JP2002318048A - Refrigeration vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration vehicle for restraining noise at a low level, in the case of a cold reversing operation or a preliminarily chilling operation with compressor driving electric power being supplied from a commercial power source. SOLUTION: The refrigeration vehicle includes a generator to be driven by an engine, an input terminal to be supplied with electric power from the commercial electric source and an invertor device, for converting at least either one of an output of the generator or supplied electric power from the commercial electric source to a variable frequency alternating current, where a connection detecting means for detecting connection of the commercial electric source to the input terminal, and a frequency control means for controlling the output frequency of the invertor device, so that the number of revolutions of a compressor is limited to a lower value, when the connection of the commercial electric source is detected than that when the connection of the same is not detected are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to receive electric power from a commercial power supply in addition to a generator driven by an engine, and to convert at least one of these electric powers into a variable frequency using an inverter device. The present invention relates to a refrigerating vehicle that converts an alternating current to drive a compressor that forms a refrigeration cycle at a variable speed.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No. 2001-2001 discloses a small, light-weight refrigerating vehicle with improved energy saving and temperature controllability.
There is one disclosed in Japanese Patent No. 56170. During operation of the engine, the refrigerator described in this publication rectifies the output of a generator (AC) driven by the engine, converts the output into a three-phase AC having a variable frequency by an inverter device, and drives the compressor at a variable speed. On the other hand, when a commercial power supply is connected, the AC power of the commercial power supply is rectified and supplied to the inverter device, so that the compressor is driven at a variable speed by the commercial power supply.

In such a refrigerated vehicle, the operation of the compressor by the generator is performed during the delivery of the luggage while the engine is operating, and the operation of the compressor by the commercial power source is performed by the refrigerated vehicle such as a distribution center. This is done when you return to the yard with power supply facilities. The operation using the commercial power supply is generally used as a cold-holding operation at night or a pre-cooling operation in the early morning.

[0004]

Normally, the load of freezing or refrigeration in a refrigerator car is determined by the difference between the inside temperature and the set temperature. Therefore, in such a refrigeration vehicle, the output frequency of the inverter device is varied based on the difference between the set temperature and the internal temperature in any case, whether it is the output of the generator or the power received from the commercial power supply. By driving the compressor at a variable speed, it is possible to cope with the load. Here, when the rotation speed of the compressor is changed by the inverter device, the noise tends to increase in proportion to the rotation speed of the compressor.

[0005] On the other hand, when the insulated car returns to the yard, the temperature inside the refrigerator is often high because luggage is frequently taken in and out. Further, in the pre-cooling operation in the early morning, since the refrigeration cycle is not operated at night, the temperature in the refrigerator rises and becomes high. For this reason, in the cold-holding operation or the pre-cooling operation using the commercial power supply, an operation in which the rotation speed of the compressor is increased is performed. In this way, there is no problem if there are no houses around the distribution center that performs the cool-keeping operation or pre-cooling operation, but if there is a house, this kind of operation is performed especially at night or early morning, so noise is generated. It becomes a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can suppress noise when cooling operation or pre-cooling operation is performed by receiving compressor driving power from a commercial power supply. It aims to provide a refrigerating car.

[0007]

The invention according to claim 1 is
A generator driven by the engine, an input terminal for receiving power from the commercial power supply, and an inverter device for converting at least one of the output of the generator and the power received from the commercial power supply into a variable frequency AC, In a refrigerating vehicle that drives a compressor that forms a refrigerating cycle by an output of the inverter device at a variable speed, connection detection means for detecting that commercial power is connected to an input terminal, and connection of commercial power is detected by the connection detection means. Frequency control means for controlling the output frequency of the inverter device such that when the connection of the commercial power supply is not detected, the rotation speed of the compressor is limited to be lower than when the connection is not detected.

