JP2001073944A - Driving device for linear compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device for linear compressor to make a frequency thereof correspond to a resonance frequency of a mechanical system even when the spring constant of a gas spring is changed by a change of load condition and the like. SOLUTION: This device is provided with an inverter 102 for driving a motor winding 103 of the linear compressor for compressing refrigerant by reciprocating motion of a piston, an alternating current power source 100 on a primary side of the inverter 102, a phase detecting circuit 104 for detecting a difference in phase between voltage of the alternating current power source 100 and current passing through the motor winding 103 of the linear compressor, and a calculating controlling part 108 and a base drive circuit 106 for controlling driving frequency of the inverter 102 according to the difference of the phase detected by the phase detecting circuit 104. A resonance frequency of a mass system is thereby always maintained even against load change and highly efficient driving can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a linear compressor for compressing a refrigerant by reciprocating a piston.

[0002]

2. Description of the Related Art A conventional linear compressor is disclosed, for example, in Japanese Utility Model Laid-Open No. 2-145678. A conventional linear compressor will be described with reference to FIG. The pressure command generator 30 gives a pressure command to the first addition amplifier 31, and the first addition amplifier 31
The pressure command and the pressure value detected by the pressure detector 41 are added and amplified to generate an error signal.
And adds and amplifies with the frequency signal generated by the frequency signal generator 33 to output to the pulse signal generator 34. The pulse signal generator 34 generates a pulse signal based on the signal output from the second summing amplifier 32 and supplies the pulse signal to the power controller 35. The power controller 35 uses the power supplied by the AC power source 36 based on the signal generated by the pulse signal
7 is driven. The compressor 38 sucks, compresses, and discharges the refrigerant in the pressure tank 39. The pressure detector 41 detects the pressure of the refrigerant discharged from the pressure tank 39 and outputs a signal to the first summing amplifier 31. As described above, when a difference between the pressure indicated by the pressure command generator 30 and the pressure of the pressure tank 39 detected by the pressure detector 41 occurs by using the conventional vibrating compressor, the second addition amplifier 32 Controls the signal output given to the pulse signal generator 34 to operate the linear compressor 40.

[0003]

However, in the linear compressor driving device using the prior art, a voltage of a constant frequency is applied to the winding of the linear compressor from the power supply device. There is a problem in that the constant of the gas spring changes, a deviation occurs between the actual operation frequency and the resonance frequency, and the efficiency is extremely reduced.

Accordingly, an object of the present invention is to provide a drive device for a linear compressor that always matches the resonance frequency of the mechanical system even when the constant of the gas spring changes due to a change in load conditions or the like.

[0005]

According to a first aspect of the present invention, there is provided a linear compressor driving apparatus according to the present invention, comprising: a linear compressor for reciprocating a piston to compress a refrigerant; an inverter for driving the linear compressor; A secondary-side AC power supply, a phase detection device that detects a phase difference between a voltage of the AC power supply and a current flowing through a motor winding of the linear compressor, and driving the inverter according to the phase difference detected by the phase detection device. Means for controlling the frequency. The drive device for a linear compressor according to the present invention according to claim 2, wherein the linear compressor that reciprocates a piston to compress the refrigerant, an inverter that drives the linear compressor, an AC power supply on a primary side of the inverter, and the AC A phase detection device that detects a phase difference between a voltage of a power supply and a current flowing through the motor winding of the linear compressor and a current flowing through the motor winding of the linear compressor, and a mechanical system according to the phase difference detected by the phase detection device. It is characterized by comprising means for matching the resonance frequency and means for adjusting the phase angle of the current so that the current flowing through the motor winding of the linear compressor is minimized. According to a third aspect of the present invention, there is provided a linear compressor driving device for controlling an inverter for driving a motor winding of a linear compressor and a driving frequency of the inverter according to a phase difference between a power supply voltage and a current flowing through the motor winding. And means for performing the operation. According to a fourth aspect of the present invention, in the driving device for a linear compressor according to any one of the first to third aspects, the energization timing at the time of suction and compression of the linear compressor by a voltage induced in the motor winding. Is controlled.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A linear compressor driving apparatus according to first and third embodiments of the present invention drives an inverter according to a phase difference between a voltage of an AC power supply and a current flowing through a motor winding of the linear compressor. It controls the frequency. When the load increases with the frequency of the output voltage of the inverter kept constant at the resonance frequency, the resonance frequency of the spring mass system changes, and the phase difference between the AC voltage on the primary side of the inverter and the current flowing through the linear motor changes. Increase. Therefore, according to the present embodiment, the resonance frequency is always maintained with respect to a load change, and high-efficiency driving is possible.

