WO2024075451A1

WO2024075451A1 - Drive device for vibrating-type compressor

Info

Publication number: WO2024075451A1
Application number: PCT/JP2023/032040
Authority: WO
Inventors: 正夫生井
Original assignee: 澤藤電機株式会社
Priority date: 2022-10-05
Filing date: 2023-08-31
Publication date: 2024-04-11
Also published as: JP2024054672A

Abstract

An MCU (5) detects a first zero cross position (A) of induced voltage generated in an electromagnetic coil (224) of a vibrating-type compressor (20) during a first dead time (DT1) from when an upper-stage transistor (TR21) is turned off to when a lower-stage transistor (TR22) is turned on. The MCU (5) controls an on/off cycle of the upper-stage transistor TR (21) and the lower-stage transistor (TR22) on the basis of the first zero cross position (A). Further, the MCU (5) causes the first dead time (DT1) to be longer than a second dead time (DT2) at the starting time.

Description

Vibration compressor drive

The present invention relates to a drive device for a vibration compressor.

A known example of a drive device for the above-mentioned vibration compressor is described in Patent Document 1. The drive device for the vibration compressor described in Patent Document 1 includes an inverter that converts direct current to alternating current by alternately turning on an upper switch and a lower switch, and a frequency tracking circuit that controls the on/off of the upper switch and the lower switch based on the current input to the vibration compressor. The frequency tracking circuit has a peak hold circuit, and controls the upper switch and the lower switch according to the second peak of the current.

It is also possible to control the upper and lower switches based on the zero-cross position where the induced voltage input to the vibration compressor is 0V other than the second peak. However, there is an issue that the amplitude of the vibration compressor is small at start-up, making it difficult to detect the zero-cross position, and the vibration compressor cannot be operated efficiently.

　In addition, the drive device for the vibration compressor in Patent Document 1 had the problem that the frequency tracking circuit needed to be changed depending on the type of vibration compressor.

Japanese Patent Publication No. 2001-178149

The present invention was made in consideration of the above-mentioned circumstances, and its purpose is to provide a drive device for a vibration compressor that can easily detect the first zero cross position, efficiently operate the vibration compressor, and reduce power consumption.

The present invention also provides a drive device for a vibration compressor that can perform frequency tracking regardless of the type of vibration compressor.

In order to achieve the above-mentioned object, a drive device for a vibrating compressor according to the present invention is characterized by the following [1] to [18].
[1]
an inverter having a first switch element and a second switch element connected in series with each other, which converts direct current into alternating current by alternately turning on the first switch element and the second switch element, and supplies the converted alternating current to an electromagnetic coil of a vibration type compressor;
a first zero-cross position detection unit that detects a first zero-cross position of an induced voltage generated in the electromagnetic coil of the vibration type compressor during a first period from when the first switch element is turned off to when the second switch element is turned on;
an inverter control unit that controls an on/off period of the first switch element and the second switch element based on the first zero cross position,
The inverter control unit sets the first period to be longer than a second period from when the second switch element is turned off to when the first switch element is turned on.
[2]
In the drive device of the vibration type compressor according to [1],
the inverter control unit makes the first period longer than the second period during a certain startup period immediately after power is turned on, and makes the first period equal to the second period after the startup period.
[3]
In the drive device of the vibration type compressor according to [2],
a second zero-cross position detector that detects a second zero-cross position of an induced voltage generated in the electromagnetic coil of the vibration compressor during the second period;
An abnormal vibration detection unit that detects abnormal vibration of the vibration type compressor,
After the start-up period,
a third period is half a period between one of the first zero cross position and the second zero cross position detected in an n-th period (n is an integer) and the one of the first zero cross position and the second zero cross position detected in an n+1-th period;
a period between the one of the first zero cross position and the second zero cross position detected in the nth period and the other of the first zero cross position and the second zero cross position detected in the nth period is defined as a fourth period,
an abnormal vibration detection unit that detects the abnormal vibration of the vibrating compressor when a difference between the third period and the fourth period exceeds a predetermined value;
an abnormal vibration escape unit that escapes from the abnormal vibration state detected by the abnormal vibration detection unit.
[4]
In the drive device of the vibration type compressor according to [2],
a second zero-cross position detector that detects a second zero-cross position of an induced voltage generated in the electromagnetic coil of the vibration compressor during the second period;
An abnormal vibration detection unit that detects abnormal vibration of the vibration type compressor,
After the start-up period,
a third period is half a period between one of the first zero cross position and the second zero cross position detected in an n-th period (n is an integer) and the one of the first zero cross position and the second zero cross position detected in an n+1-th period;
a period between the one of the first zero cross position and the second zero cross position detected in the nth period and the other of the first zero cross position and the second zero cross position detected in the nth period is defined as a fourth period,
an abnormal vibration detection unit that detects the abnormal vibration of the vibrating compressor when an integrated value obtained by integrating the difference between the third period and the fourth period for each first predetermined period exceeds a predetermined threshold value a first predetermined number of times in succession;
an abnormal vibration escape unit that escapes from the abnormal vibration state detected by the abnormal vibration detection unit.
[5]
In the drive device of the vibration type compressor according to [3],
The abnormal vibration escape unit is a drive device for a vibration compressor that reduces an on-duty of the first switch element and the second switch element to damp resonance of a spring system of the vibration compressor, thereby escaping from the abnormal vibration.
[6]
In the drive device of the vibration type compressor according to [4],
After the startup period, the abnormal vibration detection unit
a third period is a half of a period between the second zero cross position detected in the nth cycle and the second zero cross position detected in the n+1th cycle;
a fourth period is defined as a period between the second zero cross position detected in the nth period and the first zero cross position detected in the nth period;
determining the difference between the third period and the fourth period;
The first predetermined period is 10 waves to 50 waves, with one cycle from the second zero cross position detected in the nth cycle to the second zero cross position detected in the n+1th cycle being one wave.
It is a driving device for a vibrating compressor.
[7]
In the drive device of the vibration type compressor according to [4],
the predetermined threshold is set so that a ratio of the difference with respect to the third period is 0.23% to 0.59%.
[8]
In the drive device of the vibration type compressor according to [4],
The first predetermined number of times that the predetermined threshold value is exceeded consecutively is 3 to 10 times.
[9]
In the drive device of the vibration type compressor according to [3],
The abnormal vibration escape unit is a driving device for a vibration type compressor that reduces the on-duty of the first switch element and the second switch element to a value between 0% and 50%.
[10]
In the drive device of the vibration type compressor according to [3],
The abnormal vibration escape unit is a drive device for a vibration compressor, which varies an on/off period of the first switch element and the second switch element to vary a resonance frequency of a spring system of the vibration compressor.
[11]
In the drive device for a vibration type compressor according to any one of [3] to [10],
The inverter control unit is a drive device for a vibration-type compressor, and if the inverter control unit detects the abnormal vibration a second predetermined number of times during a second predetermined period after the abnormal vibration state is escaped by the abnormal vibration escape unit, the inverter control unit performs normal operation for a certain period thereafter.
[12]
In the drive device of the vibration type compressor according to [11],
The second predetermined period is one minute, and the second predetermined number of times is three.
[13]
In the drive device of the vibration type compressor according to [11],
The certain period is three minutes.
[14]
In the drive device of the vibration type compressor according to [1],
The inverter control unit sets the on-duty of the first switch element and the second switch element to a minimum on-duty at which an induced voltage can be detected immediately after the compressor starts operating, and then performs a soft start by gradually increasing the on-duty.
[15]
In the drive device of the vibration type compressor according to [1],
The vibration type compressor is a drive device for a vibration type compressor that drives a refrigerator having an upward-opening lid.
[16]
an inverter having a first switch element and a second switch element connected in series with each other, which converts direct current into alternating current by alternately turning on the first switch element and the second switch element, and supplies the converted alternating current to an electromagnetic coil of a vibration type compressor;
and a microcomputer that controls the on/off timing of the first switch element and the second switch element based on an input from the vibration type compressor, and outputs a drive pulse in accordance with a fluctuation in a resonance frequency of a movable part including a coil and a piston of the vibration type compressor.
[17]
In the drive device of the vibration type compressor according to [16],
The input of the vibration type compressor is an induced voltage.
[18]
In the drive device of the vibration type compressor according to [16],
The input of the vibration type compressor is an induced current.