According to a second aspect of the present invention, there is provided a generator driven by an engine, an input terminal for receiving power from a commercial power supply, and at least one of an output of the generator and power received from the commercial power supply having a variable frequency. And a connection detecting means for detecting that a commercial power supply is connected to an input terminal in a refrigerating vehicle that drives a compressor that forms a refrigerating cycle by an output of the inverter device at a variable speed. When the connection of the commercial power supply is detected by the connection detection means, frequency control means for controlling the output frequency of the inverter device, so as to suppress the maximum rotation speed of the compressor lower than when the connection of the commercial power supply is not detected, It is characterized by having.

According to a third aspect of the present invention, in the refrigerating vehicle according to the first or second aspect, when the connection detecting means detects that the commercial power supply is connected to the input terminal, the commercial vehicle is prioritized over the generator. A commercial power supply priority means for supplying power of the power supply to the inverter device is provided.

Frequency control means for detecting a current of electric power received from a commercial power supply; and current limiting command means for outputting a current limiting command when a current detected by the current detecting means exceeds a set value. The refrigeration vehicle according to any one of claims 1 to 3, wherein the means reduces the output frequency of the inverter device according to a command from the current limiting command means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a schematic configuration diagram of a first embodiment of a refrigerator car according to the present invention. In this refrigerator car, a container 2 is connected to a cab 1. An engine 3 and a generator 4 are mounted on the outer bottom of a driver's seat (not shown) of the cab 1, and a generator 4 is mounted on an output shaft of the engine 3.
Are connected to each other. And in front of the driver ’s seat,
Operation unit 5 including at least a setting device for setting temperature
Is provided. On the other hand, a part of the front of the container 2
A freezing room and a refrigeration room are arranged side by side as a freezing / refrigerating room 6, and the rear portion is a general loading room 7.

A power supply box 8 for storing an automatic voltage regulator, a rectifier, an inverter device, a control circuit, and the like is mounted on the outer bottom of the container 2.
A load-side connection terminal 23 as an input terminal for receiving a power by connecting a commercial power supply is attached to the side of.
A compressor 16 is mounted at the front of the power supply box 8. Further, a condenser 17 constituting a refrigeration cycle is mounted on the outer front upper part of the container 2, and the refrigeration / refrigeration room 6 is provided.
The evaporator 19 is attached to the ceiling part of. Also,
A refrigerator temperature sensor 34 for detecting the temperature of the freezing / refrigeration compartment 6 is provided.

FIG. 2 is a block diagram showing the overall configuration of the control device for controlling the refrigeration cycle in the embodiment shown in FIG. 1. In FIG. 2, the same reference numerals as in FIG. Are shown. Here, it is assumed that the engine 3 is started by turning on the key switch 9. The generator 3 is connected to the engine 3. In order to keep the three-phase output voltage of the generator 4 constant even when the engine speed changes, an automatic voltage regulator 10 for controlling the field current is provided. A rectifier 12 is connected to an output terminal of the generator 4 through a contact 11 of the relay 11 (hereinafter, simply referred to as a relay 11), and a pulsating current output from the rectifier 12 is smoothed by a smoothing capacitor 13, and The supplied DC is supplied to a DC input terminal of the inverter device 14.

The inverter device 14 is, for example, an IGBT
By switching on and off these elements in a predetermined order, a three-phase AC voltage is output from an output terminal and supplied to a compressor drive motor 15 that drives a hermetic compressor 16. Is done. This compressor 1
6 forms a well-known refrigeration cycle together with the condenser 17, the expansion valve 18 and the evaporator 19.

On the other hand, in order to receive electric power from the three-phase commercial power supply 21, one end of a power cord having one end connected to the commercial power supply 21 is connected to the other end of a power supply side connection terminal 22. It can be inserted into and removed from the load-side connection terminal 23 described above. The load-side connection terminal 23 is connected via a relay contact 24 (hereinafter simply referred to as a relay 24).
It is connected to the input terminal of the rectifier 12.

