CN102996420A - Controller of compressor - Google Patents

Abstract

In the compressor control device of the present invention, when the DC motor is in operation, the setting time of the timer is set based on the motor current detected by the motor current detection means. When the set time is reached, the rotation speed of the DC motor is increased, so that the rotation speed control according to the load can be realized. When it is judged that the load of the refrigerator is large, the operation is quickly performed at high speed. When the load is small, it can rotate at a low speed to realize energy-saving operation.

Description

compressor control unit

technical field

The present invention relates to an inverter circuit for driving a motor through a switching element that performs PWM control, and particularly relates to a control device suitable for driving a compressor installed in a refrigerator or the like.

Background technique

In the prior art, in the control device of this compressor, there is a control device that operates at a rotational speed determined according to the difference between the set temperature of the refrigerator and the temperature in the box (for example, refer to Japanese Patent Application Laid-Open No. 62-009165). ).

Patent Document 1 is a control device that determines the operating speed of a compressor based on the preset temperature and the temperature inside the refrigerator to operate the compressor.

Hereinafter, the above-mentioned conventional compressor control device will be described with reference to the drawings.

Fig. 3 is a circuit diagram of a conventional compressor control device described in Japanese Patent Application Laid-Open No. 62-009165. Fig. 4 is a flowchart of a conventional compressor control device. The operation of increasing and decreasing the rotational speed of the DC motor will be described below.

In FIG. 3 , the temperature detection mechanism 1 in the box detects the temperature in the box, and the set temperature detection mechanism 2 detects the set temperature. The control mechanism 3 is connected with the temperature detection mechanism 1 and the set temperature detection mechanism 2, and is determined according to the difference between the temperature in the box detected by the temperature detection mechanism 1 and the set temperature detected by the temperature detection mechanism 2 The operating speed of the compressor 8. For example, when the temperature in the box is 5°C higher than the set temperature, it is determined to be 3600 rpm, when the temperature is 5°C to 2°C, it is determined to be 2400 rpm, and when the temperature is 2°C to -2°C, it is determined to be 1600 rpm. In the case of less than 2 ° C, it is determined to be 0 revolutions.

The AC/DC conversion mechanism 4 is connected to the commercial power supply 5 to convert the commercial AC voltage into a DC voltage. The input of the inverter circuit 6 is connected to the AC/DC conversion mechanism 4 , and the output of the inverter circuit 6 is connected to the DC motor 7 .

The DC motor 7 is incorporated in a compressor 8 (not shown) for cooling a refrigerator or the like.

The inverter circuit 6 is composed of six switching elements T1, T2, T3, T4, T5, and T6, and the six switching elements are connected in a three-phase bridge.

The inverter control unit 10 is connected to the control unit 3 and drives the DC motor 7 at a rotation speed determined by the control unit 3 .

The inverter control mechanism 10 includes a position detection mechanism 11, a commutate (rectification) mechanism 12, a speed control mechanism 13, a speed calculation mechanism 14, a set speed detection mechanism 15, a speed comparison mechanism 16, a synthesis mechanism 17 and a driving mechanism 18.

The position detection mechanism 11 detects the position of the rotor according to the counter electromotive force of the DC motor 7 , and sends position detection signals to the commutation (transition) mechanism 12 , the rotation speed control mechanism 13 and the rotation speed calculation mechanism 14 .

The commutation mechanism 12 sends a driving commutation pulse to the synthesis mechanism 17 according to the output of the position detection mechanism 11 .

The rotational speed calculation unit 14 calculates the rotational speed of the DC motor 7 by counting the position detection signal of the position detection unit 11 for a certain period or measuring the pulse interval, and sends the operating rotational speed of the DC motor 7 to the rotational speed comparison unit 16 .

On the other hand, the set rotational speed detection means 15 detects the set rotational speed sent from the control means 3 and sends it to the rotational speed comparison means 16 .

The rotation speed comparison means 16 sends 0 rotations to the rotation speed control means 13 as long as the set rotation speed is 0 rotations, and the DC motor 7 keeps stopping.