According to the drive device for a vibrating compressor having the configuration [1] above, by making the first period greater than the second period, even when the amplitude of the vibrating compressor is small, it is possible to lengthen the generation period of an induced voltage having a first zero cross position, make it easier to detect a minute first zero cross position, and operate the vibrating compressor efficiently, thereby reducing power consumption.
According to the driving device for a vibrating compressor having the configuration [2] above, the first period can be made greater than the second period during startup when the amplitude of the vibrating compressor is small, and startup can be performed stably.
According to the driving device for a vibrating compressor having the configurations [3] and [4] above, it is possible to detect abnormal vibrations and escape from the abnormal vibrations without installing a vibration sensor or the like.
According to the driving device for a vibrating compressor having the configuration [5] above, the resonance of the spring system of the vibrating compressor is damped, and it is possible to escape from abnormal vibration.
According to the vibrating compressor driving device having the configurations [6] to [8] above, abnormal vibration can be detected.
According to the vibrating compressor drive device having the configurations [9] and [10] above, it is possible to escape from abnormal vibration.
According to the drive device for a vibrating compressor having the configurations [11] to [13] above, excessive stoppage of a refrigerator driven by the vibrating compressor can be prevented and cooling performance can be maintained.
According to the driving device for a vibrating compressor having the configuration described above in [14], the vibrating compressor can be started stably after power is turned on.
According to the drive device for the vibrating compressor having the configuration [15] above, even when the refrigerator is restarted and the cooling performance is reduced due to a drop in output of the vibrating compressor, cool air is unlikely to leak, so that the cooling performance can be maintained.
According to the driving device for a vibrating compressor having the configurations [16] to [18] above, frequency tracking is possible regardless of the type of vibrating compressor.

The present invention provides a vibration compressor that is easy to detect the first zero cross position, can operate efficiently, and can reduce power consumption.

The present invention has been briefly described above. Furthermore, the details of the present invention will become clearer by reading the following description of the mode for carrying out the invention (hereinafter referred to as "embodiment") with reference to the attached drawings.

FIG. 1 is a circuit diagram showing an embodiment of a drive device for a vibrating compressor according to the present invention. FIG. 2 is a schematic cross-sectional view of the vibrating compressor shown in FIG. FIG. 3 is a time chart of the inverter output voltage, the piston position, the timer count value, the on/off states of the upper transistor and the lower transistor, the first induced voltage pulse, the first detection range, the first induced voltage pulse in the first detection range, the second induced voltage pulse, the second detection range, and the second induced voltage pulse in the second detection range, during duty-up and steady state of the drive device of the vibrating compressor shown in FIG. 1 . FIG. 4 is a flowchart showing the procedure of the main process executed by the MCU shown in FIG. FIG. 5 is a flowchart showing the procedure of the output period processing executed by the MCU shown in FIG. FIG. 6 is a flowchart showing the procedure of the interrupt process executed by the MCU shown in FIG. FIG. 7 is a flowchart showing a procedure of the timer process executed by the MCU shown in FIG. FIG. 8 is a time chart showing the on/off of the power supply and the compressor current of the vibration type compressor shown in FIG. FIG. 9 is a time chart showing the on/off states of the upper and lower transistors, the output voltage of the inverter, and the first detection range when the driving device for the vibrating compressor shown in FIG. 1 is started up. FIG. 10 is a time chart of the output voltage of the inverter for explaining the abnormal vibration detection process. FIG. 11 is a flowchart showing a procedure of the abnormal vibration detection process executed by the MCU shown in FIG.