Engine operation detecting means for detecting the operating state of the engine 3 based on the voltage of the connection path of the key switch 9 for switching the power receiving system and changing the inverter frequency according to the connection of the commercial power supply. 31; a commercial power supply connection detecting means 32 for detecting that a commercial power supply is connected from the load side voltage of the load side connection terminal 23; and an automatic voltage regulator 10 based on the detection results of these two detecting means. Power supply switching means 33 is provided for outputting an operation / stop command, an operation switching command for the relays 11 and 24, and a frequency limiting command for the inverter device 14.

Further, in order to drive the compressor 16 at a variable speed in accordance with the load of refrigeration or freezing, a set value of a setter 35 for setting the temperature of the freezing / refrigerating chamber 6 and a temperature of the above-mentioned internal temperature sensor 34 are set. Based on the detected temperature, a target frequency determining unit 36 that determines an output frequency for the inverter device 14 to output an AC having a frequency corresponding to the load, and a frequency limiting command output from the power supply switching unit 33, Frequency control means 37 is provided for limiting the output frequency output from the target frequency determination means 36, determining the operation frequency of the inverter device 14, and driving the same.

The operation of this embodiment configured as described above will be described below. Since the configuration and operation of the automatic voltage regulator 10 and the inverter device 14 shown in FIG. 2 and the operation of the refrigeration cycle are well known, the description thereof is omitted, and the operation of the refrigeration cycle by the output of the generator 4 is omitted. The operation of the refrigeration cycle using the commercial power supply when the commercial power supply is connected will be described.

First, when the engine 3 is started by turning on the key switch 9, the generator 4 is also driven during the operation to generate a three-phase AC voltage. In this case, even if the speed of the engine changes, the output voltage of the generator 4 is kept substantially constant by the operation of the automatic voltage regulator 10. Here, if the relay 11 is turned on, the three-phase AC voltage generated by the generator 4
And smoothed by the smoothing capacitor 13 and applied to the DC input terminal of the inverter device 14. Note that the operation state of the engine 3 is constantly detected by the engine operation detection means 31, and the power supply switching means 33 maintains the state in which the power supply switching means 33 outputs an operation command to the automatic voltage regulator 10 during operation of the engine 3.

Next, based on the difference between the inside temperature of the freezing / refrigeration room 6 detected by the inside temperature sensor 34 and the set temperature set by the setting unit 35, the target frequency determining means 36 Is determined and added to the frequency control means 37. The frequency control means 37 controls the inverter device 14 such that the three-phase AC voltage having the frequency determined by the target frequency determination means 36 is applied to the compressor drive motor 15 unless instructed by the power supply switching means 33. As a result, the compressor 16 is driven at a variable speed according to the load on the freezing / refrigeration compartment 6 using the output of the generator 4 as a power source.

Next, the power supply side connection terminal 22 for receiving electric power from the commercial power supply 21 is connected to the load side connection terminal 2 of the refrigerator vehicle.
3, the connection state is detected by the commercial power supply connection detecting means 32. The commercial power supply connection detecting means 32 detects whether or not the commercial power supply is connected by the voltage between two lines of the three-phase wiring. The power supply switching means 33 turns off the relay 11 and turns on the relay 24 at the stage of receiving the signal indicating that the commercial power supply is connected from the commercial power supply connection detecting means 32. by this,
Drive power is supplied from the commercial power supply 21 instead of the output of the generator 4. Further, in this state, the power supply switching unit 33 sets the output of the generator 4 to the
An instruction is given to the frequency control means 37 so as to reduce the rotation speed of the compressor 16, that is, to provide an operation frequency lower than the frequency determined by the target frequency determination means 36.

Specifically, the target frequency determining means 36 determines the frequency A to C (A> C) [Hz] according to the refrigeration / refrigeration load.
Is selected, the frequency control means 37 selects B to C (B <A) when a command to reduce the output frequency is applied from the power supply switching means 33.
It is converted to a frequency that changes in the range of [Hz]. Instead of changing the output frequency in the range of B to C [Hz], the output frequency can be fixed at B [Hz].