In addition, as long as it is other than 0 revolutions, for example, 1600 revolutions, 1600 revolutions is sent to the rotational speed control means 13 . The rotational speed control means 13 starts the DC motor 7 as long as the DC motor 7 is stopped.

Then, the rotational speed comparison means 16 compares the rotational speed of the DC motor 7 from the rotational speed calculation means 14 with the set rotational speed from the set rotational speed detection means 15 . When the rotational speed of the DC motor 7 is lower than the set rotational speed, an output to increase the duty ratio is output to the rotational speed control means 13 . As a result, the rotation speed control means 13 increases the duty ratio to increase the voltage applied to the DC motor 7 to increase the rotation speed.

When the rotational speed of the DC motor 7 is higher than the set rotational speed, an output to decrease the duty ratio is output to the rotational speed control means 13 . As a result, the rotational speed control means 13 reduces the duty ratio, reduces the voltage applied to the DC motor 7, and thereby lowers the rotational speed.

The combining mechanism 17 outputs the logic AND of the output of the reversing mechanism 12 and the output of the rotational speed control mechanism 13 to the driving mechanism 18 , and the driving mechanism 18 drives the inverter circuit 6 .

In the compressor control device configured as described above, the operation of increasing and decreasing the rotational speed of the DC motor 7 incorporated in the compressor 8 will be described below using FIG. 4 .

First, the control mechanism 3 determines the operating speed of the DC motor 7 from the difference between the temperature in the box detected by the temperature detection mechanism 1 and the set temperature detected by the set temperature detection mechanism 2, and uses it as the set speed inversely. The converter control mechanism 10 sends.

The inverter control mechanism 10 inputs a set rotational speed in STEP1.

In STEP2, the set rotation speed detection means 15 judges whether the input set rotation speed is 0 rotations, and if it is 0 rotations, it stops the DC motor 7 in STEP3. If the set speed is not 0 revolutions, then enter STEP4 to judge whether the DC motor 7 is in a stopped state. Here, if the DC motor 7 is in a stopped state, start control is performed in STEP 5 to start the DC motor 7 . After the start-up control finishes, enter STEP6, and the rotating speed calculation mechanism 14 calculates the rotating speed of the DC motor 7 according to the signal of the position detecting mechanism 11. The calculation result of the rotational speed of the DC motor 7 calculated by the calculation means 14 is compared.

When the calculation result of the rotational speed in STEP8 is smaller than the set rotational speed, the process proceeds to STEP9, in order to increase the rotational speed, the rotational speed control means 13 increases the duty ratio.

Enter STEP10 when the speed calculation result in STEP8 is not smaller than the set speed, judge whether the speed calculation result is larger than the set speed, enter STEP11 under the large situation, in order to make the speed drop, the speed control mechanism 13 makes the duty ratio drop.

In this way, it is controlled so that the rotation speed becomes the set rotation speed, and it operates at an appropriate rotation speed according to the load in the tank.

Contents of the invention

However, in the above-mentioned conventional structure, there is a problem that the rotation speed of the compressor cannot be determined in a refrigerator that does not have a control mechanism for determining the operation rotation speed of the compressor based on the difference between the interior temperature and the preset temperature.

In order to solve this problem, the invention has the following control method: use a thermostat that is turned on/off (ON/OFF) according to the temperature in the box, and input a running or stop signal to the inverter control mechanism. As long as the inverter control mechanism is activated When the operation signal is input, the operation of the compressor is started at a low speed, and the operation speed is increased after a certain period of time has elapsed. However, the thermostat information is only on/off temperature and cannot determine the proper operating speed.

The present invention is a technology to solve the above-mentioned conventional problems, and its object is to operate at an appropriate rotation speed according to the load in the cabinet even in a refrigerator that does not have a control mechanism that determines the operating speed of the compressor based on the difference between the temperature in the cabinet and the set temperature. run.

In order to solve the above-mentioned problems in the prior art, the control device of the compressor of the present invention operates the compressor at a constant rotational speed, detects the load of the refrigerator by detecting the motor current at this time, and based on the detection result of the load of the refrigerator, The time to increase the rotation speed of the compressor is set, so it can be operated at an appropriate rotation speed according to the load in the tank.

