JP2650652B2 - Motor control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for controlling an AC motor.

[0002]

2. Description of the Related Art An AC motor connected to a commercial power supply via a motor drive circuit and an instruction value-revolution speed characteristic are set in advance, and an instruction value of a magnitude at which a target rotation speed is obtained is transmitted to the motor drive circuit. There is a motor control device having a microcomputer that performs the control.

Since the power supply voltage of the commercial power supply fluctuates depending on the use condition of the electric appliance, even if the microcomputer sends an instruction value for obtaining the target rotation speed to the motor drive circuit, the actual rotation speed is always constant. The above-mentioned motor control device has a disadvantage that it does not always reach the target rotation speed.

As a technique for solving this drawback, the following is conventionally known. Using an automatic voltage controller,
Always control the commercial power supply voltage to the rated voltage. A rotation speed sensor for detecting the rotation speed is attached to the AC motor, and the microcomputer adjusts the magnitude of the indicated value so that the detected rotation speed reaches the target rotation speed.

[0005]

The former technique requires a large-scale automatic voltage control device and requires a high manufacturing cost. The latter technique has a high manufacturing cost because the rotational speed sensor is expensive.

An object of the present invention is to provide an inexpensive motor control device capable of maintaining the rotation speed of an AC motor at a target rotation speed even when the power supply voltage of a commercial power supply fluctuates.

[0007]

In order to solve the above problems, the present invention provides a power supply circuit having a power transformer having a primary side connected to a commercial power supply and a rectifier connected to a secondary side of the power transformer. An AC motor that operates on commercial power, a proportional valve and a solenoid valve that operate on DC, a motor drive circuit that supplies power to the AC motor with an amount of electricity proportional to the magnitude of the indicated value, and an operation from the rectifying side of the power supply circuit Power is supplied, and a proportional valve circuit that feeds the proportional valve with an amount of current proportional to the magnitude of the proportional valve instruction value, and operating power is supplied from the rectifying side of the power supply circuit, and a solenoid valve opening signal is supplied. The solenoid valve circuit that supplies power to the solenoid valve accordingly, and an instruction value-speed characteristic when the voltage of the commercial power supply is a rated voltage is set in advance, and the instruction value of a magnitude at which a target rotation speed is obtained is set to the motor drive. When sent to the circuit A microcomputer that transmits the proportional valve indication value and the solenoid valve opening signal; a voltage detection circuit that detects a rectified voltage of the power supply circuit and outputs a detection signal to the microcomputer. And a storage means for storing an adjustment rectified voltage at the time of an adjustment test in which the voltage of the commercial power supply is a rated voltage and the current consumption of the proportional valve circuit and the solenoid valve circuit is a predetermined value.
Calculate the current voltage value of the commercial power supply from (current detected rectified voltage during operation)-(the adjusted rectified voltage), the current proportional valve instruction value and the presence / absence of the valve opening signal, and (rated voltage) A configuration is adopted in which the larger the (calculated voltage value of the commercial power supply) is, the larger the indicated value is.

[0008]

[Action] The rectified voltage of the power supply circuit is the voltage fluctuation of the commercial power supply,
And the magnitude of the proportional valve instruction value sent by the microcomputer and the presence or absence of the valve opening signal (the magnitude of the current consumption of the proportional valve circuit and the solenoid valve circuit).

The microcomputer calculates (current rectified voltage during operation)-(adjusted rectified voltage):
The current commercial power supply voltage value is calculated from the current proportional valve instruction value and the presence or absence of the valve opening signal, and as the (rated voltage)-(calculated commercial power supply voltage value) increases, the instruction value increases. to correct.

When (rated voltage)-(calculated voltage value of commercial power supply) is negative, correction is made so that the proportional valve indication value becomes smaller. Further, when (rated voltage)-(calculated voltage value of commercial power supply) = 0, the proportional valve instruction value is not corrected.

[0011]

According to the present invention, the microcomputer calculates (current detected rectified voltage during operation)-(adjusted rectified voltage);
The current commercial power supply voltage value is calculated from the current proportional valve instruction value and the presence or absence of the valve opening signal, and as the (rated voltage)-(calculated commercial power supply voltage value) increases, the instruction value increases. Has been corrected. For this reason, even if the power supply voltage of the commercial power supply fluctuates, the rotation speed of the AC motor can be maintained at a rotation speed close to the target rotation speed. Further, since the voltage detection circuit does not directly detect the voltage of the commercial power supply, the configuration of the voltage detection circuit can be simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The motor control device A for controlling the convection fan of the hot air heater has an AC motor 1, a motor drive circuit 2 for driving the AC motor 1, and an instruction value 31 for the motor drive circuit 2.
A microcomputer 3 for sending to the
It includes a proportional valve circuit 5, an electromagnetic valve circuit 6, and a voltage detection circuit 7.

The AC motor 1 is an AC motor operated by a commercial power supply 10 of AC-100V, such as a shade motor or a condenser motor, and has one terminal 11 connected to one end 101 of the commercial power supply 10 and the other terminal connected thereto. 12 is connected to one output terminal 21 of the motor drive circuit 2.

The motor drive circuit 2 composed of a triac, a phototriac coupler, etc.
Is connected to the other end 102 of the commercial power supply 10 to supply the AC motor 1 with an amount of electricity proportional to the value of the indicated value 31.

At the time of the adjustment test, an accurate AC-100V is applied to the hot air heater between the commercial power supply 10 and the commercial power supply 10 via an external power supply voltage stabilizer, and the electric load is set to a predetermined state (for example, (Electromagnetic safety valve open, proportional valve current 100mA)
In this state, the microcomputer 3 sets the divided voltage 7
The rectified voltage 420 detected based on 1 E ² PROM
(Step s0) stored in (storage means).