As described above, the commercial power supply 21 and the compressor 16
If the key switch 9 is turned off in the state where the driving power is supplied, the output signal of the engine operation detecting means 31 changes to the stop side, so that the power supply switching means 33 operates the automatic voltage regulator 10 To stop.

Incidentally, the commercial power supply connection detecting means 32, the power supply switching means 33, and the target frequency determining means 36 shown in FIG.
The function of the frequency control means 37 can be provided to a digital signal processing device such as a single microcomputer. FIG. 3 is a flowchart showing a processing procedure of the digital signal processing apparatus corresponding to control for fixing the output frequency to B [Hz], and the above control is realized by the following processing steps. First, in step 101, the output frequency F of the inverter device 14 is determined based on the difference between the internal temperature Ta and the set temperature Ts. At step 102, it is determined whether or not the commercial power supply is connected. If it is connected, at step 103, the relay 11 is turned off and simultaneously the relay 24 is turned on. Subsequently, in step 104, it is determined whether or not the output frequency F is higher than the frequency B having a lower value than the frequency A.
At 05, the operation frequency is determined to be B [Hz], and the inverter device 14 is operated.

On the other hand, if it is determined in step 102 that the commercial power supply is not connected, it is determined in step 106 whether or not the engine 3 is operating. The field current control of the generator 4 is started. Subsequently, in step 109, the output state of the generator 4 is checked based on the output of the voltage detecting means (not shown in FIG. 2), and if there is the output, the relay 11 is turned on in step 110 and the relay 24 is turned on. To the off state. Then, in step 111, the inverter device 14 is operated with the output frequency as it is as the operating frequency. It should be noted that, even if it is determined in step 104 that the output frequency F is lower than the frequency B, the inverter device 14 is operated at the output frequency F in step 111. If it is determined in step 106 that the engine 3 is not operating, the operation frequency is set to 0 [Hz] in step 108, and the operation of the inverter device 14 is stopped.

Thus, according to the first embodiment described with reference to FIGS. 1 to 3, the noise in the case of receiving the compressor drive power from the commercial power supply and performing the cool-keeping operation, the pre-cooling operation, etc. is suppressed. be able to.

FIG. 4 is a block diagram showing the configuration of a second embodiment of a refrigerating vehicle according to the present invention. In the drawing, the same elements as those in FIG. I do.
This is because the relays 11 and 24 shown in FIG. 2 are eliminated, the power supply switching means 33 for switching and controlling these relays is eliminated, and a rectifier 25 is newly connected after the load-side connection terminal 23, and its output terminal is connected. The configuration is different from FIG. 2 in that it is connected to the output side of the rectifier 12 and that the engine operation detection means 31 outputs an operation and stop command of the automatic voltage regulator 10. Is configured.

Hereinafter, the operation of the second embodiment shown in FIG. 4 will be described, in particular, the parts different from those in FIG. Here, the three-phase AC generated by the generator 4 is rectified by the rectifier 12, the three-phase AC of the commercial power received from the load-side connection terminal 23 is rectified by the rectifier 25, and both outputs are added to the inverter device 14. ing. Therefore, focusing only on the power supply system, power is supplied from one of the higher voltage of the rectifier 12 for rectifying the output of the generator 4 and the rectifier 25 for rectifying the power received from the commercial power supply 21. It starts, and thereafter, a forward voltage drop is caused by the rectifying element on the power supply side, so that power is supplied from the other side, and thereafter, the generator 4 corresponds to the difference in AC voltage.
In addition, electric power is shared and supplied from both the commercial power supply 21 and the commercial power supply 21.

By the way, a commercial power supply connection detecting means 32 is connected to the power supply system of the commercial power supply 21, and the frequency control means 37 controls the operating frequency to be lower than the frequency determined by the target frequency determining means 36 in accordance with the detection signal. Works to lower. On the other hand, when the engine operation detecting means 31 detects the stop of the engine 3, the operation of the automatic voltage regulator 10 is stopped.