The compressor control device of the present invention can operate at an appropriate rotational speed according to the load of the refrigerator. For example, when it is judged that the load of the refrigerator is large, it can quickly perform high-speed rotation and perform energy-saving operation at low speed when the load is small.

Description of drawings

FIG. 1 is a circuit diagram of a compressor control device according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart showing the operation of the compressor control device according to Embodiment 1. FIG.

FIG. 3 is a circuit diagram of a conventional compressor control device described in Patent Document 1. FIG.

FIG. 4 is a flowchart showing the operation of the conventional compressor control device.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, in all the following drawings, the same or corresponding elements are given the same reference numerals, and overlapping descriptions are omitted.

The first invention is a control device that increases the rotational speed of the compressor with time in response to a signal to operate or stop the compressor, and in this control device, operates the compressor at a constant rotational speed during operation. The load of the compressor is detected by detecting the motor current at this time, and the time for increasing the rotational speed of the compressor is changed according to the detection result of the load of the compressor. According to the above configuration, it is possible to set the rising time of the rotational speed of the compressor according to the load.

The second invention is a control device comprising: an operation/stop detection mechanism for detecting an operation signal or a stop signal of a compressor; and a rotation speed setting for setting an operation rotation speed of the compressor based on an output from the operation/stop detection mechanism. Mechanism; an inverter circuit for operating the motor assembled into the above-mentioned compressor; a position detection mechanism for detecting the position of the rotor of the above-mentioned motor and generating a position detection signal; based on the output of the above-mentioned position detection mechanism, the action of the above-mentioned inverter circuit is determined, and the output is changed A reversing mechanism to the pulse; in order to make the rotation speed of the above-mentioned compressor variable, adjust the duty ratio as the ratio of the conduction time in the carrier cycle to control the speed control mechanism of the voltage; according to the output of the above-mentioned reversing mechanism and The output of the above-mentioned rotation speed control means drives the above-mentioned inverter circuit; the rotation speed calculating means calculates the rotation speed of the above-mentioned motor based on the output of the above-mentioned position detection means; The constant rotational speed is compared with the rotational speed of the above-mentioned motor calculated by the above-mentioned rotational speed calculating means, and is output to the above-mentioned rotational speed control means so that the rotational speed of the above-mentioned motor becomes a set rotational speed; a motor current detecting means for detecting the motor current of the above-mentioned inverter circuit; and A timer that sets a rotation speed increase time based on a motor current value detected by the motor current detection unit, and outputs a rotation speed increase signal to the rotation speed setting unit when the set time is reached. According to the above configuration, the rotation speed increase time can be set for each operation rotation speed, and the rotation speed increase time of the compressor can be set according to the load.

The content of the third invention is that in the first or second invention, the control device for the compressor that controls the refrigerator can set the rotational speed increase time of the compressor according to the load. Therefore, not only the effects of the first or second invention can be obtained, but also appropriate operation of the refrigerator can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to this embodiment.

(implementation mode 1)

FIG. 1 is a circuit diagram of a compressor control device according to Embodiment 1 of the present invention. FIG. 2 is a flowchart showing the operation of the compressor control device according to Embodiment 1. FIG. Hereinafter, a method of determining the operating speed of the compressor according to the load state and operating the compressor will be described.

In FIG. 1 , taking the case where the compressor 108 is installed in the refrigerator as an example, the following embodiment will describe the control of the refrigerator.

The thermostat 101 detects the temperature inside the box and performs on/off operation.

The AC/DC conversion mechanism 104 is connected to the commercial power supply 105, and converts the commercial AC voltage into a DC voltage. The input of the inverter circuit 106 is connected to the AC/DC conversion mechanism 104 , and the output of the inverter circuit 106 is connected to the DC motor 107 .

The DC motor 107 is incorporated in a compressor 108 for cooling a refrigerator or the like.

The inverter circuit 106 is composed of six switching elements T1, T2, T3, T4, T5, and T6, and the six switching elements are connected in a three-phase bridge.

The inverter control means 110 is connected to the thermostat 101, and operates the DC motor 107 in the ON state, and stops the DC motor 107 in the OFF state.

