JPS61295893A - Drive device of commutatorless motor - Google Patents

Abstract

PURPOSE:To set the current capacity of a switching element and the holding force of a permanent magnet to the capacity at rated value operation time by altering the limit value of a current supplied to a stator winding and the element in response to the rotating speed of a rotor. CONSTITUTION:Currents which flow to stator windings 4a-4c and switching elements 5a-5f are detected by a current detector 7, and the output is compared by a comparator 10 with the output of a referance voltage generator 9 for generating a stepwise reference voltage in response to the output of a rotation detector 8. A one shot multivibrator 11 generates a pulse signal of the prescribed width from the rise of the output of the comparator 10. A controller 13 inputs the outputs of a position detector 12 and the multivibrator 11, varies the limit value of the current supplied to the windings 4a-4c and the elements 5a-5f in response to rotating speed of a rotor 3, and the elements 5a-5f are turned OFF for the prescribed time when arrived at the limit value.

Description

[Detailed Description of the Invention] [Object of the Invention] The present invention rotationally drives a rotor by sequentially switching and controlling the current flowing through a plurality of stator windings according to the rotational position of the rotor, which is made of a permanent magnet. This relates to a drive device for a position detection type non-commutated motor, and its purpose 6 is to provide a drive device that can make the non-commutated motor compact and inexpensive. Electric motors with a commutator have the advantage of being able to vary the rotational speed, and even though their capacity is small, they can produce relatively high output at high speeds. This is a drawback. Therefore, recently, the commutator mechanism has been replaced with an electronic one and a non-commutator type. However, in these conventional motors, the induced voltage in the stator winding is low at startup and at low rotation speeds after startup, so a large current flows for a long time in the stator winding and the switching element that controls its current. become.

Therefore, the switching element needs to have a large capacity, and the permanent magnets forming the rotor need to have a large coercive force to prevent demagnetization.

An object of the present invention is to solve this problem and thereby make a commutatorless motor smaller and cheaper.

[Configuration of the Invention] The drive device for a commutatorless motor of the present invention includes:
A rotor such as a permanent magnet, an n-phase stator winding (n is an integer of 2 or more) that provides rotational force to the rotor, a position detector that detects the rotational position of the rotor, and the fixed A non-commutator motor comprising a plurality of switching elements each connected to a child winding and controlling the energization thereof, and a controller inputting the output of the position detector to control on/off of the plurality of switching elements. A current detector detects the current flowing through the stator winding and the switching element, and a current detector detects the rotation speed of the rotor and outputs a signal when the rotation speed reaches a predetermined rotation speed or more. a rotation detector; a reference voltage generator that generates a reference voltage whose level changes in m stages (m is an integer of 2 or more) according to the output of the rotation detector; the output of the current detector and the reference voltage; It has a comparator that compares the output of the generator with the output of the rotor, and a one-shot multivibrator circuit that generates a pulse signal of a constant width from the rise of the output of the comparator and outputs it to the controller. The limiting value of the current flowing through the stator winding and the switching element is changed according to the rotational speed of the stator winding, and when the limiting value is reached, the switching element is turned off for a certain period of time. Features.

Embodiments of the present invention will be described with reference to the drawings. Figure 1 is a diagram showing a drive system for a three-phase winding type non-commutator motor, in which 1 is the main power supply, 2 is the circuit power supply, 3 is the rotor made of a permanent magnet, and 4a
, 4b and 4c are stator windings, 5a to 5f are switching elements, and 5a to 6f are protection diodes connected in parallel with these. 7 is stator winding 4a, 4b, 4c
and a current detector that detects the current flowing through the switching elements 58 to 5f and outputs it as a voltage signal; 8 is the rotor 3;
A rotation detector that detects 0 rotation speed and outputs a signal when the rotation speed reaches a predetermined rotation speed or higher; 9 is a reference that generates a reference voltage whose level changes according to the output of the rotation detector 8; a voltage generator; 10 a comparator for comparing the output of the current detector 7 and the output of the reference voltage generator 9; 11 a comparator 1;
12 is a position detector that detects the rotational position of rotor 3; 13 is the output of one-shot multivibrator circuit 11 and position detector 12; This is a controller that inputs the output of the switching elements 5a to 5f to control on/off of the switching elements 5a to 5f.

Figure 2 is a time chart showing the operation of the device in Figure 1.
A is the rotational speed of the rotor 3 after startup, and the dotted line represents its signal. B is a reference voltage generator 9 corresponding to the rotation speed
, which corresponds to the current limit value, and C is actually the output signal of the switching elements 5a to 5f and the stator winding 4a1.
This is the waveform of the current flowing through 4b and 4C. D is an output signal of the comparator 10 which compares the outputs of the current detector 7 and the reference voltage generator 9, and becomes H when the output of the current detector 7 exceeds the output of the reference voltage generator 9. E is an output signal of the one-shot multivibrator circuit 11 which outputs a pulse of a constant width from the rising edge of the signal D, and when this signal is H, all switching elements 5a to 5f are turned off.

F represents on/off of one of the switching elements, and is turned on when it is H. The dotted line represents the ON pattern from the position detector 12. Note that while the one-shot multivibrator circuit 11 is outputting, it is sufficient to set a time during which the switching elements 5a to 5f are sufficiently turned off.

In the above embodiments, the drive device of the present invention was explained for a three-phase wire-wound type non-commutator motor, but this is an n-phase (n is 2
Needless to say, the present invention can be applied to electric motors with integers greater than or equal to the above. Furthermore, although the case where the reference voltage is switched in two stages has been described, this can be changed to m stages (yrx is an integer of 2 or more).

[Effects of the Invention] As described above, the drive device of the present invention sets the limit value of the current flowing through the stator winding and the switching element that controls its energization to a small value when the rotor is stopped or the rotation speed is low. The setting is set higher as the rotational speed increases, and when the limit value is reached, the switching element is turned off for a set period of time, so switching during startup and low speed rotation of commutatorless motors is possible. The current values of the elements and stator windings can be limited, and the current capacity of the switching elements and the coercive force of the permanent magnets constituting the rotor can be set to the capacities during rated operation. Furthermore, since the switching elements are controlled by signals from the controller 13, the device can be made smaller and simpler. Therefore, since the above-mentioned drawbacks of the conventional non-commutator motor are eliminated, the object of the invention can be achieved.

[Brief explanation of drawings]

Figure 1: Block diagram showing the configuration of the drive device for a commutatorless motor of the present invention Figure 2: Waveform diagram of signals in each part of the device shown in Figure 1

Claims (1)

[Claims] A rotor made of a permanent magnet, an n-phase (n is an integer of 2 or more) stator winding that applies rotational force to the rotor, a position detector that detects the rotational position of the rotor, and the stator. In a commutatorless motor comprising a plurality of switching elements each connected to a winding and controlling energization thereof, and a controller inputting the output of the position detector to control on/off of the plurality of switching elements. , a current detector that detects the current flowing through the stator winding and the switching element; and a rotation device that detects the rotation speed of the rotor and outputs a signal when the rotation speed reaches a predetermined rotation speed or higher. a detector, a reference voltage generator that generates a reference voltage whose level changes in m stages (m is an integer of 2 or more) according to the output of the rotation detector, and the output of the current detector and the reference voltage generator. a one-shot multivibrator circuit that generates a pulse signal of a constant width from the rise of the output of the comparator and outputs it to the controller; It is characterized in that it is configured to change a limit value of the current flowing through the stator winding and the switching element according to the rotational speed, and to turn off the switching element for a certain period of time when the limit value is reached. Commutatorless motor drive device with