Specific embodiments of the present invention are described below with reference to the figures.

FIG. 1 is a circuit diagram showing one embodiment of a drive device for a vibration compressor of the present invention. The vibration compressor 20 is for driving a refrigerator, for example, mounted on an automobile or a refrigerator in which the container itself is a refrigerator, and operates on a low AC voltage. In this embodiment, the vibration compressor 20 drives a refrigerator having a top-opening lid.

The drive device 1 (hereinafter simply referred to as the "drive device") for the vibration compressor 20 shown in FIG. 1 drives the vibration compressor 20 using a battery 30 such as that installed in an automobile when the commercial AC power source 40 is not connected to the plug 14. The drive device 1 is a device that drives the vibration compressor 20 using the commercial AC power source 40 when the commercial AC power source 40 is connected to the plug 14.

First, before describing the configuration of the drive unit 1, the vibration compressor 20 will be described with reference to Figure 2. The vibration compressor 20 includes a sealed container 21, a compressor body 22 housed in the sealed container 21, and a pair of vibration-proof springs 23, 23 provided between the sealed container 21 and the compressor body 22 from above and below. The compressor body 22 includes a cylindrical external core 221, a cylindrical internal core 222 inserted into the external core 221, a permanent magnet 223 disposed on the outer surface of the internal core 222, an electromagnetic coil 224 disposed in an annular gap formed by the permanent magnet 223 and the external core 221 so as to be able to vibrate up and down, a piston 225 connected to the electromagnetic coil 224, and a pair of

resonant springs

226, 226 that bias the piston 225 from above and below. The vibration compressor 20 supplies AC power to the electromagnetic coil 224 to vibrate the piston 225 connected to the electromagnetic coil 224, and flows low-pressure refrigerant into the sealed container 21 and discharges the compressed high-pressure refrigerant.

As shown in FIG. 1, the drive device 1 includes an AC/DC converter 2, a DC/DC converter 3, diodes D1 and D2, an inverter 4, an MCU (Main Control Unit) 5 as a computer, a PC (Personal Computer) communication unit 6, an induced voltage detection unit 7, a driver 8, an input voltage detection unit 9, a DC/DC converter IC 10, a DC voltage detection unit 11, a DC/DC converter 12, and a fan 13.

AC/DC converter 2 converts AC power from commercial AC power source 40 into the desired DC power. DC/DC converter 3 boosts DC battery voltage VB supplied from battery 30 and converts it into the desired DC power. DC/DC converter 3 includes Zener diodes DZ1 and DZ2 for surge protection, a filter circuit 31 that removes high-frequency components from battery voltage VB, a backflow prevention circuit 32, coil L1, transistor TR1, diode D2, capacitors C11 and C12, and capacitors C21 and C22.

One end of the coil L1 is connected to the positive electrode of the battery 30 via the filter circuit 31, and is supplied with the battery voltage VB from which high-frequency components have been removed. The transistor TR1 is composed of an N-channel field-effect transistor. The drain of the transistor TR1 is connected to the other end of the coil L1, and the source is connected to ground. The anode of the diode D2 is connected to the other end of the coil L1 and the drain of the transistor TR1. The capacitors C11 and C12 are connected between one end of the coil L1 and the ground. The capacitors C21 and C22 are connected between the cathode of the diode D2 and the ground.

In the DC/DC converter 3 configured as described above, when the transistor TR1 is turned on, the voltages across the capacitors C11 and C12, which are charged to the battery voltage VB, are supplied to the capacitors C21 and C22. At this time, energy is stored in the coil L1. Next, when the transistor TR1 is turned off, the sum of the voltages across the capacitors C11 and C12 and the coil L1 is supplied to the capacitors C21 and C22. The voltages across the capacitors C21 and C22 are supplied to the inverter 4 in the next stage as DC voltages converted (boosted) by the DC/DC converter 3.

Diode D1 is connected between AC/DC converter 2 and inverter 4. To explain in more detail, the anode of diode D1 is connected to the AC/DC converter 2 side and the cathode is connected to the inverter 4 side, and the DC power converted by AC/DC converter 2 is supplied to inverter 4 via diode D1.

Diode D2 is connected between DC/DC converter 3 and inverter 4. To explain in more detail, the anode of diode D2 is connected to the DC/DC converter 3 side, and the cathode is connected to the inverter 4 side, and the DC power converted by DC/DC converter 3 is supplied to inverter 4 via diode D2.

The inverter 4 converts the DC power source converted by the AC/DC converter 2 or the DC/DC converter 3 into AC power source and supplies it to the electromagnetic coil 224 of the vibration compressor 20. The inverter 4 includes an upper transistor TR21 as a first switch element and a lower transistor TR22 as a second switch element connected in series between the cathodes of the diodes D1, D2 and the ground, capacitors C31, C32 for cutting the DC component, and a smoothing coil L2.

The upper transistor TR21 and the lower transistor TR22 are composed of N-channel field effect transistors. The upper transistor TR21 has a drain connected to the cathodes of the diodes D1 and D2, and a source connected to the drain of the lower transistor TR22. The lower transistor TR22 has a drain connected to the source of the upper transistor TR21, and a source connected to ground. The upper transistor TR21 and the lower transistor TR22 are connected to the DC/DC converter IC10, which will be described later, and are alternately turned on and off.

One end of each of the capacitors C31 and C32 is connected to the source of the upper transistor TR21 and the drain of the lower transistor T22, and the other end is connected to one end of the coil L2. The other end of the coil L2 is connected to one end of the electromagnetic coil 224 of the vibration compressor 20. The other end of the electromagnetic coil 224 is connected to ground.

