Driving device for vibration type compressor

Abstract

To provide a vibration type compressor capable of easily detecting a first zero-cross position to efficiently operate the vibration type compressor, thereby capable of reducing power consumption.SOLUTION: An MCU 5 detects a first zero-cross position A of an induced voltage generated in an electromagnetic coil 224 of a vibration type compressor 20 in a first dead time DT1 from when an upper stage transistor TR21 turns off until a lower stage transistor TR22 turns on. The MCU 5 controls an on / off period of the upper stage transistor TR21 and the lower stage transistor TR22 on the basis of the first zero-cross position A. Besides, the MCU 5 makes the first dead time DT1 longer than a second dead time DT2 at a time of startup.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a drive device for a vibrating compressor. [Background technology]

[0002] As a drive device for the above-mentioned vibrating compressor, for example, the one described in Patent Document 1 is known. The drive device for the vibrating 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 vibrating 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.

[0003] It is also possible to control the upper and lower switches based on the zero-cross position where the induced voltage input to the vibrating compressor becomes 0 V other than the second peak. However, there is a problem that the amplitude of the vibrating compressor is small at the time of startup, making it difficult to detect the zero-cross position, and the vibrating compressor cannot be operated efficiently.

[0004] Furthermore, the driving device for the vibrating compressor in Patent Document 1 has a problem in that the frequency tracking circuit needs to be changed depending on the type of the vibrating compressor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-178149 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a drive device for a vibration type compressor that can easily detect a first zero cross position, efficiently operate a vibration type compressor, and reduce power consumption.

[0007] The present invention also provides a drive device for a vibrating compressor that can perform frequency tracking regardless of the type of vibrating compressor. [Means for solving the problem]

[0008] 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. It is a driving device for a vibrating compressor. [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. It is a driving device for a vibrating compressor. [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 type 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; It is a driving device for a vibrating compressor. [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 type 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 vibration type 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; It is a driving device for a vibrating compressor. [5] In the drive device of the vibration type compressor according to [3], The abnormal vibration escape unit reduces the 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. It is a driving device for a vibrating compressor. [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 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. 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 the ratio of the difference to the third period is 0.23% to 0.59%. It is a driving device for a vibrating compressor. [8] In the drive device of the vibration type compressor according to [4], The first predetermined number of times that the predetermined threshold is exceeded consecutively is 3 to 10 times. It is a driving device for a vibrating compressor. [9] In the drive device of the vibration type compressor according to [3], The abnormal vibration escape unit reduces the on-duty of the first switch element and the second switch element to between 0% and 50%. It is a driving device for a vibrating compressor.

[10] In the drive device of the vibration type compressor according to [3], The abnormal vibration escape unit 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. It is a driving device for a vibrating compressor.

[11] The drive device for a vibration-type compressor according to any one of [3] to

[10] , When 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. It is a driving device for a vibrating compressor.

[12]

[11] The drive device for the vibration-type compressor according to the present invention, The second predetermined period is one minute, and the second predetermined number of times is three. It is a driving device for a vibrating compressor.

[13]

[11] In the drive device of the vibration type compressor according to The period is 3 minutes. It is a driving device for a vibrating compressor.

[14] [In the drive device of the vibration type compressor described in 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. It is a driving device for a vibrating compressor.

[15] [In the drive device of the vibration type compressor described in 1, The vibrating compressor drives a refrigerator having a top-opening lid. It is a driving device for a vibrating compressor.

[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; 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 change in a resonance frequency of a movable part including a coil and a piston of the vibration type compressor. It is a driving device for a vibrating compressor.

[17]

[16] The drive device for the vibrating compressor according to the present invention, The input of the vibration type compressor is an induced voltage. It is a driving device for a vibrating compressor.

[18]

[16] The drive device for the vibrating compressor according to the present invention, The input of the vibration type compressor is an induced current. It is a driving device for a vibrating compressor.

[0009] According to the driving 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 the induced voltage having the 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 above configuration [2], 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 vibrating compressor driving device 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 driving device for a vibrating compressor having the above configurations [6] to [8], 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 vibrations. According to the driving 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 of 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. Effect of the Invention

[0010] According to the present invention, it is possible to provide a vibrating compressor that can easily detect the first zero cross position, can efficiently operate the vibrating compressor, and can reduce power consumption.

