JPS62185585A - Controller for commutatorless dc motor - Google Patents

Abstract

PURPOSE:To efficiently start a commutatorless DC motor by restarting the motor by timer means in a short time when the starting is failed and performing a protecting operation when the starting are failed continuously for a predetermined times. CONSTITUTION:The output of a counterelectromotive force detector 6 is input to a drive circuit 7 to drive semiconductor switching elements S1-S6 of a semiconductor commutator 2. This drive circuit 7 has operating means 7a, second timer means 7b, frequency detecting means 7c, modulo-N counting means 7d and first timer means 7e. When the commutator 2 fails to start, it is restarted in a short time, and when the failures of the starting continue for N times, it is handled similarly to a protecting operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a commutatorless DC motor that rotates a magnet rotor using a back electromotive force induced in an armature winding.

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 revolutions 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. There 3 ′\−
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 by the 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. 1 is a DC power supply, and 2 is a semiconductor commutator loaded with six semiconductor switching elements S1 to S6 connected in a three-phase bridge.

3 is a commutatorless DC motor having an armature winding 4 and a magnet rotor 6. 6 is the winding voltage of armature winding 4■8～■
A back electromotive voltage detection circuit inputs c, and a drive circuit inputs the output of the back electromotive voltage detection circuit 6 and drives the semiconductor switching elements 81 to S6 of the semiconductor commutator device 20. 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 protection detection circuit that detects a current based on the voltage generated across the resistor 8. The drive circuit 7 includes an operating means 7a for starting, running, and stopping the non-commutated DC motor 3, a second timer means 7b for generating a predetermined time T2, and a back electromotive voltage detection circuit 6. Frequency detection means 7 that detects the frequency of the output of and generates a signal when the detected frequency becomes higher than a certain frequency.
It is equipped with c.

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

Since no back electromotive voltage is generated in the armature winding 4 when the motor is stopped without switching, the relative position of the magnet rotor 6 cannot be detected by the back electromotive voltage detection circuit 6. Semiconductor switching element 81
~S6 is controlled to excite the armature winding 4. By sequentially switching this excitation, a rotating magnetic field is generated inside the stain. The magnet rotor 5 rotates in synchronization with this rotating magnetic field.

The number of rotations of the magnet rotor 5 can be increased by sequentially increasing the frequency of the rotating magnetic field. When the rotation speed of the magnet rotor 5 decreases to -L, a back electromotive force is generated in the armature winding as the motor rotates, and the relative position of the magnet rotor 5 can be detected by the back electromotive force detection circuit 6. When this happens, the output of the back electromotive voltage detection circuit 6 causes the operation means 7a to continue the rotation of the mortar. The back electromotive voltage detection circuit 6 detects the relative position of the magnet rotor 6 by taking only the component of the back electromotive force from the winding voltages vA to ■c of the armature winding 4, so a position detection sensor such as a Hall element is used. Stable operation can be obtained in the same way as when using this method. To stop the motor when the motor is short, the operating means 7a turns off all the semiconductor switching elements 81 to S6 of the semiconductor commutator device 20 to stop the motor. When the voltage generated across the resistor 8 exceeds a certain value (in other words, an overcurrent flows), a signal is output from the protection detection circuit 9.
The motor is stopped by the operating means 7a. However, when position detection is performed using a back electromotive force in this manner, starting may fail and the motor may lock. When locked, a back electromotive voltage Ov is generated in the armature winding 4, so the operation is performed in a closed loop between the back electromotive voltage detection circuit 6, drive circuit 7, and semiconductor commutator device 2, and the L component of the armature winding 4 causes The positive feedback has a high frequency inside the 9 closed loop (approximately 500 H in a 10 OW class commutatorless motor).
z or higher). This oscillation is detected by the frequency detection means 7C and a signal is sent to the operation means 7a to stop the operation of the motor. If the protection detection circuit 9 or the frequency detection means 7c still stops operating, the second timer means restarts the motor after a certain period of time T2 has elapsed. The above operation is shown in a flowchart as shown in FIG. In steps 10 and 11, the operating means performs the starting operation and the driving operation. At step 12, the presence or absence of oscillation operation is confirmed by the frequency detection means 7c. If there is no oscillation, the driving operation 11 is continued; if there is oscillation, the operating means 7a performs the stopping operation 13 to stop the motor. Even when the protection detection circuit 9 is activated, the protection operation 14 is performed and the stop operation 13 is performed. When the stop operation 13 is completed, the second timer 15 operates and waits for a time T2. After that, the starting operation was repeated from 10 again.

Problems to be Solved by the Invention However, the above configuration has the following problems. If the motor locks due to a failure in starting, or if oscillation is detected, the motor will stop and restart after time T2, just like the protective action.
Even if the engine fails to start, it will take a long time to restart because it will not restart unless the operator waits for a long time.