Next, the on/off of the upper transistor TR21 and the lower transistor TR22 during duty up and steady state, the output voltage VOUT of the inverter 4, and the position of the piston 225 will be described with reference to FIG. 3. In FIG. 3, the first and second detection ranges are indicated by diagonal lines. As shown in the figure, the upper transistor TR21 and the lower transistor TR22 are alternately turned on. Between the on period of the upper transistor TR21 and the on period of the lower transistor TR22, there is provided a first dead time DT1 (=first period) and a second dead time DT2 (second period) during which both the upper transistor TR21 and the lower transistor TR22 are off.

When the upper transistor TR21 is on and the lower transistor TR22 is off, the source voltage of the upper transistor TR21 (the drain voltage of the lower transistor TR22) becomes the input voltage VIN, and the capacitors C31 and C32 are charged. The input voltage VIN is a direct current voltage supplied from the AC/DC converter 2 or the DC/DC converter 3. At this time, the output voltage VOUT supplied to the electromagnetic coil 224 is a positive voltage obtained by subtracting the voltages across the capacitors C31 and C32 from the input voltage VIN. When a positive voltage is supplied to the electromagnetic coil 224, a force is generated in the electromagnetic coil 224 that moves the piston 225 to the top dead center, and the piston 225 moves toward the top dead center beyond the neutral position where the upper and lower resonant springs 226 are balanced.

Next, when both the upper transistor TR21 and the lower transistor TR22 are turned off, a negative counter electromotive force (counter electromotive force) is generated in the output voltage VOUT. Even after both the upper transistor TR21 and the lower transistor TR22 are turned off, the piston 225 continues to move toward the top dead center due to inertia, which generates a positive induced voltage in the output voltage VOUT. When the piston 225 reaches the top dead center and stops, the output voltage VOUT becomes 0V. After reaching the top dead center, the piston 225 moves toward the neutral position on the bottom dead center side due to the biasing force of the resonant spring 226, which generates a negative induced voltage in the output voltage VOUT.

Next, when the upper transistor TR21 is turned off and the lower transistor TR22 is turned on, the source voltage of the upper transistor TR21 (the drain voltage of the lower transistor TR22) becomes ground (0V), and the capacitors C31 and C32 are discharged. At this time, the output voltage VOUT supplied to the electromagnetic coil 224 is a negative voltage obtained by subtracting the voltage across the capacitors C31 and C32 from 0V. When a negative voltage is supplied to the electromagnetic coil 224, a force is generated in the electromagnetic coil 224 that moves the piston 225 to the bottom dead center, and the piston 225 moves beyond the neutral position toward the bottom dead center.

Next, when both the upper transistor TR21 and the lower transistor TR22 are turned off, a positive counter-electromotive force is generated in the output voltage VOUT. Even after both the upper transistor TR21 and the lower transistor TR22 are turned off, the piston 225 continues to move toward the bottom dead center due to inertia, which generates a negative induced voltage in the output voltage VOUT. When the piston 225 reaches the bottom dead center and stops, the output voltage VOUT becomes 0V. After reaching the bottom dead center, the piston 225 moves toward the neutral position on the top dead center side due to the biasing force of the resonant spring 226, which generates a positive induced voltage in the output voltage VOUT.

The MCU 5 is a well-known computer that operates according to a program, and controls the entire drive device 1. In this embodiment, the MCU 5 has a built-in temperature sensor. The PC communication unit 6 is an interface for communicating with a PC, and is controlled by the MCU 5. The induced voltage detection unit 7 generates a first induced voltage pulse and a second induced voltage pulse (see FIG. 3) that are at H level when the output voltage VOUT of the inverter 4 is a positive voltage or a negative voltage, and outputs them to the MCU 5. The driver 8 outputs drive pulses to the gates of the upper transistor TR21 and the lower transistor TR22 according to the control of the MCU 5. The input voltage detection unit 9 detects the input voltage VIN input to the inverter 4, and supplies the AD value converted by AD conversion to the MCU 5. The MCU 5 controls the duty cycle based on the voltage of the input voltage detection unit 9 so that the power supplied to the vibration compressor 20 is constant.

The DC/DC converter IC10 detects the input voltage VIN, i.e., the output voltage of the DC/DC converter 3, and controls the on/off of the transistor TR1 so that the input voltage VIN becomes the desired voltage. While an enable signal is being output from the MCU 5, the DC/DC converter IC10 controls the on/off of the transistor TR1 so that the input voltage VIN becomes the desired DC voltage, and stops the on/off control of the transistor TR1 when the output of the enable signal from the MCU 5 is stopped.

The DC voltage detection unit 11 is connected to the output voltage VOUT2 of the AC/DC converter 2 via a diode D3. The DC voltage detection unit 11 detects the output voltage VOUT2, and outputs the AD-converted AD value to the MCU 5. The cathode of the diode D3 is connected to the cathode of the diode D4. The anode of the diode D4 is connected to one end of the coil L1 and is supplied with the battery voltage VB. The DC/DC converter 12 has the cathodes of the diodes D3 and D4 connected thereto, and converts the output voltage VOUT2 and the battery voltage VB into the desired DC voltage (for example, 11 V) and outputs it to the fan 13.

Next, the operation of the drive device 1 configured as described above will be described below with reference to the flowchart shown in FIG. 4. First, when the power is turned on, the MCU 5 performs initialization and fault diagnosis (S1, S2). Next, the MCU 5 takes in the AD value output from the DC voltage detection unit 11 (S3) and performs AC priority processing (S4).

In the AC priority process, the MCU 5 determines whether or not the commercial AC power supply 40 is connected to the plug 14 based on the AD value acquired in S3. The AC/DC converter 2 outputs an output voltage VOUT2 higher than the battery voltage VB. If the AD value acquired in S3 is higher than the battery voltage VB, the MCU 5 determines that the commercial AC power supply 40 is connected to the plug 14, and stops outputting the permission signal to the DC/DC converter IC 10. While the permission signal is stopped, the DC/DC converter IC 10 stops controlling the transistor TR1 and does not perform the boost operation. As a result, when the commercial AC power supply 40 is connected to the plug 14, the boost operation of the DC/DC converter 3 is stopped, and the vibrating compressor 20 is driven by the commercial AC power supply 40.