[0011] The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading the following description of the embodiment of the present invention (hereinafter, referred to as "embodiment") with reference to the accompanying drawings. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a circuit diagram showing an embodiment of a drive device for a vibration type compressor according to the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view of the vibrating compressor shown in FIG. [Diagram 3]FIG. 3 is a time chart of the inverter output voltage, the piston position, the timer count value, the on / off state 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. [Figure 4] FIG. 4 is a flowchart showing a processing procedure of the main processing executed by the MCU shown in FIG. [Diagram 5] FIG. 5 is a flowchart of the procedure of the output period processing executed by the MCU shown in FIG. [Figure 6] FIG. 6 is a flowchart of the interrupt process executed by the MCU shown in FIG. [Figure 7] FIG. 7 is a flowchart of a timer process executed by the MCU shown in FIG. [Figure 8] FIG. 8 is a time chart of the on / off of the power supply and the compressor current of the vibration-type compressor shown in FIG. [Figure 9] FIG. 9 is a time chart of 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. [Figure 10] FIG. 10 is a time chart of the output voltage of the inverter for explaining the abnormal vibration detection process. [Figure 11] FIG. 11 is a flowchart illustrating a procedure of the abnormal vibration detection process executed by the MCU shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0014] Fig. 1 is a circuit diagram showing one embodiment of a drive device for a vibrating compressor of the present invention. The vibrating compressor 20 is for driving a refrigerator mounted on, for example, an automobile or a refrigerator in which the container itself serves as a refrigerator, and operates on a low AC voltage. In this embodiment, the vibrating compressor 20 drives a refrigerator having an upward-opening lid.

[0015] 1 (hereinafter simply referred to as "drive device") drives the vibration compressor 20 using a battery 30 such as that installed in an automobile when a commercial AC power source 40 is not connected to a 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.

[0016] First, before describing the configuration of the drive device 1, the vibration type compressor 20 will be described with reference to Fig. 2. The vibration type 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 on the top and bottom. 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 resonance springs 226, 226 that urge the piston 225 from above and below. The vibration type compressor 20 supplies AC power to an electromagnetic coil 224 to vibrate a piston 225 connected to the electromagnetic coil 224, causing a low-pressure refrigerant to flow into the sealed container 21 and discharging a compressed high-pressure refrigerant.

[0017] 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.

[0018] The AC / DC converter 2 converts AC power from a commercial AC power source 40 into a desired DC power source. The DC / DC converter 3 boosts a DC battery voltage VB supplied from a battery 30 and converts it into a desired DC power source. The DC / DC converter 3 includes Zener diodes DZ1 and DZ2 for surge protection, a filter circuit 31 for removing high frequency components from the battery voltage VB, a reverse current prevention circuit 32, a coil L1, a transistor TR1, a diode D2, capacitors C11 and C12, and capacitors C21 and C22.

[0019] One end of the coil L1 is connected to the positive electrode of the battery 30 via a filter circuit 31, and a battery voltage VB from which high-frequency components have been removed is supplied. 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.

[0020] According to 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.

[0021] The diode D1 is connected between the AC / DC converter 2 and the inverter 4. To explain in detail, the anode of the 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 the AC / DC converter 2 is supplied to the inverter 4 via the diode D1.

[0022] The diode D2 is connected between the DC / DC converter 3 and the inverter 4. To explain in detail, the anode of the 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 the DC / DC converter 3 is supplied to the inverter 4 via the diode D2.

[0023] The inverter 4 converts the DC power converted by the AC / DC converter 2 or the DC / DC converter 3 into AC power and supplies it to the electromagnetic coil 224 of the vibration type compressor 20. The inverter 4 includes an upper-stage transistor TR21 as a first switch element and a lower-stage transistor TR22 as a second switch element connected in series between the cathodes of diodes D1, D2 and the ground, capacitors C31, C32 for cutting DC components, and a smoothing coil L2.

[0024] 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 a DC / DC converter IC10 (described later) and are alternately turned on and off.

[0025] One end of each of the capacitors C31 and C32 is connected to the source of the upper-stage transistor TR21 and the drain of the lower-stage 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.

[0026] Next, the on / off of the upper transistor TR21 and the lower transistor TR22 during duty up and steady state described below will be described with reference to Fig. 3. As shown in the figure, the upper transistor TR21 and the lower transistor TR22 are alternately turned on, and 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 turned off are provided between the on period of the upper transistor TR21 and the on period of the lower transistor TR22.

[0027] When the upper transistor TR21 is turned on and the lower transistor TR22 is turned 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 to move 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.

[0028] 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, and a positive induced voltage is generated 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 a neutral position on the bottom dead center side due to the biasing force of the resonance spring 226, and a negative induced voltage is generated in the output voltage VOUT.

[0029] 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 voltages 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 to move the piston 225 to the bottom dead center, and the piston 225 moves past the neutral position toward the bottom dead center.