Here, as described above, the functions of the commercial power supply connection detecting means 32, the target frequency determining means 36, and the frequency control means 37 shown in FIG. 4 can be provided to the digital signal processing device. FIG. 5 shows that the output frequency is B [H
z] is a flowchart showing a processing procedure of the digital signal processing device corresponding to control fixed to z], and realizes the above control by the following processing steps. First, step 2
At 01, the output frequency F of the inverter device 14 is determined based on the difference between the internal temperature Ta and the set temperature Ts. In step 202, it is determined whether or not the commercial power supply is connected. If the power supply is connected, in step 203, it is determined whether or not the output frequency F is higher than the frequency B having a low value. For example, in step 204, the operation frequency is determined to be B [Hz], and the inverter device 14 is operated.

On the other hand, if it is determined in step 202 that the commercial power supply is not connected, it is determined in step 205 whether or not the engine 3 is operating. 4 starts the field current control.
Subsequently, in step 208, the output state of the generator 4 is checked based on the output of the voltage detecting means (not shown in FIG. 2), and if there is an output, the output frequency F is directly changed to the operating frequency in step 209. And the inverter device 14 is operated. It should be noted that, even if it is determined in step 203 that the output frequency F is lower than the frequency B, the inverter device 14 is operated at the output frequency F in step 209. If it is determined in step 205 that the engine 3 is not operating, the operation of the inverter device 14 is stopped in step 207.

Thus, according to the second embodiment described with reference to FIGS. 4 and 5, it is also possible to reduce the noise when the compressor driving power is received from the commercial power supply and the cooling operation or the pre-cooling operation is performed. Can be.

FIG. 6 is a block diagram showing the configuration of a third embodiment of a refrigerating vehicle according to the present invention. In the drawing, the same elements as those in FIG. I do.
This embodiment includes a current transformer 41 on the input path of the rectifier 12,
Based on the output signal of the current transformer 41, the current detecting means 42
Is configured to detect the input current i. The output of the power supply switching means 33 is limited in order to limit the currents to values different from each other when the drive power is obtained from the generator 4 and when the drive power is received from the commercial power supply 21. The current set value changing means 43 for changing the current set value based on the state is compared with the current set value and the actual current detected by the current detection means 42, and when the actual current value exceeds the set value 2 is different from FIG. 2 in that a current limit command means 44 for adding a command to lower the operating frequency by a certain value to the frequency control means 37 is newly added.

The operation of the third embodiment having the above-described configuration will be described below, particularly, for portions different from those of FIG. In this embodiment, the compressor 1 is driven by the
6, the current value when driving the compressor 16 with the electric power received from the commercial power supply 21 is limited to be lower than the current value when the compressor 6 is driven, thereby lowering the rotation speed of the compressor 16 and reducing the noise. It is to try to make it. That is,
When the power supply switching means 33 receives power from the commercial power supply 21 by turning off the relay 11 and turning on the relay 24, the current set value changing means 43 sets the set value Is of the input current to Ib, When the power supply switching means 33 uses the output of the generator 4 by turning on the relay 11 and turning off the relay 24, the current set value changing means 43 sets the input current set value Is to Ia (> Ib). Set. However, Ia may be infinite.

The current limiting command means 44 compares the set value Is of the input current of the current set value changing means 43 with the current value i detected by the current detecting means 42, and when i> Is, sets the operating frequency f to a constant value. Frequency control means 37
Add to At this time, by providing the condition of Ia> Ib, it is possible to suppress noise when receiving the compressor drive power from the commercial power supply.

FIG. 7 is a flowchart showing a processing procedure when these functions are also provided in the digital signal processing device. Here, first, in step 301, the internal temperature T
a based on the difference between the set temperature Ts and the set temperature Ts.
Is determined. At step 302, it is determined whether or not the commercial power supply is connected. If it is connected, at step 303, the relay 11 is turned off and the relay 24 is turned on at the same time. Subsequently, step 304
To set the current set value Is to Ib. Subsequently, in step 305, the input current i is detected, and in step 306, it is determined whether or not the detected current i is larger than the current set value Is. Here, if it is determined that i> Is, step 307 is executed.
In step 30, the operating frequency f is reduced by a constant value Δf.
At 8, the inverter device 14 is operated at this frequency f.