On the other hand, if the AD value captured in S3 is the battery voltage VB, the MCU 5 determines that the commercial AC power supply 40 is not connected to the plug 14, and outputs an enable signal to the DC/DC converter IC 10. While the enable signal is being output, the DC/DC converter IC 10 controls the transistor TR1 and performs a boost operation. As a result, when the commercial AC power supply 40 is not connected to the plug 14, the DC/DC converter 3 performs a boost operation, and the vibrating compressor 20 is driven by the battery 30.

Then, the MCU 5 performs communication processing with, for example, a PC or a controller (S5), and performs fan processing to control the fan 13 (S6). Thereafter, the MCU 5 functions as an inverter control unit, and performs output cycle processing to set the on-duty and output cycle of the upper transistor TR21 and the lower transistor TR22 (S7). The output cycle processing will be described later. Next, the MCU 5 functions as an abnormal vibration detection unit, and performs abnormal vibration detection processing (S8), and then returns to S2 again. The abnormal vibration detection processing will also be described later.

First, the output period processing will be described with reference to FIG. 5. First, the MCU 5 sets the on-duty of the upper transistor TR21 and the lower transistor TR22 (S71). In S71, the MCU 5 detects the ambient temperature using the built-in temperature sensor and sets the on-duty according to the ambient temperature. Specifically, the MCU 5 sets the on-duty so that it is large when the ambient temperature is high and small when the ambient temperature is low.

Next, the MCU 5 determines whether the first zero cross position A is greater than a reference (S72). This first zero cross position A will be described with reference to FIG. 3. The first zero cross position A is the position (timing) at which the piston 225 reaches top dead center, and is the position at which the induced voltage generated in the electromagnetic coil 224 becomes 0V during the first dead time DT1 from when the upper transistor TR21 turns off to when the lower transistor TR22 turns on. To explain in more detail, the MCU 5 repeatedly performs timer processing that counts up from 0 to 1023. The first zero cross position A is the count value by the timer processing when the induced voltage reaches 0V.

The time it takes to count from 0 to 1023 is roughly equal to the resonance period of the resonant spring 226. However, the resonance period of the moving part including the electromagnetic coil 224 and the piston 225 changes due to factors such as the temperature of the resonant spring 226 and load fluctuations. For this reason, in this embodiment, the MCU 5 fine-tunes the output period (on/off period) of the upper transistor TR21 and the lower transistor TR22 based on the first zero-cross position A, and performs frequency tracking control so that the moving part including the electromagnetic coil 224 and the piston 225 vibrates at the resonance frequency of the resonant spring 226.

Returning to the flowchart of FIG. 5, if the first zero cross position A is greater than the reference (Y in S72), the MCU 5 determines that the currently set output period is shorter than the resonance period of the resonance spring 226, and lengthens the next output period slightly (S73), before proceeding to S74. On the other hand, if the first zero cross position A is equal to or smaller than the reference (N in S72), the MCU 5 immediately proceeds to S74. In S74, the MCU 5 determines whether the first zero cross position A is smaller than the reference.

If the first zero cross position A is smaller than the reference (Y in S74), the MCU 5 determines that the currently set output period is longer than the resonance period of the resonance spring 226, shortens the next output period slightly (S75), and then proceeds to S76. On the other hand, if the first zero cross position A is equal to the reference (N in S74), the MCU 5 immediately proceeds to S76. Next, the MCU 5 sets the next output period to the period adjusted in S73 and S75 (S75), and ends the output period processing.

A specific example of the output period set by the above output period processing will be described with reference to FIG. 3. The reference for the first zero cross position A is "512". In FIG. 3, the first zero cross position A detected in the first timer processing is equal to the reference, so the MCU 5 does not change the next output period T12. The first zero cross position A detected in the next timer processing is "511", which is smaller than the reference, so the MCU 5 slightly shortens the next output period T13. Furthermore, the first zero cross position A detected in the next timer processing is "513", which is larger than the reference, so the MCU 5 slightly lengthens the next output period T14.

The MCU 5 also executes the first interrupt process shown in FIG. 6 to detect the first zero cross position A. As shown in FIG. 3, the MCU 5 sets the first dead time DT1 as the first detection range. The MCU 5 determines that a zero cross has occurred when the first induced voltage pulse falls while in the first detection range, and executes the first interrupt process. In the first interrupt process, the MCU 5 functions as a first zero cross position detector, stores the count value of the timer at this time as the first zero cross position A (S9), and ends the first interrupt process.

The MCU5 also functions as an inverter control unit, and executes the timer process shown in FIG. 7, which controls the on/off of the upper transistor TR21 and the lower transistor TR22. First, the MCU5 executes the timer process at the same time as the timer starts. In the timer process, the MCU5 performs a duty output process that captures the on-duty set in the output period process (S10). Next, the MCU5 performs an output process (period) that captures the output period set in the output period process, and outputs the captured on-duty and drive pulses of the output period to the upper transistor TR21 and the lower transistor TR22 (S11).

As shown in FIG. 8, the MCU 5 executes a soft start immediately after power is applied. As shown in the figure, when the MCU 5 executes S71 in FIG. 5 at startup, for example 2 seconds after power is applied, it sets the on-duty to a predetermined minimum duty without setting the on-duty based on temperature. In this embodiment, the minimum duty is set to 5% to ensure an induced voltage above a certain level (1 V or higher).

Next, when the MCU 5 executes S71 in FIG. 5 during a duty-up period of, for example, 3 seconds after startup, it gradually increases the on-duty. After that, when the MCU 5 executes S17 in FIG. 5 during a steady state after the duty-up, it sets the on-duty according to the temperature as described above.