[0030] 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 0 V. 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 resonance spring 226, which generates a positive induced voltage in the output voltage VOUT.

[0031] 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 become 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 obtained by AD conversion to the MCU 5. The MCU 5 controls the duty by varying the duty so that the power supplied to the vibration type compressor 20 is constant based on the voltage of the input voltage detection unit 9.

[0032] 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 a 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 a 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.

[0033] 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 value obtained by AD conversion 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, to which the cathodes of the diodes D3 and D4 are connected, converts the output voltage VOUT2 and the battery voltage VB into a desired DC voltage (for example, 11 V) and outputs it to the fan 13.

[0034] Next, the operation of the drive device 1 having the above-mentioned configuration 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).

[0035] In the AC priority process, the MCU 5 judges 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. When the AD value acquired in S3 is higher than the battery voltage VB, the MCU 5 judges that the commercial AC power supply 40 is connected to the plug 14, and stops outputting an enabling signal to the DC / DC converter IC10. The DC / DC converter IC10 stops controlling the transistor TR1 while the enabling signal is stopped, and does not perform a 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 vibration type compressor 20 is driven by the commercial AC power supply 40.

[0036] On the other hand, when the AD value captured by 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 IC10. The DC / DC converter IC10 controls the transistor TR1 and performs a boost operation while the enable signal is being output. 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 vibration type compressor 20 is driven by the battery 30.

[0037] Next, 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.

[0038] First, the output period process 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.

[0039] Next, the MCU 5 determines whether the first zero cross position A is greater than a reference (S72). The 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 the top dead center, and is the position at which the induced voltage generated in the electromagnetic coil 224 becomes 0V during a first dead time DT1 from when the upper transistor TR21 is turned off until the lower transistor TR22 is turned on. To explain in more detail, the MCU 5 repeatedly performs a timer process that counts up from 0 to 1023. The first zero cross position A is the count value by the timer process when the induced voltage reaches 0V.

[0040] The time for counting from 0 to 1023 is approximately equal to the resonance period of the resonance spring 226. However, since the resonance period of the movable part including the electromagnetic coil 224 and the piston 225 changes due to the temperature of the resonance spring 226, load fluctuation, etc., in this embodiment, the MCU 5 finely adjusts 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 movable part including the electromagnetic coil 224 and the piston 225 vibrates at the resonance frequency of the resonance spring 226.

[0041] Returning to the flow chart 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, lengthens the next output period slightly (S73), and then proceeds 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.

[0042] 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.

[0043] A specific example of the output period set by the above output period process 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 process is equal to the reference, so the MCU5 does not change the next output period T12. The first zero cross position A detected in the next timer process is "511", which is smaller than the reference, so the MCU5 slightly shortens the next output period T13. Furthermore, the first zero cross position A detected in the next timer process is "513", which is larger than the reference, so the MCU5 slightly lengthens the next output period T14.

[0044] Moreover, the MCU5 executes a first interrupt process shown in Fig. 6 to detect the first zero cross position A. As shown in Fig. 3, the MCU5 sets the first dead time DT1 as the first detection range. The MCU5 determines that a zero cross has occurred at the timing 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 MCU5 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.

[0045] The MCU5 also functions as an inverter control unit, and executes the timer process shown in Fig. 7 for controlling 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 executes a duty output process that captures the on-duty set in the output cycle process (S10). Next, the MCU5 executes an output process (cycle) that captures the output cycle set in the output cycle process, and outputs the captured on-duty and drive pulses of the output cycle to the upper transistor TR21 and the lower transistor TR22 (S11).

[0046] As shown in Fig. 8, the MCU 5 executes a soft start immediately after power-on. As shown in the figure, when the MCU 5 executes S71 in Fig. 5 at startup, for example, 2 seconds after power-on, it sets the on-duty to a predetermined minimum duty without setting the on-duty according to temperature. In this embodiment, the minimum duty is set to 5% to ensure a certain level of induced voltage (1V or higher).

[0047] Next, when the MCU 5 executes S71 in Fig. 5 during duty-up for, for example, 3 seconds after startup, the MCU 5 gradually increases the on-duty. After that, when the MCU 5 executes S17 in Fig. 5 during steady state after the duty-up, the MCU 5 sets the on-duty according to the temperature as described above.

[0048] Furthermore, 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 executing S11 in Fig. 7 at startup, the MCU 5 sets the first dead time DT1 to be longer than the second dead time DT2 from when the lower-stage transistor TR22 is turned off to when the upper-stage transistor TR21 is turned on, as shown in Fig. 9.

