JPH0721116Y2 - In-vehicle power generator - Google Patents

Description

[Detailed description of the device]

[Purpose of Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle power generator which is driven by an engine and supplies electric power of a constant frequency and a constant voltage to a towing refrigeration container while a tractor towing the refrigeration container is running.

[0003]

2. Description of the Related Art Generally, a frozen container is used for transporting frozen products. Recently, the quality of transportation goods transported in refrigerated containers is increasing, and even when the vehicle is traveling overland, the refrigerating machine is always operated and the trailer for transportation is equipped with a power generation facility in order to transport it while controlling it to a certain temperature. Things are increasing. As such power generation equipment, there is a system equipped with a dedicated engine generator, or the generator is directly connected to a running engine, and the output of the generator is the output of the generator because the frequency fluctuates depending on the engine speed. There is an inverter system that converts once into direct current and then into alternating current with a constant frequency.

By the way, as compared with a generator having a dedicated engine generator for a trailer, an inverter generator which is driven by a running engine of a vehicle is advantageous because it does not require such a dedicated engine. Is in the limelight.

An inverter type power generator driven by this vehicle running engine will be described with reference to the circuit diagram of FIG. That is, in FIG. 4, 1 is a running engine,
2 is an AC generator, which is the PT of the engine 1 for running the vehicle.
It is directly connected to the O-axis or connected via a gearbox (not shown) or the like. 3 is an automatic voltage regulator for controlling the output voltage of the AC generator 2 to be constant, 4 is a converter circuit for converting the output voltage of the AC generator 2 into DC, and 5 is reactive power to the compressor motor as a load. A capacitor, 6 is an inverter circuit for converting a DC voltage into an AC voltage having a constant frequency, and 7 is a capacitor 5 and an inverter circuit 6
A current detector for detecting a current flowing between the two, an inverter control circuit 8 for supplying a drive signal to the inverter circuit 6, and a refrigerating container 9, which are two types of 40 feet and 20 feet. 10 is the compressor motor of the refrigerator, 11
Detects the temperature inside the refrigerating container 9 and keeps the temperature inside this container constant with respect to the set value.
This is a temperature control device for turning on / off the compressor motor 10 at a.

By the way, as a power source for a refrigerator of a conventional refrigerating container, it is only necessary to connect a power cable so that the refrigerator can be operated by the power source in the ship during transportation and by the land power source when stored in the yard. Therefore, the generator unit cannot control the rotation speed of the compressor motor at all. Therefore, the compressor motor of the refrigerating container is directly inserted and started by this power generator.

Generally, when the induction motor is directly inserted and started,
A starting current of 5 to 6 times the rated current of the motor flows. Therefore, as the current capacity of the inverter circuit 6, a current capacity capable of flowing the starting current is required. In addition, the range of the voltage of the compressor motor used for the refrigerator is usually determined by the standard, but since the refrigerators from other countries are used for the refrigeration container, the motor voltage rating may be slightly different in some cases. is there. Furthermore, the starting current of an induction motor varies slightly depending on the manufacturer. However, in any case, it was necessary to take measures such as allowing the capacity of the power generation device to have a margin and making the voltage a double rating so that the engine could not be started.

[0008]

As described above, in the conventional power generator, the capacity of the power generator is increased in order to reliably start the refrigerators of the refrigerating containers of various manufacturers towed, and yet it is compatible with different voltages. In order to do so, it had a double voltage rating.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an in-vehicle power generator which can reliably start the voltage of the power generator without double rating even if the voltage of the refrigerator is slightly different. To do. [Device configuration]

[0010]

In order to achieve the above object, the present invention is a compressor for a refrigerating container driven and driven by a traveling engine of a tractor for towing the refrigerating container .
Constant frequency through the inverter Ressamota, the electric power generating device for supplying electric power of a constant voltage, the comp
A current detector that detects the current supplied to the lesser motor ,
A comparison circuit that compares the current value detected by this detector with the current reference value, a timer circuit that operates with the output signal of this comparison circuit, a ramp function circuit that operates with the output signal of this timer circuit, and the inverter circuit a frequency computing circuit for calculating the output frequency of the inverter by the output signal of the ramp circuit to the rated frequency setting signal, the con
When the presser motor is directly inserted and started, the compressor
The output frequency of the inverter is continuously reduced by the frequency operation circuit under the condition that the compressor does not operate.
By gradually increasing the starting torque of the motor,
It is characterized in that it is configured to start the motor .

[0011]

In the present invention, the output current flowing at the time of direct insertion start of the compressor motor of the refrigerator, which is the load of the refrigeration container, is detected, and if the current at the start continues for a certain time or longer, it is judged that the start is impossible, and the voltage is As it is,
By lowering the output frequency of the power generation device by a certain ramp function, the torque at the time of starting is increased, and the refrigerator is started by increasing the starting torque of the compressor motor. After starting the refrigerator, by returning the output frequency of the power generator to the rated frequency, the capacity of the refrigerator is not reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of the present invention shown in FIG. 1 will be described below. It should be noted that components having the same functions as those of the conventional example shown in FIG.