In addition, at startup, the compressor current flowing through the electromagnetic coil 224 is small and the amplitude of the piston 225 is small, making it difficult to detect the first zero-cross position A. Therefore, when the MCU 5 executes S11 in FIG. 7 at startup, as shown in FIG. 9, it makes the first dead time DT1 longer than the second dead time DT2 from when the lower transistor TR22 is turned off to when the upper transistor TR21 is turned on. Note that the first detection range is also indicated by diagonal lines in FIG. 9.

After that, when the MCU 5 executes S11 in FIG. 7 during duty-up and steady state, it makes the first dead time DT1 and the second dead time DT2 equal, as shown in FIG. 3.

As described above, by making the first dead time DT1 > the second dead time DT2 at startup, the first detection range can be lengthened even at startup when the amplitude of the piston 225 is small, making it easier to detect the minute first zero cross position A, allowing the vibration compressor 20 to be operated efficiently and reducing power consumption.

Next, the details of the abnormal vibration detection process described above will be explained with reference to Figures 10 and 11. The MCU 5 performs abnormal vibration detection process during normal operation, but does not perform it during duty-up or startup. The resonant spring 226 and vibration-proof spring 23 of the vibration compressor 20 vibrate abnormally due to the road conditions of the vehicle, the vehicle suspension, the vehicle installation conditions, etc., and the compressor body 22 hits the sealed container 21, generating abnormal noise (rattling sound). The abnormal vibration is transmitted to the sealed container 21 of the vibration compressor 20 and then to the piston 225, affecting the induced voltage, so the abnormal vibration detection process can detect such abnormal vibration.

To perform abnormal vibration detection processing, the MCU 5 detects the second zero cross position B. The second zero cross position B is the position (timing) at which the piston 225 reaches the bottom dead center, and is the position at which the induced voltage generated in the electromagnetic coil 224 during the second dead time DT2 becomes 0V. The second zero cross position B is the count value by the timer processing when the induced voltage reaches 0V.

The MCU5 executes a second interrupt process (not shown) to detect the second zero cross position B. As shown in FIG. 3, the MCU sets the second dead time DT2 as the second detection range. The MCU5 determines that a zero cross has occurred when the second induced voltage pulse falls while in the second detection range, and executes the second interrupt process. In the second interrupt process, the MCU5 functions as a second zero cross position detector, stores the count value of the timer at this time as the second zero cross position B, and ends the second interrupt process.

In the abnormal vibration detection process, as shown in FIG. 10, half of the period T3 between the second zero cross position B detected in the nth cycle (n is an integer) and the second zero cross position B detected in the n+1th cycle is set as a half cycle T3/2 (=third period). The period between the second zero cross position B detected in the nth cycle and the first zero cross position A detected in the nth cycle is set as a period T4 (=fourth period). The MCU 5 calculates the difference ΔT between the half cycle T3/2 and the period T4 (S801).

Next, the MCU 5 accumulates the calculated difference ΔT (S802). When the difference ΔT for 25 waves (=first predetermined period), where one wave is one cycle from the second zero cross position B detected in the nth cycle to the second zero cross position B detected in the n+1th cycle, is accumulated (Y in S803), the MCU 5 judges whether the accumulated value exceeds the threshold value (S804). The first predetermined period is a period of one wave, where one wave is one cycle from the second zero cross position B detected in the nth cycle to the second zero cross position B detected in the n+1th cycle, or a period of multiple waves. In this embodiment, the first predetermined period is set to 25 waves, but it has been experimentally found that if it is set to 10 to 50 waves, it is possible to suppress erroneous detection of abnormal vibration during normal operation. When the MCU 5 judges that the accumulated value does not exceed the threshold value (N in S804), it immediately ends the abnormal vibration detection process without detecting abnormal vibration.

When the MCU 5 determines that the integrated value exceeds the threshold (Y in S804), it determines whether the integrated value has exceeded the threshold six times in a row (=first predetermined number of times) (S805). The first predetermined number is the number of times that the integrated value exceeds the threshold consecutively, and is set to six in this embodiment. If the integrated value exceeds the threshold six times in a row (Y in S805), the MCU 5 detects abnormal vibration (S806). When calculating the integrated value of the difference ΔT for 25 waves, it has been experimentally found that false detection of abnormal vibration during normal times can be suppressed by setting a threshold value such that the ratio of the difference ΔT to the half cycle T3/2 is 0.23% to 0.59%. That is, the threshold value can be set to 25 x 0.25% x T3/2 to 25 x 0.59% x T3/2.

On the other hand, if the integrated value of the difference ΔT does not exceed the threshold value six consecutive times (N in S805), the MCU 5 does not detect abnormal vibration and immediately ends the abnormal vibration detection process.

Furthermore, when abnormal vibration is detected, if a three-minute timer that counts three minutes (= a fixed period) described below is not currently counting (N in S807), the MCU 5 executes an escape process (S808). In the escape process, the MCU 5, for example, reduces the on-duty of the upper transistor TR21 and the lower transistor TR22 to 0% to stop the operation of the vibration type compressor 20. Furthermore, the MCU 5 may, for example, vary the output period of the upper transistor TR21 and the lower transistor TR22.

Next, the MCU5 judges whether or not abnormal vibration has been detected for the third time (=second predetermined number of times) in one minute (=second predetermined period) (S809). If abnormal vibration has been detected for the third time (Y in S809), the MCU5 starts a three-minute timer (S810) and then ends the abnormal vibration detection process. On the other hand, if abnormal vibration is detected but the three-minute timer is still counting (Y in S807), the MCU5 does not perform the escape process but immediately ends the abnormal vibration detection process. The second predetermined time is the period after the abnormal vibration state is escaped, and is set to one minute in this embodiment. The second predetermined number is the number of times abnormal vibration is detected during the second predetermined period after the abnormal vibration state is escaped, and is set to three times in this embodiment. The fixed time is the period after abnormal vibration is detected the second predetermined number of times during the second predetermined period after the abnormal vibration is escaped, and is set to three minutes in this embodiment.

