JPS62239891A - Control unit of non-commutator dc motor - Google Patents

Abstract

PURPOSE:To prevent the failure of starting due to an incorrect timing of starting, by interrupting the starting while a magnet rotor is rotating. CONSTITUTION:In case amagnet rotor 5 is rotating though current feeding is stopped to an armature winding 4, the counter-electromotive voltage generates in the armature winding 4. On that account, the signal of relative position of the magnet rotor 5 is generated in the output of a counter-electromotive voltage detection circuit 6. An input change detection circuit 11 outputs an H-level signal when the output of the counter-electromotive voltage detection circuit 6 is generated. When the output of an input change detection circuit 11 is at H-level, a starting circuit 10 is controlled so as not to actuate the motor.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is directed to the back electromotive force induced in the armature winding. It is related to the device.

BACKGROUND OF THE INVENTION In recent years, commutatorless DC motors have been used in various fields because of their high efficiency and the fact that the number of rotations can be easily varied by simply changing the applied voltage. However, in order to operate a commutatorless motor by controlling the operation timing and time of the semiconductor switching elements, a position detection sensor such as a Hall element is generally required. However, when it is desired to use a commutatorless DC motor in a place such as an electric compressor that is used in a very harsh operating environment such as high temperature, high pressure, and oil, there is a problem with the reliability of the position detection sensor. Therefore, in recent years, various methods have been proposed in which the relative position of the magnet rotor is detected from the back electromotive force of the armature winding, and the semiconductor switching elements are controlled using the detected signal.

An example of the conventional control device for the above-described commutatorless DC motor will be described below with reference to the drawings.

FIG. 3 shows a conventional control device for a non-commutated DC motor. Reference numeral 1 designates a DC power supply, and 2 designates a semiconductor commutator device formed by connecting six semiconductor switching elements 81 to S6 in a three-phase bridge connection.

3 is a commutatorless DC motor having an armature winding 4 and a magnet rotor 5. 6 is the winding voltage Vp of armature winding 4, =
A back electromotive voltage detection circuit 7 which inputs Vc is a drive circuit which receives the output of the back electromotive voltage detection circuit 6 and drives the semiconductor switching elements 81 to S6 of the semiconductor commutator device 2. 8 is a resistor inserted between one end of the DC power supply 1 and one end of the input of the semiconductor commutator, and 9 is a current detection circuit that detects a current based on the voltage generated across the resistor 8. 10 is a starting circuit that operates the drive circuit 7 at the time of starting.

The operation of the control device for a commutatorless motor configured as described above will be described below.

First, when the motor is stopped, no back electromotive force is generated in the armature winding 4, so the relative position of the magnet rotor 6 cannot be detected by the back electromotive voltage detection circuit 6.
The drive circuit 7 is operated to control the semiconductor switching elements 81 to S6 of the semiconductor commutator device 2, and the armature winding 4
Excite. By sequentially switching this excitation, a rotating magnetic field is generated inside the armature. The magnet rotor 5 rotates in synchronization with this rotating magnetic field. The rotation speed of the magnet rotor 6 can be increased by sequentially increasing the frequency of the rotating magnetic field. As the rotation speed of the magnet rotor 6 increases and the motor rotates, a back electromotive force is generated in the armature winding, and the relative position of the magnet rotor 5 can be detected by the back electromotive voltage detection circuit e. A drive circuit 7 is controlled by an electromotive voltage detection circuit 6.

The back electromotive voltage detection circuit 6 detects the winding voltage Vp of the armature winding 4, -
Since the relative position of the nine-magnet rotor 6 is detected by taking only the component of the back electromotive force from the V C, stable operation can be obtained in the same way as when a position detection sensor such as a Hall element is used.

Further, when the voltage generated across the resistor 8 exceeds a certain value (that is, an overcurrent flows), the current detection circuit 9 issues a signal to stop the operation of the drive circuit and the magnet rotor 5.

Problems to be Solved by the Invention However, the above configuration has the following problems. A state in which the magnet rotor 6 is rotating (for example,
If the magnet rotor 6 is rotating due to inertia even though the power supply to the armature winding 4 has been stopped, or if it is being forcibly rotated from the outside, etc.) A signal is sent from the circuit 10 to the drive circuit 7 and the semiconductor switching elements 81 to S6 of the semiconductor commutator device 2
make it work. However, since the magnet rotor 6 is rotating, there is a mismatch between the back electromotive force generated in the armature winding 4 and the voltage applied to the semiconductor commutator device 2, resulting in a brake mode, and the magnet rotor 5 applies braking. However, there was a problem in that the starting timing was not correct and the engine could not be started.

In view of the above-mentioned problems, the present invention has been developed so that the magnet rotor has inertia.

To provide a control device for a commutatorless motor that can completely stop and then start the motor when it is rotating due to an external cause or the like.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has a non-commutator right rim.
a back electromotive voltage detection circuit that detects the relative position of the magnet rotor; a drive circuit that drives the semiconductor switch and notching element of the semiconductor commutator device by the output of the back electromotive voltage detection circuit; The starting circuit includes a starting circuit that rotates from a state, and an input change detecting circuit that receives an output signal of the back electromotive voltage detecting circuit and controls the starting circuit.

