during low-speed rotation of the synchronous motor, and as a result, torque pulsation causes vibration.

This is particularly remarkable in the case of a permanent magnet type motor in which the cogging torque pulsation at the time of starting is large.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a synchronous motor control device capable of completely preventing torque pulsation during low speed rotation of the synchronous motor.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention provides: a motor rotation speed detection means for detecting the rotation speed of a synchronous motor; and a target of a motor applied voltage based on the detected rotation speed and a torque command. The voltage amplitude calculation means for obtaining the amplitude, the load angle calculation means for obtaining the target load angle of the synchronous motor based on the detected rotation speed and the torque command, and the target phase angle of the motor applied voltage are calculated by adding the target load angle and the detected phase angle. A voltage phase angle calculating means to be obtained, a voltage command generating means for generating a sine voltage command of a target phase angle with a target amplitude, a voltage control means for controlling the drive voltage applied to the synchronous motor according to the sine voltage command, and preset The motor rotation speed comparison means for comparing the low speed rotation speed with the detected rotation speed, and the detection of the target amplitude by the voltage fluctuation calculation means when the detected rotation speed does not reach the set rotation speed. Having an amplitude calculating characteristic control means for breaking the dependency on the rolling speed, and wherein the.

<< Operation >> In the present invention, when the motor rotation speed does not reach the set low speed rotation speed, the target amplitude of the motor applied voltage is obtained only based on the torque command regardless of the motor rotation speed.

<< Embodiment >> A preferred embodiment of an apparatus according to the present invention will be described below with reference to the drawings.

In FIG. 1, the rotational speed ω of the permanent magnet type synchronous motor 10
Is detected by the rotation speed sensor 12, and the detection signal is supplied to the voltage amplitude calculation circuit 14 and the load angle calculation circuit 16.

And accelerator opening sensor 17 (potentiometer, etc.)
The torque command T ^* indicated by the output voltage of is also given to the voltage amplitude calculation circuit 14 and the load angle calculation circuit 16.

Among them, the voltage amplitude calculation circuit 14 obtains the target amplitude V ^* of the motor applied voltage based on the detected rotation speed ω and the torque command T ^* , or only based on the torque command T ^* .

Further, the load angle calculation circuit 16 obtains the target load angle Δ ^* of the synchronous motor 10 based on both the detected rotation speed ω and the torque command T ^* .

The rotational phase angle θ of the synchronous motor 10 is detected by the phase angle sensor 18, and the detection signal is supplied to the adder 20.

This adder 20 receives the target load angle δ from the load angle calculation circuit 16.
^{* Is} also given, and in adder 20, phase angle θ and load angle δ ^*
The target phase angle ^* of the motor applied voltage is obtained by adding and.

The phase angle ^* obtained by the adder 20 and the amplitude V ^* obtained by the voltage amplitude calculation circuit 14 are given to the multiplier 22 as a command of the phase and amplitude of the motor applied voltage,
In the multiplier 22, three-phase sine of V ^* = V ^* sin (θ ^* + 2 / 3π) V ^* = V ^* sin (θ ^* + 4 / 3π) V ^* = V ^* sin (θ ^* + 6 / 3π) A voltage signal that is a wave signal is obtained.

The voltage command thus obtained by the multiplier 22 is supplied to the PWM oscillator 26 of the voltage control circuit 24.
In, the three-phase PWM signal corresponding to each voltage command is obtained.

The PWM signals are also supplied to the inverter 28 also provided in the voltage control circuit 24, and the current control elements inserted in the main circuits of the respective phases of the inverter 28 are switching-controlled by the PWM signals.

As a result, the drive voltage corresponding to the voltage command is applied from the inverter 28 of the voltage control circuit 24 to the permanent magnet synchronous motor 10, and the torque corresponding to the torque command T ^* is output from the motor shaft.

In the voltage amplitude calculation circuit 14 and the load angle calculation circuit 16, the voltage amplitude V ^* , as a function of the torque command T ^* and the motor speed ω,
The load angle δ ^* is stored on each Momelli map, and they are obtained by a variable search and an interpolation calculation.

Here, a switch 30 is provided on the input side of the detected rotation speed ω of the voltage amplitude calculation circuit 14, and a detection signal of the detected rotation speed ω is supplied to the voltage amplitude calculation circuit 14 via its a contact. .

The other contact b of the switching device 30 is grounded, and the switching contact is switched and controlled by the comparison signal of the comparator 32.

