JPH0683589B2 - Controller for non-commutator motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for a non-commutator motor that uses a permanent magnet for a rotor.

<Prior Art> As shown in FIG. 4, in a conventional non-commutator motor M1 using a permanent magnet rotor, a DC voltage obtained by smoothing an AC power supply 1 by a converter 2 is switched by an inverter circuit 3 and a motor winding is performed. An AC voltage was applied to the line to operate it. Then, the permanent magnet rotor 4 is detected by the position detection sensor 6, the signal is input to the control circuit 7, the chopping duty is changed so as to approach the target rotation speed, and a switching signal is sent to the inverter circuit 3. Was there.

Normally, a hall element is used as the position detection sensor 6, but there are drawbacks such as variations in characteristics of the hall element and a large number of lead lines.

Therefore, it is possible to rotate the non-commutator motor by performing self-commutation by detecting the position of the permanent magnet rotor by using the counter electromotive force induced in the motor winding without using the position detection sensor 6. . However, in the sensorless method using the counter electromotive force, the counter electromotive force is not generated while the non-commutator motor is stopped, and therefore the synchronous commutation method must be used for starting.

In this synchronous commutation method, the non-commutator motor is rotated as a synchronous motor with a low-frequency drive pattern at startup, and this drive signal pattern is gradually raised to a high frequency, causing a back electromotive force of the motor winding. Also grows. Then, when the position detection signal sufficiently follows, the commutation is switched to.
Also, during this synchronous commutation, the chopping duty is also gradually increased in proportion to the time, but unless the curve is matched with the load, the torque shortage against the load is removed when switching to self-commutation. In some cases, the input signal of the position detection sensor and the drive output signal from the control circuit 7 may oscillate due to excessive torque, resulting in step-out. This is because the effective value of the voltage applied to the motor winding is proportional to the duty of the chopping pulse and the peak value of the pulse. The synchronous commutation is generally from several% to around 20% of the chopping duty, and the peak value of the pulse has a large effect in the range where the chopping duty is small.

Here, the peak value of the pulse means the AC power supply 1 and the converter 2
DC voltage smoothed by. That is, as shown in the diagram of FIG. 5 in which the time T from the start is on the horizontal axis and the effective voltage value V applied to the motor winding is on the vertical axis, the time of synchronous commutation and the chopping duty are shown. The tee relationship is balanced like the curve of the solid line D2, but if the DC voltage is high, it is like the curve of the broken line D1, and if it is low, it is the region where the step out is likely to occur (the shaded part). Approach.

<Purpose> In view of the above points, the present invention changes the curve with respect to the time of the chopping duty according to the value of the DC voltage obtained by smoothing the AC power supply by the converter at the time of synchronous commutation, and changes from the synchronous commutation to the self-commutation. An object of the present invention is to provide a control device capable of eliminating a step-out that tends to occur when switching to a flow and enabling stable operation of a non-commutator motor.

<Example> Hereinafter, an example of the present invention will be described with reference to FIG.
According to the present invention, the DC voltage obtained by smoothing the AC power supply 8 by the converter 9 is switched by the inverter circuit 10 in which six transistors are connected in three-phase bridge, and the neutral point non-grounded Y-connected motor winding is connected. In a control device having a control circuit 14 for applying an AC voltage, varying the duty and checking the rotor speed of the rotor of the non-rectifier motor, the non-rectifier motor is controlled based on the voltage across the terminals of the motor winding. Is provided with a position detection circuit 13 for detecting the position of the permanent magnet rotor 11, and the function of performing self-commutation of the non-commutator motor based on the output signal detected by the position, and the synchronous commutation curves A, B, C at start-up. The AC power supply 8 from among (the duty variable curve of the chopping with respect to the time of synchronous commutation)
The control circuit 14 is provided with a function of selecting a suitable curve according to the value of the DC voltage smoothed by the converter 9 and changing the checking duty according to this curve.

Next, the operation will be described. A DC voltage obtained by smoothing the AC power source 8 by the converter 9 is switched by the inverter circuit 10, and the AC voltage is applied to the motor winding to operate the electric motor M2. At this time, the position of the permanent magnet rotor 11 is detected by inputting the terminal voltage of the motor winding to the position detecting circuit 13 to detect the position and inputting it to the control circuit 14. And control circuit
At 14, the chopping duty is varied so as to approach the target rotation speed, and a switching signal is sent to the inverter circuit 10. Here, in the synchronous commutation at the time of startup, as shown in the diagram of FIG. 2B, the time T from the startup is on the horizontal axis and the effective voltage value V applied to the motor winding is on the vertical axis. Prepare a plurality of curve A, B, C of the tuning duty, and select the curve A or B or C suitable for it according to the value of the DC voltage like the flow chart of the control circuit 14 in FIG. , Wait for the lapse of time T1 and switch to self-commutation. And prevent step-out at that time. That is, when the DC voltage is high, the chopping duty is suppressed to be small, and when the DC voltage is low, the chopping duty is increased, which is clear from the comparison between FIGS. 2 (a) and 2 (b). As described above, the area (shaded area) where out-of-step is likely to occur is greatly reduced.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

<Effect> As is apparent from the above description, according to the present invention, a DC voltage obtained by smoothing an AC power supply by a converter is switched by an inverter circuit, and an AC voltage is applied to a motor winding.
The voltage is duty-variable and is checked, and in a control device that has a control circuit that controls the rotor rotation speed of the non-rectifier motor, a position detection circuit that detects the position of the rotor of the non-rectifier motor is provided and the position is detected. The function of performing self-commutation of the non-commutator motor based on the output signal and the curve of the chopping duty against the time of synchronous commutation by the value of the DC voltage obtained by smoothing the AC power supply by the converter at the time of startup. The present invention relates to a control device for a non-commutator motor, wherein the control circuit is provided with a function of changing the selecting duty according to the curve and changing the checking duty.

Therefore, according to the present invention, in a commutatorless motor using a rotor, when switching from synchronous commutation to self-commutation at start-up, the fluctuation of the power supply voltage or the smoothed DC voltage is also eliminated. There is an excellent effect that stable operation can be performed without adjusting.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a controller for a non-rectifier motor according to the present invention, and FIGS. 2 (a) and 2 (b) are applied to the motor windings with the time T from the start as the horizontal axis. FIG. 3 is a flow chart of the control circuit, FIG. 4 is a block diagram of the control device of the conventional example, and FIG. 5 is the time T from the start in the horizontal axis. FIG. 5 is a diagram in which the effective voltage value V applied to the motor windings is plotted on the vertical axis. A, B, C: Synchronous commutation curve, 8: AC power supply, 9: Converter, 1
0: Inverter circuit, 11: Rotor, 13: Position detection circuit, 14:
Control circuit.

Claims (1)

[Claims] 1. A rotor for a non-commutator motor, wherein a DC voltage obtained by smoothing an AC power source by a converter is switched by an inverter circuit, an AC voltage is applied to a motor winding, and the duty is variable so that the voltage is checked. In a control device having a control circuit for controlling the rotation speed, a position detection circuit for detecting the position of the rotor of the non-commutator motor is provided, and a function of performing self-commutation of the non-commutator motor based on the output signal detected by the position detection circuit. And, at the time of start-up, the curve of the duty of duty for the time of synchronous commutation is selected by the value of the DC voltage smoothed by the converter at the time of start-up, and the duty of duty is checked according to this curve. A control device for a non-commutator motor, characterized in that the control circuit is provided with a changing function.