According to the embodiment described above, the MCU 5 accumulates the difference ΔT of 25 waves, and detects abnormal vibration when the accumulated value exceeds the threshold value six times in a row. If abnormal vibration is detected, an escape process for the abnormal vibration is performed. This makes it possible to detect abnormal vibration and escape from the abnormal vibration without installing a vibration sensor or the like.

In the above-described embodiment, the MCU 5 lowers the duty of the upper transistor TR21 and the lower transistor TR22 in the escape process. This dampens the resonance of the resonant spring 226 and the vibration-proof spring 23 of the vibration compressor 20, allowing the compressor to escape from the abnormal vibration.

In the embodiment described above, the MCU 5 varies the output periods of the upper transistor TR21 and the lower transistor TR22 in the escape process. This makes it possible to escape from abnormal vibration.

According to the above-described embodiment, if abnormal vibration is detected three times within one minute after performing the abnormal vibration escape process, the MCU 5 will not perform the escape process for three minutes. As a result, after the escape process is performed once and cooling is stopped, cooling will not be stopped for three minutes, preventing excessive stopping of the refrigerator and maintaining cooling performance.

According to the embodiment described above, the MCU 5 minimizes the on-off duty of the upper transistor TR21 and the lower transistor TR22 immediately after power is turned on, and then performs a soft start by gradually increasing the on-duty. This allows the vibration compressor 20 to start up stably after power is turned on. In addition, the current capacity of the AC/DC converter 2 can be reduced, which contributes to making the drive device smaller, lighter, and less expensive.

In the above-described embodiment, the drive unit 1 drives a refrigerator having a top-opening lid. As a result, even when the refrigerator is restarted and the cooling performance is reduced due to a drop in the output of the vibration compressor 20, the cooling performance can be maintained because cold air is unlikely to leak.

According to the embodiment described above, the MCU 5 controls the on/off timing of the upper transistor TR21 and the lower transistor TR22 to vibrate the vibration compressor 20 in accordance with the resonant frequency. This makes it possible to change the software (e.g., threshold value, etc.) depending on the type of vibration compressor 20 (e.g., type of resonant spring 226), making it possible to follow the frequency regardless of the type of vibration compressor 20.

The present invention is not limited to the above-described embodiment, and can be modified, improved, etc. as appropriate. In addition, the material, shape, dimensions, number, location, etc. of each component in the above-described embodiment are arbitrary and not limited as long as they can achieve the present invention. The above-described embodiment is not limited to top-opening lids, and can also be applied to refrigerators with front-opening doors.

In the above-described embodiment, the first predetermined period for detecting abnormal vibrations was set to 25 waves, but this is not limited to this. It has been experimentally confirmed that abnormal vibrations can be detected if the first predetermined period is set between 10 waves and 50 waves.

In addition, in the above-described embodiment, the first predetermined number of times for detecting abnormal vibrations is set to six times, but this is not limited to this. It has been experimentally confirmed that abnormal vibrations can be detected if the first predetermined number of times is set between three and ten times.

In addition, in the above-described embodiment, the MCU 5 reduces the on-duty of the upper transistor TR21 and the lower transistor TR22 to 0% in the process of escaping from abnormal vibration, but this is not limited to this. It has been experimentally confirmed that it is possible to escape from abnormal vibration by reducing the on-duty between 0% and 50%.

In the above-described embodiment, the MCU 5 controls the on/off of the upper transistor TR21 and the lower transistor TR22 based on the output voltage VOUT input to the vibration compressor 20, but this is not limited to the above. The MCU 5 may also control the on/off of the upper transistor TR21 and the lower transistor TR22 based on the current input to the vibration compressor 20. In this case, as in Patent Document 1, the MCU 5 may control the on/off of the upper transistor TR21 and the lower transistor TR22 in response to the second peak of the current.

In the above-described embodiment, the upper transistor TR21 is the first switch element and the lower transistor TR22 is the second switch element, but this is not limited to the above. The lower transistor TR22 may be the first switch element and the upper transistor TR21 may be the second switch element. In this case, the second zero cross position B corresponds to the first zero cross position, and the MCU5 controls the on/off of the upper transistor TR21 and the lower transistor TR22 based on the second zero cross position B.

In the above-described embodiment, the MCU 5 calculates the difference ΔT between the half cycle T3/2, which is half of one period T3 from the previous second zero cross position B to the next second zero cross position B, and the period T4 from the previous second zero cross position B to the next first zero cross position A, but this is not limited to the above. The MCU 5 may also calculate the difference ΔT between the half cycle T3/2, which is half of one period T3 from the previous first zero cross position A to the next first zero cross position A, and the period T4 from the previous first zero cross position A to the next second zero cross position B.

In the above-described embodiment, the MCU 5 detects abnormal vibration when the integrated value of the difference ΔT exceeds a threshold value, but this is not limited to the above. The MCU 5 may also detect abnormal vibration when the difference ΔT exceeds a predetermined value.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

This application is based on a Japanese patent application (Patent Application No. 2022-161063) filed on October 5, 2022, the contents of which are incorporated herein by reference.

The present invention provides a drive device for a vibration compressor that can easily detect the first zero cross position, efficiently operate the vibration compressor, and reduce power consumption. The present invention, which has this effect, is useful for drive devices for vibration compressors.

