JPS60200794A - Overload detection protector of permanent magnet type synchronous motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an overload M detection and protection device for a Hall motor that is frequently used in office automation equipment such as a F1 knobby disk drive device.

[Prior art and its problems]

Conventionally, the following methods have been applied as motor overload detection and protection devices.

1) A method in which a temperature sensing element such as a thermistor is attached directly to the motor winding, and overload is detected from the temperature rise of the motor.

2) A method to prevent the motor from becoming overloaded in advance by providing a load current limiter circuit using current detection.

3) When the motor current reaches a certain value or more, a timer using an integrator or the like is activated to detect overload based on the duration of the overcurrent.

Whether each of the above methods 1) to 3) is often used in combination rather than singly, ○Atλ
As in the case of M-type devices, it is sometimes necessary to choose a method that is possible or simple due to dimensional constraints of the control circuit or constraints such as cost.

1) is a method that is used for feed motors or spindle motors of NC machine tools, etc., but it requires attachment to the motor windings and the addition of an interface circuit; 2); 3) is a method of indirectly detecting or preventing motor overload, and has drawbacks such as requiring separate adjustments for each motor if the capacity or model of the motor is different.

[Purpose of the invention]

The present invention provides temperature dependence of a ball element, which is one of the magnetically sensitive elements embedded in each phase of the armature winding or placed near the winding of each phase, in order to detect the motor magnetic pole position. The purpose is to detect the temperature of the motor windings using the characteristics of the motor, and when the winding temperature reaches a certain set level or lower, turn off the drive circuit to protect the motor from pre-overload operating conditions. be.

[Structure of the invention]

The overload detection protection device of the present invention compares the output of the magnetic pole position detector at an arbitrary temperature with the output at a reference setting temperature, and detects when the temperature of the electric motor exceeds the reference setting temperature. The present invention is characterized in that it includes a 1, 1 comparison circuit that sends a signal to stop power supply to the motor.

〔Example〕

Hereinafter, the present invention will be specifically described based on embodiments shown in the drawings.

First, a configuration example of a ball motor drive circuit according to the present invention will be explained with reference to FIG. In the figure, (1) is a main circuit, (1b) is an inverter section that converts a DC voltage into a square wave AC voltage, and (1d) is a voltage control section that controls the amplitude of the inverter output voltage. (2) represents a Hall motor, (2a) to (2c) are armature windings, and (2)
d) is a rotor composed of permanent magnets, (3a) to (3c
) is a Hall element. The control circuit of the drive section includes a shaping circuit (7) for shaping the waveform of the output signal from the ball element;
The output signal of the same shaping circuit (7) is 12o.

The distribution signal circuit (8) converts the energization square wave signal and the distribution signal is current amplified to create the main circuit in-hark fit (
(lb) 1~Heas drive circuit for turning on and off the transistor (9), speed setting value and Kukoje failure (4)
Speed control that controls the motor speed by driving the transistor in the main circuit voltage control (111 section (1a)) according to the amount of deviation from the speed feedback signal from the motor, and controlling the amplitude of the square wave AC voltage applied to the motor. It consists of an overload detection circuit (6) for detecting motor overload (1; j) from the output voltage of the ball element.

Figure 2 shows the signal waveforms of each part of the two driving units and the control circuit, where (al~(C) is the ball element output voltage, i
dl~(fl or its waveform-shaped signal, (g'r~fU and (jl~(1)) represent the distribution signal.

Next, the overload (ij detection circuit (6)) according to the present invention will be explained.
) (6a) and a comparison circuit (6b), one of which can be constructed by the circuit illustrated in FIG. Also, ii' of the speed control circuit (10)
(ifl[l can be configured with the circuit illustrated in FIG. 4. In this figure, (10a) is a speed amplifier, (
10b) is an analog switch.

The ball element is generally commercially available 1nsb, In
It is made using semiconductor elements such as As or GaAs. Among these, ball elements using InSb (indium antimony) have a large output voltage, but have the disadvantage of a large temperature coefficient. -For example, when driving with constant current, f'71 is -1 to --2%/°C!
The degree coefficient is °C.

The present invention attempts to measure temperature as well as magnetic flux by utilizing this large 6114 degree coefficient. For example, as shown in FIG. 5, the ball element output voltage at 25°C is
Assuming that the temperature coefficient is -1.5%/'c, the output voltage decreases to 62.5% at 50°C. Therefore, if a voltage of 62.5% of the absolute value circuit output voltage (output voltage of operational amplifier 2IC) is applied to the negative (-) input terminal of comparator 31C in FIG. When 1'< 50°C, the output of comparator 31C becomes H (high logic level) because it becomes higher than the nail voltage +=C, and when Go >50'c, it becomes L (low logic level). . Furthermore, if the output format of the comparator is an open collector node, the main circuit's voltage control transistor can be connected directly to the gate of the 1-live transistor, as shown in Figure 3.
When T>50°C, the DC main power supply can be turned off to protect the motor from overload +'r:j condition. When the overload becomes ij - ('IX!r degree becomes 10η1, the peak value of the output [al, (bl, tc+) in Fig. 2 decreases, so the output of 2IC in Fig. 3 also decreases, and therefore the output of 3IC The output of is 17.

In the above embodiment, the absolute value circuit section of the overload detection circuit is a three-phase full wave as shown in FIG. 3, but the circuit can be simplified by using a full sum wave. Moreover, without using a rectifier circuit, it is also possible to perform overload protection by detecting the change in the peak value of any of the waveforms shown in FIG. The same applies to outputs that have temperature dependence.

〔Effect of the invention〕

As described above, the present invention provides the following effects.

■) Since the pole element, which is a detector of the motor magnetic pole position, is also used as a temperature detector, it is possible to install a temperature detection element such as a thermistor in the winding as a means of detecting motor overload. ” There is no need to go.

2) Pole motors generally have a capacity of several watts to several watts, and there are cases where the control circuit board and the morph section are integrated. Therefore, according to the present invention, since temperature rise is detected and protected, not only the motor but also the peripheral ICs are protected, which helps improve the reliability of the entire device.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the structure of the pole motor according to the present invention (dynamic circuit and protection circuit), Figure 2 is a waveform diagram showing the waveforms of each part, and Figure 3 is a concrete diagram of the overload iJ detection circuit. Figure 4 is a circuit diagram showing a specific example of the configuration of the 1, 1 speed control circuit, Figure 5 is a circuit diagram showing a specific example of the configuration of the pole element temperature
．． FIG. (1): Main circuit (2) Two-pole motor (3a) to (3
c): Pole element (4); Tachogear non-rake (5): Speed setting device (6)
, Overload detection circuit Raku patent applicant Yaskawa Electric Co., Ltd. Agent Tebori
Benefit (1 idiot) Figure 1 Figure 2

Claims (1)

[Claims] 1. In a control device for a permanent magnet type synchronous motor equipped with a magnetic pole position detector, the output of the magnetic pole position detector at an arbitrary ak degree is compared with the output at a reference set temperature. An overload detection and protection device for a permanent magnet type synchronous motor, comprising a comparison circuit that sends a signal to stop power supply to the motor when the temperature of the motor exceeds the reference setting temperature. .