The inverter control mechanism 110 includes a position detection mechanism 111, a reversing mechanism 112, a speed control mechanism 113, a speed calculation mechanism 114, a running/stop detection mechanism 115, a speed comparison mechanism 116, a synthesis mechanism 117, a driving mechanism 118, and a speed setting mechanism. mechanism 120 and timer 121.

The position detection unit 111 detects the position of the rotor based on the counter electromotive force of the DC motor 107 , and sends position detection signals to the reversing unit 112 , the rotation speed control unit 113 and the rotation speed calculation unit 114 .

The commutation mechanism 112 sends a driving commutation pulse to the synthesis mechanism 117 according to the output of the position detection mechanism 111 .

The rotational speed calculation means 114 calculates the rotational speed of the DC motor 107 by counting the position detection signal of the position detection means 111 for a certain period or measuring the pulse interval, and sends the operating rotational speed of the DC motor 107 to the rotational speed comparison means 116 .

On the other hand, the operation/stop detection means 115 detects an operation or stop signal sent from the thermostat 101 and sends it to the rotation speed setting means 120 .

The rotational speed setting means 120 sends the operating rotational speed to the rotational speed comparison means 116 . At this time, if the signal from the thermostat 101 is stop, 0 rotation is sent to the rotation speed comparison mechanism 116 , and if it is an operation signal, a signal of the minimum rotation speed, for example, 1600 rotation is sent.

The rotational speed comparator 116 sends a signal to the rotational speed control means 113 to operate at 1600 rpm, and the rotational speed control means 113 operates the DC motor 107 at 1600 rpm.

The rotational speed comparing means 116 compares the rotational speed from the DC motor 107 with the set rotational speed from the rotational speed setting means 120 . When the rotational speed of the DC motor 107 is lower than the set rotational speed, an output to increase the duty ratio is output to the rotational speed control means 113 . Accordingly, the rotational speed control means 113 increases the duty ratio and increases the voltage applied to the DC motor 107 to increase the rotational speed. Furthermore, when the rotational speed of the DC motor 107 is higher than the set rotational speed, the rotational speed comparator 116 outputs an output to decrease the duty ratio to the rotational speed control means 113 . Accordingly, the rotation speed control means 113 reduces the duty ratio and reduces the voltage applied to the DC motor 107 to lower the rotation speed.

The synthesis mechanism 117 outputs the logical AND of the output of the reversing mechanism 112 and the output of the rotation speed control mechanism 113 to the drive mechanism 118 . The driving mechanism 118 drives the inverter circuit 106 .

In addition, the motor current during 1600-rotation operation for a certain period of time is input to the timer 121 from the motor current detection means 122 . Also, when the motor current is large, it is judged that the load is large, and the time until the rotation speed increases is set earlier (earlier), and when the motor current is small, it is judged that the load is small, and the time until the rotation speed is increased is set later. (later).

This is because when the DC motor 107 is operated at a constant rotational speed, the motor current increases when the load is heavy, and decreases when the load is light, so that the magnitude of the load can be determined from the motor current.

In the refrigerator, when the temperature of food in the box is high or the outside air temperature is high, the load on the compressor 108 becomes heavy, and in this case, it is necessary to perform cooling rapidly by rotating at a high speed. Conversely, when the food in the box is sufficiently cooled or the outside temperature is low, the load on the compressor 108 becomes light, and high-speed rotation is not required at this time, and low-speed rotation is performed for energy-saving operation.

The timer 121 sends a signal indicating to increase the rotational speed to the rotational speed setting mechanism 120 when the set time has elapsed, and the rotational speed setting mechanism 120 increases the rotational speed accordingly.

Next, the operation of determining the operating speed of the compressor according to the load state and operating the DC motor 107 will be described using FIG. 2 .

First, the inverter control means 110 receives a signal from the thermostat 101 at STEP 101, and judges whether the input is an operation signal or a stop signal.

If it is a stop signal, it proceeds to STEP114, clears the accumulated time of the timer 121, and stops the DC motor 107 at STEP115.

If it is an operation signal, the DC motor 107 is operated at 1600 revolutions in STEP102.

Next, in STEP 103 , the motor current at 1600 revolutions is detected after a certain period of time has elapsed from the start of the operation.