4 Inverter 5 MCU (first zero cross position detection unit, inverter control unit, second zero cross position detection unit, abnormal vibration detection unit, abnormal vibration escape unit)
20 Vibration type compressor 224 Electromagnetic coil A First zero cross position B Second zero cross position DT1 First dead time (first period)
DT2 Second dead time (second period)
TR21 Upper stage transistor (first switch element)
TR22 Lower stage transistor (second switch element)

Claims

an inverter having a first switch element and a second switch element connected in series with each other, which converts direct current into alternating current by alternately turning on the first switch element and the second switch element, and supplies the converted alternating current to an electromagnetic coil of a vibration type compressor;
a first zero-cross position detection unit that detects a first zero-cross position of an induced voltage generated in the electromagnetic coil of the vibration type compressor during a first period from when the first switch element is turned off to when the second switch element is turned on;
an inverter control unit that controls an on/off period of the first switch element and the second switch element based on the first zero cross position,
The inverter control unit sets the first period to be longer than a second period from when the second switch element is turned off to when the first switch element is turned on.
2. The drive device for a vibration type compressor according to claim 1,
the inverter control unit makes the first period longer than the second period during a certain startup period immediately after power is turned on, and makes the first period equal to the second period after the startup period.
3. The vibrating compressor drive device according to claim 2,
a second zero-cross position detector that detects a second zero-cross position of an induced voltage generated in the electromagnetic coil of the vibration compressor during the second period;
An abnormal vibration detection unit that detects abnormal vibration of the vibration type compressor,
After the start-up period,
a third period is half a period between one of the first zero cross position and the second zero cross position detected in an n-th period (n is an integer) and the one of the first zero cross position and the second zero cross position detected in an n+1-th period;
a period between the one of the first zero cross position and the second zero cross position detected in the nth period and the other of the first zero cross position and the second zero cross position detected in the nth period is defined as a fourth period,
an abnormal vibration detection unit that detects the abnormal vibration of the vibrating compressor when a difference between the third period and the fourth period exceeds a predetermined value;
an abnormal vibration escape unit that escapes from the abnormal vibration state detected by the abnormal vibration detection unit.
3. The vibrating compressor drive device according to claim 2,
a second zero-cross position detector that detects a second zero-cross position of an induced voltage generated in the electromagnetic coil of the vibration compressor during the second period;
An abnormal vibration detection unit that detects abnormal vibration of the vibration type compressor,
After the start-up period,
a third period is half a period between one of the first zero cross position and the second zero cross position detected in an n-th period (n is an integer) and the one of the first zero cross position and the second zero cross position detected in an n+1-th period;
a period between the one of the first zero cross position and the second zero cross position detected in the nth period and the other of the first zero cross position and the second zero cross position detected in the nth period is defined as a fourth period,
an abnormal vibration detection unit that detects the abnormal vibration of the vibrating compressor when an integrated value obtained by integrating the difference between the third period and the fourth period for each first predetermined period exceeds a predetermined threshold value a first predetermined number of times in succession;
an abnormal vibration escape unit that escapes from the abnormal vibration state detected by the abnormal vibration detection unit.
4. The vibrating compressor drive device according to claim 3,
The abnormal vibration escape section reduces an on-duty of the first switch element and the second switch element to attenuate resonance of a spring system of the vibration compressor, thereby escaping from the abnormal vibration.
5. The drive device for a vibration type compressor according to claim 4,
After the startup period, the abnormal vibration detection unit
a third period is a half of a period between the second zero cross position detected in the nth cycle and the second zero cross position detected in the n+1th cycle;
a fourth period is defined as a period between the second zero cross position detected in the nth period and the first zero cross position detected in the nth period;
determining the difference between the third period and the fourth period;
The first predetermined period is 10 waves to 50 waves, with one wave being one cycle from the second zero cross position detected in the nth cycle to the second zero cross position detected in the n+1th cycle.
Drive device for vibrating compressor.
5. The drive device for a vibration type compressor according to claim 4,
the predetermined threshold is set so that a ratio of the difference with respect to the third period is 0.23% to 0.59%.
5. The drive device for a vibration type compressor according to claim 4,
The first predetermined number of times that the predetermined threshold value is exceeded consecutively is 3 to 10 times.
4. The vibrating compressor drive device according to claim 3,
The abnormal vibration escape section reduces the on-duty of the first switch element and the second switch element to a value between 0% and 50%.
4. The vibrating compressor drive device according to claim 3,
The abnormal vibration escape section varies an on/off period of the first switch element and the second switch element to vary a resonance frequency of a spring system of the vibrating compressor.
The drive device for a vibration type compressor according to any one of claims 3 to 10,
When the abnormal vibration is detected a second predetermined number of times during a second predetermined period after the abnormal vibration state is escaped by the abnormal vibration escape section, the inverter control section performs normal operation for a certain period thereafter.
The drive device for a vibrating compressor according to claim 11,
The drive device for a vibrating compressor, wherein the second predetermined period is one minute, and the second predetermined number of times is three times.
The drive device for a vibrating compressor according to claim 11,
The driving device for a vibration type compressor, wherein the certain period is 3 minutes.
2. The drive device for a vibration type compressor according to claim 1,
the inverter control unit sets the on-duty of the first switch element and the second switch element to a minimum on-duty at which an induced voltage can be detected immediately after a compressor operation starts, and then performs a soft start by gradually increasing the on-duty.
2. The drive device for a vibration type compressor according to claim 1,
The vibrating compressor is a driving device for a vibrating compressor that drives a refrigerator having an upward-opening lid.
an inverter having a first switch element and a second switch element connected in series with each other, which converts direct current into alternating current by alternately turning on the first switch element and the second switch element, and supplies the converted alternating current to an electromagnetic coil of a vibration type compressor;
a microcomputer that controls the on/off timing of the first switch element and the second switch element based on an input from the vibration type compressor, and outputs a drive pulse in accordance with a fluctuation in a resonance frequency of a movable part including a coil and a piston of the vibration type compressor.
17. The drive device for a vibrating compressor according to claim 16,
A driving device for a vibration type compressor, wherein an input to the vibration type compressor is an induced voltage.
17. The drive device for a vibrating compressor according to claim 16,
A driving device for a vibration type compressor, wherein an input of the vibration type compressor is an induced current.