During the heating operation, the warm air heater is directly connected to the commercial power source 10 and the microcomputer 3
As shown in the flowchart of FIG. 2, (current detected rectified voltage)-(adjusted rectified voltage when AC-100 V is applied) and the current operating state (instruction) of the proportional valve circuit 5 and the solenoid valve circuit 6 The current commercial power supply voltage value is calculated from the value of the value 32 and the presence / absence of transmission of the valve opening signal 33) (step s1), and (rated voltage = 100V) − (calculated current commercial power supply (Step s2).

In step s1, the current proportional valve circuit 5
And the operating state of the solenoid valve circuit 6 (specifically, the indicated value 32
The reason for taking into account the size of the valve and whether or not the valve opening signal 33 is transmitted) is that the rectified voltage 420 of the power supply circuit 4 also changes depending on the operating states of the proportional valve circuit 5 and the solenoid valve circuit 6.

The power supply circuit 4 includes a power supply transformer 41 having the primary winding 411 connected to the commercial power supply 10, a silicon bridge diode 42 connected to the secondary winding 412, a smoothing capacitor 43, and a rectified output. (+ 15V, +
5V).

The proportional valve circuit 5 is provided with a proportional valve 51 for controlling the amount of gas passing therethrough, and an electric power for driving the proportional valve 51 supplied from the power supply circuit 4 (rectified voltage 420), and an instruction value 32 transmitted by the microcomputer 3 And a proportional valve drive circuit 52 that drives the proportional valve 51 based on It should be noted that, as the indicated value 32 is larger, the current consumption is larger, so that the voltage drop of the rectified output 420 is larger.

The electromagnetic valve circuit 6 receives the electromagnetic safety valve 61 and power for driving the electromagnetic safety valve 61 from the power supply circuit 4 (rectified voltage 420), and receives the electromagnetic safety valve 61 based on the valve opening signal 33 sent from the microcomputer 3. And an electromagnetic valve drive circuit 62 for driving the motor. Since the current flows at the time of valve opening when the valve opening signal 33 is transmitted, the rectified voltage 42
0 decreases.

The voltage detection circuit 7 is composed of, for example, two resistors connected in series, and inputs a divided voltage 71 to an input port of the microcomputer 3. Note that the microcomputer 3 calculates the rectified voltage 420 based on the obtained divided voltage 71.

The motor control device A of this embodiment has the following advantages. [A] The microcomputer 3 applies an accurate AC-100V at the time of the adjustment test, and adjusts the rectified voltage at the time of adjusting the current consumption of the proportional valve circuit 5 and the solenoid valve circuit 6 to a predetermined value. Based on the difference between the current detected rectified voltage and the current operating state of the electric load, the current voltage value of the commercial power supply is calculated, and the rated voltage of 100 V and the calculated current voltage value of the commercial power supply 10 are calculated. Considering the difference,
The instruction value 31 sent to the motor drive circuit 2 is corrected.

For this reason, even if the power supply voltage of the commercial power supply 10 fluctuates due to the start or stop of use of other electric appliances during the heating operation, the rotation speed of the AC motor 1 is set to a rotation speed close to the target rotation speed. It can be maintained and the amount of hot air blown out does not fluctuate.

[A] Since the voltage detection circuit 7 is configured to input the rectified voltage 420 and divide the voltage, the divided voltage 71 can be directly input to the microcomputer 3 and the configuration of the voltage detection circuit 7 is simplified. It can be.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of a motor control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the motor control device.

[Explanation of symbols]

 A Motor controller 1 AC motor 2 Motor drive circuit 3 Microcomputer 4 Power supply circuit 5 Proportional valve circuit 6 Solenoid valve circuit 7 Voltage detection circuit 10 Commercial power supply 31 Indicated value 41 Power supply transformer 42 Silicon bridge diode (rectifier) 411 Primary winding ( Primary side) 412 Secondary winding (secondary side) 420 Rectified voltage

Claims (1)

(57) [Claims] A power transformer having a primary side connected to a commercial power supply.
And a rectifier connected to the secondary side of the power transformer.
A power supply circuit, an AC motor operated by a commercial power supply, a proportional valve and a solenoid valve operated by DC, a motor drive circuit that supplies an electric current to the AC motor in proportion to a magnitude of an indicated value, and the power supply circuit. Operation power is supplied from the rectifying side of
Power is supplied to the proportional valve with the amount of electricity proportional to the value of the valve indication value
A proportional valve circuit for actuating power is supplied from the rectifier side of the power supply circuit, the electromagnetic
An electromagnetic valve circuit for supplying power to the electromagnetic valve according to a valve opening signal
And the indicated value when the voltage of the commercial power supply is a rated voltage-
Rotational speed characteristic is preset, both an indication of the magnitude of the target rotational speed is obtained is sent to the motor drive circuit, before
A motor control device comprising: a microcomputer for transmitting the proportional valve indication value and the solenoid valve opening signal.
Te detects the rectified voltage of the power supply circuit, the micro competent
A voltage detection circuit for outputting a detection signal to Yuta, the proportional valve circuit and the voltage of the commercial power source to the rated voltage
At the time of an adjustment test in which the current consumption of the solenoid valve circuit is set to a predetermined value.
Definitive and storage means for storing the adjusted time rectified voltage provided, the microcomputer (current detection rectified voltage during operation) - (the adjustment
Current rectified voltage) , the current proportional valve instruction value and the presence or absence of the valve opening signal to calculate the current voltage value of the commercial power supply , and (rated voltage)-(calculated voltage value of the commercial power supply) is large.
Degree, the motor control device and correcting as the instruction value increases.