SUMMARY OF THE INVENTION In view of the problems mentioned above, the present invention provides a control device for a commutatorless DC motor that restarts the motor in a short time if the motor fails to start.

Means for Solving the Problems In order to solve the above problems, the control device for a non-commutator DC motor of the present invention detects the frequency of the output of a back electromotive voltage detection circuit, and detects a frequency higher than a certain frequency. frequency detecting means for stopping the operation of the non-commutated DC motor by means of an operating means when the frequency detecting means operates; N-ary counting means for counting the number of times the frequency detecting means operates; The second timer means generates a signal a predetermined time after the output signal of the N-ary counting means or the output signal of the protection detection circuit is generated.

Operation The present invention has the above-described configuration, so that the predetermined time T1 of the first timer means and the predetermined time T2 of the second timer means are set to T1(
T2, and if the engine fails to start, it will be restarted in a short time, and if the engine fails to start N times in a row, it will be handled in the same way as a protective operation.

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. In FIG. 1, 1 to 9 and 7a to 7C are the same as in the conventional example, so their explanation will be omitted. 7d
Numeral 7e denotes N-ary counting means for counting the number of times the frequency detecting means 7c operates, and first timer means 7e operates for a predetermined period of time when the frequency detecting means 7C operates.

The operation of the control device for a non-commutator DC motor constructed as described above will be explained with reference to FIGS. 1 and 2.

9'-- FIG. 2 shows a flowchart of the operation in FIG. 1. At 10.11, the operating means performs the starting and running operations. At step 12, the presence or absence of oscillation operation is confirmed by the frequency detection means 7C. If there is no oscillation, the driving operation 11 is continued, and if there is oscillation, the operating means 7a performs the stop operation 16 to stop the motor. The count value of the N-ary counter 7d is updated (up17), and it is determined in step 18 whether n=N. In the case of n4N, the first timer 19
operates and waits for time T1. After that, repeat the starting operation from 1o again. When n = H, the protection operation is performed as in the conventional example.

As described above, in this embodiment, the frequency detection means 7c detects the output frequency of the back electromotive voltage detection circuit 6 and causes the operation means 7a to perform the stop operation 16 when the detected frequency becomes higher than a certain frequency, and the frequency detection means 7c causes the operation means 7a to perform the stop operation 16. N-ary counting means 7d for counting the number of operations of means 7C, and frequency detection means 7
A first circuit that generates a signal after a predetermined time T1 after C operates.
The output signals of the timer means 7e and the N-ary counting means 7d or 10'' are output for a predetermined time T after the output signal of the protection detection circuit 9 is generated.
By providing the second timer means 7b which generates a signal after 2 seconds, the engine can be restarted in a short time if the engine fails to start, and the same operation as normal protection can be performed when the engine fails to start N times.

Effects of the Invention Frequency detection means that detects the frequency of the output of the back electromotive voltage detection circuit and causes the operation means to stop the operation of the non-commutated DC motor when the detected frequency becomes higher than a certain frequency;
N-ary counting means for counting the number of times the frequency detecting means operates; first timer means generating a signal after a predetermined time after the detecting means operates; and an output signal of the N-ary counting means or an output of the protection detection circuit. By providing a second timer means that generates a signal after a predetermined period of time after the signal is generated, if the commutatorless DC motor fails to start, it can be stopped once and then restarted in a short time. Therefore, a quick start is possible. Furthermore, if the engine fails to start N times in a row, it can be determined that there is an abnormality and a protective operation can be performed.

11 A=・

[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 flowchart explaining the operation of FIG. 1, and FIG. 3 is a conventional control device for a non-commutated DC motor. FIG. 4 is a flowchart explaining the operation of FIG. 3. 1... DC power supply, 2... Semiconductor communication data device, 3... Commutatorless DC motor, 6...
...Back electromotive voltage detection circuit, 7a... Operating means, 7b... Second timer means, 7c...
Frequency detection means, 7d...-N-ary counting means, 7e
...First timer means, 9...Protection detection means. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

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 protection detection circuit that detects abnormal operation of the semiconductor commutator and generates a protection signal; and a protection detection circuit that controls and disables the semiconductor switching element of the semiconductor commutator device. an operating means for operating the commutator motor; and a frequency for detecting the frequency of the output of the back electromotive voltage detection circuit and causing the operating means to stop the operation of the non-commutated DC motor when the detected frequency becomes higher than a certain frequency. a detection means, an N-ary counting means for counting the number of operations of the frequency detecting means, a first timer means for generating a signal after a predetermined time after the frequency detecting means operates, and an output signal of the N-ary counting means; A control device for a non-commutated DC motor, comprising: second timer means for generating a signal after a predetermined period of time after the output signal of the protection detection circuit is generated.