Effect: With the above configuration, the present invention generates a back electromotive force in the armature winding when the magnet rotor is rotating, and the output of the back electromotive voltage detection circuit is output as a signal indicating the relative position of the magnet rotor. Ru. While this signal is output, the input change detection circuit assumes that there is a change in the input and waits for the operation of the starting circuit, and assumes that there is no change in the input and starts the operation of the starting circuit, thereby preventing the magnet rotor from starting while it is rotating. By doing this, it is possible to start the engine reliably.

Embodiment Hereinafter, a control device for a commutatorless DC motor according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a control device for a commutatorless DC motor in one embodiment of the present invention. 1 to 1o in Figure 1
Since it is the same as the conventional example, the explanation will be omitted. Reference numeral 11 denotes an input change detection circuit which receives the output of the back electromotive voltage detection circuit 6 and controls the starting circuit 1Q.

The operation of the control device for a commutatorless DC motor configured as described above will be described below.

First, in FIG. 1, when the magnet rotor 5 is rotating even though the power supply to the armature winding 4 is stopped, a back electromotive voltage VA is generated in the armature winding 4.

V B and V c are generated. Since the back electromotive voltage is generated in this way, the output a of the back electromotive voltage detection circuit 6,
b.

A signal indicating the relative position of the magnet rotor 5 is generated at C.

In the input change detection circuit 11, the output a of the back electromotive voltage detection circuit 6
, b, and c are output, the output d is set to 'H' level, and when outputs a, b, and c are not output, the output d is set to 'H' level.
′! The i-"L" level is set. When the output of the input change detection circuit 11 is at the 'H' level, the starting circuit 1o is controlled not to operate, and when the output of the input change detection circuit 11 is at the 'L' level, the starting circuit 1o is controlled to not operate.
Control to permit operation of 0. Further, FIG. 2 shows an example of a specific circuit of the input change detection circuit 11. 12-1
4 is a monostable multivibrator with input a.

Input changes to b and c (e.g. 'H''-''L'', L''-wH
''), a pulse signal is generated. 15 is O
In the R circuit, if a pulse occurs in even one of the outputs of the monostable multi-by-breaks 12 to 14, the output becomes 1H'' level. 16 is a timer whose reset is connected to the output of the OR circuit 15. When the reset signal is at the ``H'' level, the timer operation starts and the @H'' level is output to the output d. When the timer operation ends, the "L" level is output to the output d. If there is an input change in the knob inputs a, b, c, the timer 16 is always reset and the output d continues to hold the @H'' level. - If there is no input change in the universal power a, b, c , the timer 16 ends its timer operation and outputs the L'' level.

As described above, according to this embodiment, the output of the back electromotive voltage detection circuit 6 is used as input to control the starting circuit 1o. By providing the input change detection circuit 11, the starting circuit 1o is guaranteed to be started while the magnet rotor 6 is rotating. This eliminates the possibility of starting failure due to incorrect starting timing, and prevents the semiconductor switching element 8 from being affected by the large winding current generated when braking is applied.
1 to S6 and demagnetization of the magnet rotor 6 can be prevented.

Effects of the Invention As described above, the present invention includes a back electromotive voltage detection circuit that detects the relative position of the magnet rotor based on the back electromotive force generated in the armature winding, and a back electromotive force detection circuit that detects the semiconductor switching using the output of the forward electromotive force detection circuit. By providing a drive circuit that drives the element, a starting circuit that causes the magnet rotor to rotate from a stopped state, and an input change detection circuit that receives an output signal of the back electromotive voltage detection circuit and controls the starting circuit. Since the magnet rotor will never start while it is rotating, it will definitely stop +1-1- and start will fail due to misalignment. This allows for reliable starting.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a control device for a non-commutated DC motor according to an embodiment of the present invention, Fig. 2 is a block diagram of an input change detection circuit of Fig. 1, and Fig. 3 is a block diagram of a conventional non-commutated DC motor. FIG. 2 is a block diagram of a control device. 1... DC power supply, 2... Semiconductor commutator device, 3... Commutatorless DC motor, 6.
... Back electromotive force detection circuit, 7... Drive circuit,
11-... Input change detection circuit. Name of agent: Patent attorney Toshio Nakao and one other person I-
Wataru Electric Row,

Claims (1)

[Claims] A semiconductor commutator device formed by connecting an armature winding with a neutral point ungrounded, six semiconductor switching elements connected in a three-phase bridge, a magnet rotor, and a back electromotive force generated in the armature winding. a back electromotive voltage detection circuit that detects the relative position of the magnet rotor, a drive circuit that drives a semiconductor switching element of the semiconductor commutator device by the output of the back electromotive voltage detection circuit, and a state in which the magnet rotor is stopped. 1. A control device for a non-commutated DC motor, comprising: a starting circuit that rotates the motor; and an input change detection circuit that receives an output signal of the back electromotive voltage detection circuit and controls the starting circuit.