[0049] Thereafter, when executing S11 in FIG. 7 during duty-up and steady state, the MCU 5 makes the first dead time DT1 and the second dead time DT2 equal to each other as shown in FIG.

[0050] As described above, by making the first dead time DT1 > the second dead time DT2 at startup, even at startup when the amplitude of the piston 225 is small, the first detection range can be made longer and the minute first zero cross position A can be easily detected. As a result, the vibration compressor 20 can be operated efficiently and power consumption can be reduced.

[0051] Next, the details of the abnormal vibration detection process described above will be described with reference to Fig. 10 and Fig. 11. The MCU 5 performs the abnormal vibration detection process during normal operation, but does not perform it during duty-up or startup. The resonance spring 226 and the vibration-proof spring 23 of the vibration compressor 20 abnormally vibrate due to the road surface conditions of the vehicle, the suspension of the vehicle, the vehicle installation conditions, etc., and the compressor body 22 hits the sealed container 21, generating an abnormal noise (a 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 that the abnormal vibration detection process can detect such abnormal vibration.

[0052] To perform the abnormal vibration detection process, 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 process when the induced voltage reaches 0V.

[0053] 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.

[0054] 10, in the abnormal vibration detection process, 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).

[0055] Next, the MCU5 accumulates the calculated difference ΔT (S802). When the difference ΔT for 25 waves (=first predetermined period), where one cycle is one wave 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 MCU5 judges whether the accumulated value exceeds a threshold value (S804). The first predetermined period is a period of one wave, where one cycle is one wave 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 MCU5 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.

[0056] 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 (=first predetermined number of times) in succession (S805). The first predetermined number of times is the number of times that the integrated value exceeds the threshold consecutively, and is set to six times in this embodiment. If the integrated value exceeds the threshold six times in succession (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 if a threshold is set such that the ratio of the difference ΔT to the half cycle T3 / 2 is 0.23% to 0.59%, it is possible to suppress erroneous detection of abnormal vibration during normal operation. That is, the threshold may be set to 25×0.25%×T3 / 2 to 25×0.59%×T3 / 2.

[0057] 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.

[0058] Furthermore, when abnormal vibration is detected, if a three-minute timer that counts three minutes (=a fixed period) described below is not in the middle of 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-stage transistor TR21 and the lower-stage transistor TR22 to 0% to stop the drive of the vibration type compressor 20. Furthermore, the MCU 5 may, for example, vary the output cycle of the upper-stage transistor TR21 and the lower-stage transistor TR22.

[0059] Next, the MCU 5 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 MCU 5 starts a three-minute timer (S810) and then ends the abnormal vibration detection process. On the other hand, if the three-minute timer is counting even when abnormal vibration is detected (Y in S807), the MCU 5 immediately ends the abnormal vibration detection process without performing the escape 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 certain 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.

[0060] According to the above-mentioned embodiment, the MCU5 integrates the difference ΔT of 25 waves, detects abnormal vibration when the integrated value exceeds the threshold value six times in a row, and performs an escape process from the abnormal vibration when the abnormal vibration is detected. This makes it possible to detect abnormal vibration and escape from the abnormal vibration without installing a vibration sensor or the like.

[0061] According to the above-described embodiment, the MCU 5 reduces the duty of the upper transistor TR21 and the lower transistor TR22 in the escape process, which attenuates the resonance of the resonance spring 226 and the vibration-proof spring 23 of the vibration type compressor 20, and allows the compressor 20 to escape from the abnormal vibration.

[0062] According to the embodiment described above, in the escape process, the MCU 5 varies the output periods of the upper stage transistor TR21 and the lower stage transistor TR22, thereby making it possible to escape from the abnormal vibration.

[0063] According to the above-mentioned embodiment, if abnormal vibration is detected three times within one minute after performing the process of escaping from abnormal vibration, the MCU 5 does not perform the process of escaping from abnormal vibration for three minutes. As a result, cooling is not stopped for three minutes after the process of escaping from abnormal vibration is performed once and cooling is stopped, so that excessive stopping of the refrigerator can be prevented and cooling performance can be maintained.

[0064] According to the above-described embodiment, the MCU 5 minimizes the on-off duty of the upper transistor TR21 and the lower transistor TR22 immediately after power-on, and then performs a soft start by gradually increasing the on-duty. This allows the vibration compressor 20 to be stably started after power-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 more cost-effective.

[0065] According to the embodiment described above, the drive unit 1 drives a refrigerator having an upward-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 type compressor 20, the cooling performance can be maintained because cold air is unlikely to leak.