One of the comparison inputs of the comparator 32 is supplied with a low-speed set rotation speed from the rotation speed setting device 34, and the other comparison input is supplied with the rotation speed ω detected by the rotation speed sensor 12.

The switching contact of the switching device 30 is switched to the b contact by the comparison signal of the comparator 32 until the detected rotation speed ω reaches the set rotation speed, and when the detected rotation speed ω reaches the set rotation speed, the switching contact is changed. Is switched to the contact a.

This embodiment has the above configuration, and its operation will be described below.

After the permanent magnet type synchronous motor 10 is started, until the rotational speed (ω) reaches the rotational speed set by the setting device 34, the switching contact of the switching device 30 is switched via the contact b by the comparison signal of the comparator 32. It is grounded, and the detected rotation speed (ω) of the permanent magnet type synchronous motor 10 is not given to the voltage amplitude calculation circuit 14.

Therefore, only the torque command T ^{* from the} accelerator opening sensor 18 is given to the voltage amplitude calculation circuit 14, and the target amplitude V ^* is obtained based only on the torque command T ^* .

On the other hand, in the load angle calculation circuit 16, the detected rotation speed ω of the permanent magnet type synchronous motor 10 is given together with this torque command T ^* , and the target load angle δ ^{* of the} permanent magnet type synchronous motor 10 is obtained based on both of them.

Therefore, the multiplier 22 has a target load angle δ ^* and a detected phase angle δ
With voltage target phase angle theta ^* obtained by the addition of the target amplitude V ^* is given only by the torque command T ^*.

Therefore, the amplitude of the drive voltage applied to the permanent magnet type synchronous motor 10 is controlled not depending on the motor rotation speed (ω) but only on the torque command T ^*, and as a result, the motor torque at the low speed rotation is controlled. Pulsation is prevented.

After that, when the motor rotation speed (ω) reaches the setting rotation speed of the setting device 34, the switching contact of the switching device 30 is switched to the contact a by the comparison signal of the comparator 32, and therefore the voltage amplitude calculating circuit.
At 14, the target amplitude V ^* is obtained based on the torque command T ^* and the detected rotation speed ω.

Therefore, thereafter, the amplitude of the drive voltage applied to the permanent magnet type synchronous motor 10 is controlled with dependence on the motor speed (ω) as well as the torque command T ^* .

As described above, according to the present embodiment, the dependence of the amplitude of the motor applied voltage on the motor rotation speed is controlled to be released during the motor start and during its low speed rotation, so that the permanent magnet with a large cogging torque pulsation at the start is large. Type synchronous motor
Even if it is 10, it does not cause the pulsation of the motor torque,
Therefore, the vibration due to the pulsation can be surely prevented.

This is extremely suitable for a vehicle that uses the synchronous motor 10 as a driving source, and it is possible to significantly improve drivability and the like.

<Effect> As described above, according to the present invention, the control dependency of the motor applied voltage amplitude on the motor rotation speed is cut off during low-speed rotation of the motor. It can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an apparatus to which the present invention is applied. 10 ... Permanent magnet type synchronous motor 12 ... Rotation speed sensor 14 ... Voltage amplitude calculation circuit 16 ... Load angle calculation circuit 17 ... Accelerator opening sensor 18 ... Phase angle sensor 20 ... Adder 22 ... Multiplier 24 ... Voltage control circuit 26 ... PWM oscillator 28 ... Inverter 30 ... Switching device 32 ... Comparator 34 ... Rotation speed setting device

Claims (1)

[Claims] 1. A motor rotation speed detection means for detecting a rotation speed of a synchronous motor, a voltage amplitude calculation means for obtaining a target amplitude of a motor applied voltage based on the detected rotation speed and a torque command, and a detection rotation speed and a torque command. A load angle calculation means for obtaining the target load angle of the synchronous motor based on the voltage phase angle calculation means for obtaining the target phase angle of the motor applied voltage by adding the target load angle and the detected phase angle; and a sine of the target phase angle with the target amplitude. Voltage command generation means for generating a voltage command, voltage control means for controlling the drive voltage applied to the synchronous motor in accordance with a sine voltage command, and motor speed comparison for comparing a preset low speed rotation speed with a detected rotation speed And an amplitude calculation characteristic control means for cutting off the dependency of the target amplitude by the voltage swing calculation means on the detected rotation speed when the detected rotation speed does not reach the set rotation speed. To, synchronous motor control device, characterized in that.