A driving device for a linear compressor according to a second embodiment of the present invention adjusts the frequency of the inverter to the resonance frequency of the spring mass system, and adjusts the current phase angle until the motor current detected by the phase detecting device becomes minimum. Is provided, the frequency of the inverter is made to match the resonance frequency of the spring mass system according to the phase difference detected by the phase detection device, and the current phase angle is adjusted until the motor current is minimized. The resonance frequency is always maintained against a load change, and high-efficiency driving is possible.

A fourth embodiment of the present invention is directed to a linear compressor driving apparatus according to the first to third embodiments, wherein the energizing timing at the time of suction / compression of the linear compressor by a voltage induced in the motor winding. Is controlled, the resonance frequency can be made to match the resonance frequency of the spring mass system of the linear compressor.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a driving device of a linear compressor according to an embodiment of the present invention. As shown in the figure, an AC voltage from an AC power supply 100 is converted to DC by a converter circuit 101 and supplied to an inverter 102. In the inverter 102, the base of the power transistor receives the drive signal from the base drive circuit 106, converts the direct current supplied from the converter circuit 101 into alternating current, passes an alternating current to the winding 103 of the linear motor, and drives the linear compressor. . The linear compressor compresses the refrigerant by reciprocating the piston. The phase detection circuit 104 detects the phase difference between the voltage of the AC power supply 100 and the current flowing through the winding 103 of the linear compressor and the motor current, and the detection result is supplied to the arithmetic and control unit 108. Since a voltage is induced in the winding 103 of the linear compressor, the induced voltage is detected by the induced voltage detection circuit 105, and the timing of energization of the winding 103 during suction and compression is detected. Supply the detection result. The control calculation unit 108 calculates signals from the phase detection circuit 104 and the induced voltage detection circuit 105, controls the driving of the base drive circuit 106 according to the calculation result, and supplies the drive signal of a predetermined frequency and voltage to the inverter 102. Supply. The inverter 102 includes an arithmetic control unit 108
And outputs the specified frequency and voltage to the winding 103 of the linear compressor based on the frequency and the output instruction signal from the controller. The phase detection circuit 104 includes an AC power source 1 on the primary side.
00 and a phase difference between the current flowing through the winding 103 of the linear motor and the current flowing through the winding 103 of the linear motor.
08 and the energization timing are controlled to match the resonance frequency of the spring mass system of the linear compressor. Reference numeral 107 denotes an electrolytic capacitor coupled to the input side of the inverter 102.

FIG. 2 is a diagram showing a drive control flow of the linear compressor according to the first embodiment. In step 200, the voltage of the AC power supply 100 is detected, and in step 201, the phase difference of the current flowing through the winding 103 of the linear compressor is detected. In step 202, the phase difference between the power supply voltage and the motor current detected by the phase detection circuit 104 is calculated. Note that this phase difference detection is performed by the arithmetic control unit 10.
8 can also be calculated. In step 203, the phase difference between the power supply voltage and the motor current detected by the phase detection circuit 104 is determined, and the process is divided into three steps. When the phase of the motor current is advanced from the phase of the power supply voltage with respect to the power supply voltage, the driving frequency is reduced by ２０４ in step 204.
Lower by f. If the phases of the power supply voltage and the motor current are the same, the process proceeds to step 205, and the current drive frequency is maintained. If the phase of the motor current is delayed compared to the phase of the power supply voltage, the drive frequency is increased by Δf.
After these steps, the system returns to step 200 again and repeats the same operation.

Next, the degree of increase and decrease of the driving frequency is shown in FIG.
This will be described in more detail. FIG. 3 is a diagram illustrating a phase difference characteristic between a power supply voltage and a motor current with respect to a resonance state between a mechanical system and a driving frequency. When the phase of the motor current is delayed as compared with the phase of the power supply voltage at each time of detecting the phase difference between the power supply voltage and the motor current described in FIG.
In the case where the phase difference of the motor current with respect to the power supply voltage is increased until the phase difference of the motor current becomes 0, and conversely, the phase of the motor current is ahead of the phase of the power supply voltage, The drive frequency is set at a set value every predetermined time,
That is, the phase difference is reduced until the phase difference between the power supply voltage and the current becomes zero. Therefore, when the drive frequency and the resonance frequency of the spring mass system of the mechanical system are resonating, the phase difference between the power supply voltage and the motor current is in phase. In this way, by adjusting the drive frequency, the phase of the power supply voltage and the motor current can be controlled, so that the drive frequency of the linear motor is maintained at the resonance frequency of the piston, and the resonance frequency is maintained even if the load fluctuates. The efficiency does not decrease.

