JPS61214788A - Starter of commutatorless motor - Google Patents

Abstract

PURPOSE:To suppress the current value at starting time except the normal value and to reduce the loss, the cost and a space by controlling power supply to a stator winding by the logic product of a soft starting signal and the detection signal of a rotor position. CONSTITUTION:A soft start signal generator 6 is formed of an oscillator 7, a oneshot multivibrator 8. The generator 6 generates a soft start signal having constant OFF time for controlling the energizing time of predetermined switching elements 10-15 at starting time. A controller 5 controls the elements 10-15 by the position detection signal from a position detector 4 for detecting the position of a rotor 19, and outputs a control signal for controlling to sequentially switch the power supply to stator windings 16-18. A logic product circuit 9 takes a logic product of a signal from the multivibrator 8 and a control signal from the controller 5 to control the On and OFF of the elements 10-15.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a position detection type non-commutated motor which rotationally drives a rotor by sequentially switching and controlling the current flowing through a plurality of stator windings according to the position of the rotor. This invention relates to a starting device for a sub-motor.

BACKGROUND TECHNOLOGY In general, electric motors with a commutator have advantages such as a wide variable range of rotational speed, the ability to rotate at high speed and obtain high output even if the capacity is small, but due to the use of a commutator, The disadvantage is that it has a short lifespan. Therefore, recently there has been a trend to change the commutator mechanism to a purely electronic one and eliminate commutator. However, when this type of motor starts, the rotation speed is low and the voltage induced by the stator winding is low, so a large current flows for a long time in the stator winding and the switching element that controls its power supply. Become.

One way to counter this is to suppress the current by installing a starting resistor in the current path to the stator windings, but this method causes a large loss in the starting resistor, and it takes a relatively large amount of time to disconnect the starting resistor. Another method is to suppress the large current at startup by installing a switching element in the current path to the stator windings and turning the power supply on and off finely.

Problems to be Solved by the Invention In such conventional techniques, large capacity resistors and switching elements are required to be installed in series in the current-carrying path to the windings, which requires a large amount of space and is costly. It was something like that.

- The present invention has been made in view of the above points, and an object of the present invention is to provide a starting device for a commutatorless motor that is inexpensive, has low loss, and has a small space.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a soft start signal of a soft start signal generation circuit that keeps the off time of the switching element constant and increases the energization time as the switching element changes over time, and a rotation of the rotor. The configuration is such that a switching element that controls power supply to the stator windings is turned on and off by an AND circuit that outputs an AND with a position detection signal of a position detection device that detects a position.

Effect of the Invention With the above-described configuration, the AND circuit shortens the energization time of the switching element that controls the power supply to the stator windings at startup, keeps the OFF time constant, and performs fine on/off control, thereby reducing inrush current. The peak of is suppressed, and the switching element can be turned off reliably.

Embodiment FIG. 1 shows a starting device for a commutatorless motor according to the present invention.
It is a phase winding type. 1 is the main power supply, 2 is the circuit power supply, 3
is GND, 4 is a position detection device that detects the rotational position of the fixed magnetized rotor 19, and 6 is a position detection signal from the position detection device 4 to control the switching elements 10 to 16 to supply power to the stator windings. A control unit that outputs a control signal for sequential switching control; 7 is an oscillation circuit whose frequency of oscillation output is variable at the time of startup according to changes over time after startup; 8 is an oscillation circuit whose frequency of oscillation output is variable depending on the rise or fall of the oscillation circuit 7; The oscillation circuit 7 and the one-shot multivibrator circuit 8 form a soft start signal generation circuit 6, which is a multivibrator circuit that outputs low pulses. This circuit 6 generates a soft start signal with a constant off time that controls the predetermined energization time of the switching elements 1Q to 16 at startup. 9 performs the logical product of the signal from the one-shot multivibrator circuit 8 and the control signal, and selects switching elements 10 to 9;
This is an AND circuit that turns on and off 16 signals. The switching elements 10 to 15 are connected to the stator windings 16 to 18, respectively, and control the power supply thereto. The stator windings 16 to 18 provide rotational force to the rotor 19.

Figure 2 shows the operating waveforms of each part in Figure 1, where a is the output waveform of the oscillation circuit 7 whose oscillation period changes over time after startup, and b is the input waveform of the one-shot multivibrator circuit 8. This is the output when the slow start signal is reached. In this example, the switching element is turned off when the output is low, but the off time is set so that the switching element is completely turned off. C is control signal 1
where d is the logical product of the slow start signal and the control signal C, so that the switching element is turned on when this signal is NO. When controlled in this way, the current applied to the switching element and stator winding is e
Therefore, it is possible to keep it below the steady-state value.

In addition, in this example, the soft start signal was realized using an oscillation circuit and a one-shot multivibrator circuit.
Other circuits may be used, but it is clear that the same effect can be achieved as long as the soft start signal has a constant off time and an on time that increases with time. n (n is an integer greater than or equal to 2)
It is clear that a phase winding type may also be used.

Effects of the Invention As described above, according to the configuration of the present invention, it is possible to suppress the current value at the time of starting a commutatorless motor to a steady value or less, and at this time, the off time of the switching element can be adjusted appropriately. By setting it to , very reliable and stable operation can be obtained. Furthermore, since the signal processing is at the level of an electronic circuit, it has low loss and can be realized at low cost and in a small space, which has great effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a starting device for a commutatorless motor according to an embodiment of the present invention, and FIG. 2 is a time chart for explaining the operation at the time of starting shown in FIG. 1, respectively. 4...Position detection device, 6...Control unit,
6... Soft start signal generation circuit, 7...
...Oscillation circuit, 8...One-shot multivibrator circuit, 9: ...AND circuit, 10-1
6... Switching element, 16-18... Stator winding, 19... Rotor.

Claims (2)

[Claims] (1) a fixed magnetized rotor, a stator winding applied to two or more n phases that provide rotational force to the rotor, a position detection device that detects the rotational position of the rotor; a switching element connected to each of the stator windings to control power supply to the winding; and a switching element connected to each of the stator windings to control power supply to the stator winding, and a position detection signal from the position detection device to control the switching element to control power supply to the n-phase stator winding. comprising a control unit that outputs a control signal for sequential switching control, and a soft start signal generation circuit that generates a soft start signal that keeps the off time of the switching element constant and increases the energization time as the switching element changes over time;
A starting device for a non-commutated motor that starts the rotor by controlling the switching element using an AND circuit that outputs an AND of the control signal and the soft start signal. (2) The soft start signal generation circuit consists of an oscillation circuit whose oscillation output frequency is variable as it changes over time after startup, and a one-shot multivibrator circuit which outputs a pulse of a constant width from the rise or fall of the oscillation output. A starting device for a non-commutator motor according to claim 1, wherein the output signal of the one-shot multivibrator circuit is used as a soft start signal at the time of starting.