On the other hand, if it is determined in step 302 that the commercial power supply is not connected, it is determined in step 309 whether or not the engine 3 is operating. 4 starts the field current control.
Subsequently, in step 312, the output state of the generator 4 is checked based on the output of the voltage detecting means (not shown in FIG. 6), and if there is the output, the relay 11 is turned on in step 313 and the relay 24 is turned on. To the off state. And
In step 314, the current set value Is is determined to be Ia, and the process proceeds to step 305. If it is determined in step 309 that the engine is not operating, the operation frequency f is set to 0 [Hz], the control of the inverter device 14 is stopped, and the compressor 16 is stopped.

Next, if it is determined in step 306 that i> Is is not satisfied, it is determined in step 315 whether or not the operating frequency f is equal to or higher than the output frequency Fs, and if it is determined that f ≧ Fs, In step 316, the output frequency Fs is determined to be the operation frequency f, and in step 308, this frequency fs
To drive the inverter device 14. If it is determined in step 315 that f ≧ Fs, that is, f <Fs
If it is determined in step 317 that the operating frequency f
Is increased by a constant value Δf, and in step 308, the inverter device 14 is operated at this frequency f. Through these processes, the control operation described with reference to the block diagram of FIG. 6 can be realized.

Thus, according to the third embodiment described with reference to FIGS. 6 and 7, the current value supplied to the inverter device 14 via the rectifier 12 is determined by receiving the compressor drive power from the commercial power supply. In this case, by suppressing the output of the generator 4 lower than in the case where the output is used, it is possible to suppress the noise when performing the cool-keeping operation or the pre-cooling operation.

FIG. 8 is a block diagram showing the configuration of a fourth embodiment of a refrigerator car according to the present invention. In the figure, the same elements as those in FIG. I do.
In this embodiment, a current transformer 41 is provided in an input path of a rectifier 25, and a current detecting means 42 detects an input current i based on an output signal of the current transformer 41. The current set value for changing the current set value based on the output state of the commercial power supply connection detecting means 32 so as to limit the current only when the driving power is received from the commercial power supply 21 without obtaining the current The change unit 43 compares the current set value with the actual current detected by the current detection unit 42, and when the actual current value exceeds the set value,
The configuration differs from that of FIG. 2 in that a current limit command unit 44 for adding a command to lower the operating frequency by a certain value to the frequency control unit 37 is newly added.

In this embodiment, the current is not limited when the compressor 16 is driven by the output of the generator 4, and the current is limited only when the driving power is received from the commercial power supply 21. Things. Although the flowchart according to this embodiment is omitted, the processing of steps 304 to 308 and the processing of steps 315 to 317 in FIG. 7 are executed.

Thus, also in the fourth embodiment described with reference to FIG. 8, the noise in the case where the compressor drive power is received from the commercial power supply to perform the cool-keeping operation or the pre-cooling operation can be suppressed.

[0043]

As is apparent from the above description, according to the present invention, the operation of the compressor with the commercial power supply connected is performed in the early morning or night in the cold preservation operation or in the pre-cooling operation.
By detecting the connection of the commercial power supply and suppressing the number of revolutions of the compressor to a low level, it is possible to prevent noise during the cool-keeping operation and during the pre-cooling operation from inconveniencing neighboring houses and the like.
In addition, although the refrigerating capacity is reduced by suppressing the number of rotations of the compressor, the refrigeration / refrigeration room can be cooled over a long period of time in the cold-holding operation or the pre-cooling operation. Driving does not cause any problems.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of a refrigerating vehicle according to the present invention.