Next, another embodiment will be described with reference to FIG. FIG. 4 is a diagram showing a drive control flow of the linear compressor of the present embodiment. In step 250, the microcomputer of the arithmetic control unit 108 calculates the phase difference between the power supply voltage of the AC power supply 100 and the motor current flowing through the winding 103 of the linear compressor. Note that the calculation can be performed by the phase detection circuit 104 instead of the calculation control unit 108. In step 251, the phase difference between the power supply voltage and the motor current calculated in step 250 is compared. If the power supply voltage and the motor current are in phase, the drive frequency is maintained in step 252. Next, the routine proceeds to step 255, where the phase angle between the voltage applied to the winding 103 of the linear motor and the current flowing through the winding 103 is calculated. In step 256, the value of the current flowing through the winding 103 of the linear motor is detected by the phase detection circuit 104, and in step 257, the motor current is compared with a predetermined set value. If the phase angle is maintained and the motor current is larger than the set value, the current phase angle is set to △ in step 259.
Control is performed such that the motor current is minimized by increasing or decreasing by r every predetermined time. Thereafter, the process returns to step 250.

FIG. 5 is a characteristic diagram of the motor current with respect to the current phase angle. As can be seen from the figure, if the motor phase is controlled so that the motor current is minimized by adjusting the current phase angle, the drive frequency and the mechanical system resonance frequency match, so that highly efficient operation is possible. On the other hand, if the phase of the power supply voltage leads the phase of the motor current in step 251, step 2
At 53, the drive frequency is increased by Δf. If the phase of the power supply voltage is behind the phase of the motor current, the drive frequency is decreased by Δf at step 254. After the drive frequency is increased or decreased, the process returns to step 250.

[0014]

As described above, according to the present invention, the phase difference between the power supply voltage and the current flowing through the winding of the linear compressor is calculated, and the drive frequency is increased, the current status is maintained, or reduced according to the phase difference. Thus, the drive frequency of the linear motor is maintained at the resonance frequency of the piston, and the resonance frequency can be maintained even when the load varies. Therefore, highly efficient operation is possible. Further, in the present invention, the energization phase angle is appropriately maintained so that the motor current is minimized, so that a more efficient operation can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a linear compressor driving device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the linear compressor driving device according to the embodiment;

FIG. 3 is a diagram showing a phase difference between a power supply voltage and a motor current with respect to a drive frequency according to the embodiment.

FIG. 4 is a flowchart illustrating an operation of a driving device for a linear compressor according to another embodiment of the present invention.

FIG. 5 is a characteristic diagram of a motor current with respect to a current phase angle according to the embodiment.

FIG. 6 is a block diagram showing an example of a conventional linear compressor pressure control device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 AC power supply 101 Converter circuit 102 Inverter 103 Linear compressor winding 104 Phase detection circuit 105 Induced voltage detection circuit 106 Inverter base drive circuit 107 Electrolytic capacitor 108 Operation control unit

Continuing from the front page (72) Inventor Yoshiro Tsuchiyama 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. BB32 BB43 CC02 CC98 CC99 5H540 AA10 BB09 EE02 EE07 EE08 FC02 FC03

Claims (4)

[Claims] 1. A linear compressor for reciprocating a piston to compress a refrigerant, an inverter for driving the linear compressor, an AC power supply on a primary side of the inverter, a voltage of the AC power supply and a motor winding of the linear compressor. A linear compressor drive device comprising: a phase detection device that detects a phase difference of a current flowing through a line; and a unit that controls a drive frequency of the inverter according to the phase difference detected by the phase detection device. . 2. A linear compressor for compressing a refrigerant by reciprocating a piston, an inverter for driving the linear compressor, an AC power supply on a primary side of the inverter, a voltage of the AC power supply and a motor winding of the linear compressor. A phase detection device that detects a phase difference of a current flowing through a line and a current flowing through a motor winding of the linear compressor; a unit that matches a resonance frequency of a mechanical system according to the phase difference detected by the phase detection device; Means for adjusting the phase angle of the current so that the current flowing through the motor winding of the compressor is minimized. 3. An inverter for driving a motor winding of a linear compressor, and means for controlling a driving frequency of the inverter according to a phase difference between a power supply voltage and a current flowing through the motor winding. Linear compressor drive. 4. The power supply timing at the time of suction / compression of the linear compressor is controlled by a voltage induced in the motor winding.
A driving device for a linear compressor according to any one of the above.