[0066] According to the above-described embodiment, the MCU 5 controls the on / off timing of the upper transistor TR21 and the lower transistor TR22 to vibrate the vibration type compressor 20 in accordance with the resonance frequency. This makes it possible to change software (e.g., threshold value, etc.) depending on the type of the vibration type compressor 20 (e.g., type of the resonance spring 226), and frequency tracking becomes possible regardless of the type of the vibration type compressor 20.

[0067] The present invention is not limited to the above-described embodiment, and can be modified, improved, etc. as appropriate. The material, shape, size, 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 a top-opening lid, and can also be applied to a refrigerator with a front-opening door.

[0068] According to the above-mentioned embodiment, the first predetermined period for detecting abnormal vibration is set to 25 waves, but is not limited to this. It has been experimentally confirmed that abnormal vibration can be detected if the first predetermined period is set to between 10 waves and 50 waves.

[0069] According to the above-described embodiment, the first predetermined number of times for detecting abnormal vibration is set to 6 times, but is not limited to this. It has been experimentally confirmed that abnormal vibration can be detected if the first predetermined number of times is set to between 3 times and 10 times.

[0070] In addition, according to 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 abnormal vibration escape process, but this is not limited to this. It has been experimentally confirmed that it is possible to escape from the abnormal vibration by reducing the on-duty between 0% and 50%.

[0071] According to 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 vibrating compressor 20, but the present invention is not limited to this. The MCU 5 may control the on / off of the upper transistor TR21 and the lower transistor TR22 based on the current input to the vibrating 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.

[0072] According to 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 thereto. 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 MCU 5 controls the on / off of the upper transistor TR21 and the lower transistor TR22 based on the second zero cross position B.

[0073] According to the embodiment described above, 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 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.

[0074] According to the embodiment described above, the MCU 5 detects abnormal vibration when the integral value of the difference ΔT exceeds a threshold value, but this is not limited thereto. The MCU 5 may detect abnormal vibration when the difference ΔT exceeds a predetermined value. [Explanation of symbols]

[0075] 4 Inverter 5 MCU (first zero-cross position detector, inverter controller, second zero-cross position detector, abnormal vibration detector, abnormal vibration escape unit) 20 Vibration compressor 224 Electromagnetic Coil A 1st zero cross position B Second zero cross position DT1 First dead time (first period) DT2 Second dead time (second period) TR21 Upper transistor (first switch element) TR22 Lower transistor (second switch element)

Claims

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 detector 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. Vibration compressor drive unit.

2. 2. The driving 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-on, and makes the first period equal to the second period after the startup period. Vibration compressor drive unit.

3. 3. The driving device for a vibration-type compressor 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 of 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 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. Vibration compressor drive unit.

4. 3. The driving device for a vibration-type compressor 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 of 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 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. Vibration compressor drive unit.

5. 4. The driving device for a vibration-type compressor according to claim 3, The abnormal vibration escape unit reduces on-duties 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.

6. 5. The driving device for a vibration-type compressor according to claim 4, After the startup period, the abnormal vibration detection unit a third period that is half of a period between the second zero cross position detected in the nth period and the second zero cross position detected in the n+1th period; 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 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; Vibration compressor drive unit.

7. 5. The driving device for a vibration-type compressor according to claim 4, The predetermined threshold is set so that the ratio of the difference to the third period is 0.23% to 0.59%. Vibration compressor drive unit.

8. 5. The driving 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. Vibration compressor drive unit.

9. 4. The driving device for a vibration-type compressor according to claim 3, The abnormal vibration escape unit reduces the on-duty of the first switch element and the second switch element to between 0% and 50%. Vibration compressor drive unit.

10. 4. The driving device for a vibration-type compressor according to claim 3, The abnormal vibration escape unit varies the on / off cycles of the first switch element and the second switch element to vary the resonance frequency of a spring system of the vibration compressor. Vibration compressor drive unit.

11. The driving device for a vibration 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 unit, the inverter control unit performs normal operation for a certain period thereafter. Vibration compressor drive unit.

12. The driving device for a vibrating compressor according to claim 11, The second predetermined period is one minute, and the second predetermined number of times is three. Vibration compressor drive unit.

13. The driving device for a vibrating compressor according to claim 11, The fixed period is 3 minutes. Vibration compressor drive unit.

14. 2. The driving 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 the compressor starts operating, and then performs a soft start by gradually increasing the on-duty. Vibration compressor drive unit.

15. 2. The driving device for a vibration-type compressor according to claim 1, The vibration type compressor drives a refrigerator having an upward opening lid. Vibration compressor drive unit.

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