Next, in STEP 104, it is determined whether or not the motor current is 0.5 A or less, for example. If it is below 0.5A, set the set value of the timer time to 30 minutes in STEP105. If it exceeds 0.5A, enter STEP106 to judge whether it is below 0.6A. If it is below 0.6A, set the set value of the timer time to 20 minutes in STEP107. If it exceeds 0.6A, then enter STEP108, and set the set value of the timer time to 10 minutes. In addition, after the setting of STEP105,107,108, the timer 121 starts measurement of the elapsed time.

Next, enter STEP109, the inverter control mechanism 110 receives the signal from the thermostat 101, and judges whether the input is an operation signal or a stop signal. If it is a stop signal, it proceeds to STEP114, clears the accumulated time of the timer 121, and stops the DC motor 107 at STEP115. If it is an operation signal, it is judged in STEP110 whether it has reached the set time of the timer 121 or not. If the set time is not reached, the timer 121 is used to accumulate time in STEP113. If the set time has arrived, then at STEP111, the timer 121 sends a signal to the speed setting mechanism 120, so that the speed rises to, for example, 2400 revolutions, and the speed setting mechanism 120 sends a signal to the speed comparison mechanism 116, so that it can run at 2400 revolutions . Along with this, the rotational speed comparator 116 sends a signal to the rotational speed control means 113 so that the duty ratio increases.

Then, in STEP112, the timer 121 is cleared, and the process returns to STEP109.

Therefore, the magnitude of the load is determined by measuring the motor current at a constant rotational speed. Furthermore, when the load is heavy, the rotation speed of the DC motor 107 can be increased early, and when the load is light, the DC motor 107 can be operated at a low speed without increasing the rotation speed, so that the operation according to the load can be realized.

In addition, the increase in the operating speed of the DC motor 107 from the lowest rotational speed of 1600 revolutions has been described, but the motor current can be similarly measured for the operation from 1600 revolutions to 2400 revolutions, and the increase can be further increased. The time to 3600 rpm varies accordingly with the load.

In addition, in the DC motor 107, since the motor current when the load is constant is the same even when the rotational speed changes, the rotational speed at which the motor is operated at a constant rotational speed can be arbitrarily selected.

As described above, the compressor control device of the present invention can control the rotation speed of the compressor according to the load even if there is no control mechanism for the refrigerator. Or it is useful for cold storage control used at home.

Claims (3)

1. A control device for a compressor, which increases the operating speed of the compressor over time according to an operating signal or a stop signal of the compressor, the control device is characterized in that: Make the compressor run at a certain speed during operation, and detect the load of the compressor by detecting the motor current at this time, A time to increase the rotation speed of the compressor is set based on a detection result of the load of the compressor. 2. A control device for a compressor, comprising: A run/stop detection mechanism that detects the running signal or stop signal of the compressor; a rotational speed setting means for setting an operating rotational speed of the compressor based on an output from the operation/stop detection means; an inverter circuit for operating an electric motor incorporated into said compressor; a position detection mechanism that detects the position of the rotor of the motor and generates a position detection signal; A commutation mechanism that determines the action of the inverter circuit based on the output of the position detection mechanism and outputs a commutation pulse; In order to make the rotation speed of the compressor variable, a rotation speed control mechanism that adjusts a duty ratio that is a ratio of an on-time within a carrier cycle and controls a voltage; a driving mechanism for operating the inverter circuit according to the output of the reversing mechanism and the output of the rotational speed control mechanism; a rotation speed calculation mechanism for calculating the rotation speed of the motor according to the output of the position detection mechanism; a rotational speed comparing means that compares the set rotational speed set by the rotational speed setting means with the rotational speed of the motor calculated by the rotational speed calculation means, and outputs it to the rotational speed control means so that the rotational speed of the motor become the set speed; a motor current detection mechanism that detects a motor current of the inverter circuit; and A timer that sets a rotation speed increase time based on a motor current value detected by the motor current detection unit, and outputs a rotation speed increase signal to the rotation speed setting unit when the set time is reached. 3. The control device of the compressor according to claim 1 or 2, characterized in that: It is a device for controlling the refrigerator.

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