FIG. 2 is a block diagram showing the overall configuration of a control device for controlling a refrigeration cycle in the first embodiment shown in FIG. 1;

FIG. 3 is a flowchart showing a specific processing procedure in a case where the main components constituting the first embodiment shown in FIG. 1 are provided in a digital signal processing device.

FIG. 4 shows a second embodiment of the refrigerator car according to the present invention.
FIG. 2 is a block diagram showing the overall configuration of a control device that controls the refrigeration cycle.

FIG. 5 is a flowchart showing a specific processing procedure in a case where the main elements constituting the second embodiment shown in FIG. 4 are provided in a digital signal processing device.

FIG. 6 shows a third embodiment of the refrigerator car according to the present invention.
FIG. 2 is a block diagram showing the overall configuration of a control device that controls the refrigeration cycle.

FIG. 7 is a flowchart showing a specific processing procedure in a case where the main elements constituting the third embodiment shown in FIG. 6 are provided in a digital signal processing device.

FIG. 8 shows a fourth embodiment of the refrigerating vehicle according to the present invention.
FIG. 2 is a block diagram showing the overall configuration of a control device that controls the refrigeration cycle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cab 2 Container 3 Engine 4 Generator 6 Refrigeration / refrigeration room 11,24 Relay contact 12,25 Rectifier 14 Inverter device 16 Compressor 21 Commercial power supply 23 Load side connection terminal 31 Engine operation detection means 32 Commercial power connection detection means 33 Power supply switching means 34 Internal temperature sensor 35 Setter 36 Target frequency determination means 37 Frequency control means 42 Current detection means 43 Current set value change means 44 Current limit command means

Continued on front page (72) Inventor Koji Shirai 336 Tatehara, Fuji-shi, Shizuoka Toshiba Carrier Co., Ltd. (72) Inventor Yuichi Ide 336 Tatehara, Fuji-shi, Shizuoka Toshiba Carrier Engineering Co., Ltd. (72) Invention Person Masaki Toyoda 336 Tatehara, Fuji-shi, Shizuoka Toshiba Carrier Engineering Co., Ltd. F-term (reference) 3L045 AA02 BA02 DA02 LA01 LA06 MA20 NA01

Claims (4)

[Claims] A generator driven by an engine, an input terminal for receiving electric power from a commercial power supply, and at least one of an output of the generator and electric power received from the commercial power supply are converted into an alternating current having a variable frequency. A connection detection means for detecting that a commercial power supply is connected to the input terminal, wherein the connection detection means includes: an inverter device; and a compressor that drives a compressor that forms a refrigeration cycle by an output of the inverter device at a variable speed. When the connection of the commercial power supply is detected by the means, frequency control means for controlling the output frequency of the inverter device, so as to limit the rotation speed of the compressor lower than when the connection of the commercial power supply is not detected, A refrigerating car comprising: 2. A generator driven by an engine, an input terminal for receiving electric power from a commercial power supply, and converting at least one of an output of the generator and electric power received from the commercial power supply into a variable frequency alternating current. A connection detection means for detecting that a commercial power supply is connected to the input terminal, wherein the connection detection means includes: an inverter device; and a compressor that drives a compressor that forms a refrigeration cycle by an output of the inverter device at a variable speed. When the connection of the commercial power supply is detected by the means, frequency control means for controlling the output frequency of the inverter device so as to suppress the maximum rotation speed of the compressor lower than when the connection of the commercial power supply is not detected, A refrigerating car comprising: 3. A commercial power supply priority means for supplying electric power of a commercial power supply to the inverter device prior to the generator when the connection detection means detects that a commercial power supply is connected to the input terminal. The refrigerating vehicle according to claim 1 or 2, further comprising: 4. A current detecting means for detecting a current of electric power received from a commercial power supply, and a current limiting command means for outputting a current limiting command when a current detected by the current detecting means exceeds a set value. The refrigerating vehicle according to any one of claims 1 to 3, wherein the frequency control means reduces the output frequency of the inverter device according to a command from the current limit command means.