In FIG. 1, reference numeral 1 is a running engine, and 2 is a running engine.
Is an alternator and is a PTO of the engine 1 for running the vehicle.
It is connected directly to the shaft or via a gearbox (not shown) or the like. 3 is an automatic voltage regulator for controlling the output voltage of the AC generator 2 to be constant, 4 is a converter circuit for converting the output voltage of the AC generator 2 into DC, and 5 is reactive power to the compressor motor as a load. A capacitor,
6 is an inverter circuit that converts a DC voltage into an AC voltage having a constant frequency, 7 is a current detector that detects a current flowing between the capacitor 5 and the inverter circuit 6, and 8 is an inverter control that supplies a drive signal to the inverter circuit 6. Circuit, 9
Is a refrigeration container, and there are two types, 40 feet and 20 feet. 10 is a compressor motor of the refrigerator, 11 is a temperature control for detecting the temperature in the refrigerating container 9 and turning on / off the compressor motor 10 by the contactor 11a so that the temperature in the container is always constant with respect to the set value. It is a device. 12 is a current detector that detects the starting current of the refrigerator, 13
Is a current reference value for determining the starting current, 14 is a comparison circuit for comparing the starting current reference value 13 and the current detector 12, 15
Is a timer circuit that operates according to the output of the comparison circuit 14, 16
Is a ramp function circuit, 17 is a frequency setter for setting the rated frequency of the power generator, and 18 is a frequency calculation circuit for adding the set value of the frequency setter 17 and the output of the ramp function circuit 16.

The operation of the on-vehicle power generator of the present invention thus constructed will be described with reference to the time charts of FIGS.

FIG. 2 shows an example when the compressor motor is started without any particular problem. That is, since the starting current of 5 to 6 times the rated current flows and the starting of the compressor motor is completed within the normal starting time, the comparison circuit 14 becomes 0 level, and the timer circuit 15 does not output. Therefore, the on-vehicle power generator always outputs a constant frequency.

FIG. 3 shows an example in which the compressor motor cannot be started at the rated frequency. The compressor motor is connected to the vehicle-mounted power generator and a starting current flows, but the compressor motor cannot be started and the rotation speed does not increase. The comparison circuit 14 outputs that the starting current is flowing, and when the starting time is longer than the normal starting time, the output of the timer circuit 15 becomes 1 level. When the output of the timer circuit 15 becomes 1 level, the ramp function circuit 16 outputs to decrease the output frequency at a certain fixed time. Although the rated frequency of the on-vehicle power generator is 60 Hz, the lower limit value of the frequency by the ramp function circuit 16 may be changed as necessary, but normally the limit is 50 Hz. The starting torque of an induction motor is generally expressed by the following equation.

T _ST = k · r ₂ · V ² / ω · Z (1) T _ST : Induction motor starting torque k: Proportional constant r ₂ : Secondary resistance V: Applied voltage ω: Angular frequency Z: Primary , Secondary synthetic impedance That is, if the voltage applied to the induction motor is constant, the starting torque changes depending on the applied frequency, and if the frequency is lowered, the starting torque increases.

Therefore, since the starting torque increases as the output frequency is lowered, the compressor motor starts to start and the number of revolutions increases, and the compressor motor is operated at the number of revolutions corresponding to the output frequency. When the compressor motor completes starting, the starting current decreases and the outputs of the comparison circuit 14 and the timer circuit 15 become 0 level. As a result, the output frequency returns to the rated frequency by the ramp function for a certain fixed time period. Therefore, the rotation speed of the compressor motor is also operated at the rated rotation speed.

[0019]

As described above, according to the on-vehicle power generator of the present invention, the starting torque of the compressor motor of the refrigerator of the refrigerating container can be increased, so that the compressor which should not occur should not occur. It is possible to eliminate the inability to start due to a slight difference in voltage and capacity. Therefore, there is no need to provide an on-vehicle power generator having a capacity larger than necessary just to increase the torque at the time of starting, which is a very excellent practical effect.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention.

FIG. 2 is a time chart for explaining the operation of the vehicle-mounted power generator of the present invention (when the compressor motor is started).

FIG. 3 is a time chart for explaining the operation of the in-vehicle power generator of the present invention (when the compressor motor cannot be started).

FIG. 4 is a circuit configuration diagram of a conventional vehicle-mounted power generator.

[Explanation of symbols]

1 ... Running engine, 2 ... Alternator, 3 ... Automatic voltage regulator, 4 ... Converter circuit, 5 ... Capacitor, 6 ... Inverter circuit, 7 ... Current detector, 8 ... Inverter control circuit, 9 ... Refrigerating container, 10 ... Compressor motor of refrigerator, 11 ... Temperature control device, 12 ... Current detector, 13 ... Current reference value, 14 ... Comparison circuit, 15 ... Timer circuit, 16 ... Ramp function circuit, 17 ... Frequency setting device, 18 ... Frequency calculation circuit.

Claims (1)

[Scope of utility model registration request] 1. A compressor for a refrigerating container, which is driven and towed by a running engine of a tractor for towing the refrigerating container .
Constant frequency through the inverter Ressamota, the electric power generating device for supplying electric power of a constant voltage, the comp
A current detector that detects the current supplied to the lesser motor ,
A comparison circuit that compares the current value detected by this detector with the current reference value, a timer circuit that operates with the output signal of this comparison circuit, a ramp function circuit that operates with the output signal of this timer circuit, and the inverter circuit a frequency computing circuit for calculating the output frequency of the inverter by the output signal of the ramp circuit to the rated frequency setting signal, the con
When the presser motor is directly inserted and started, the compressor
The output frequency of the inverter is continuously reduced by the frequency operation circuit under the condition that the compressor does not operate.
By gradually increasing the starting torque of the motor,
An in-vehicle power generator, which is configured to start a motor .