JPH036025B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a vehicle air conditioner that is operated using a high-voltage DC overhead line as a power source, and in particular, the motor is driven by an inverter and a DC step-down device is used as the power source to generate high voltage. By converting it to low pressure and passing it between cars, it is possible to make it cheaper and smaller.

[Conventional technology]

Figures 5 to 7 are diagrams showing conventional air conditioners for vehicles; for example, Figure 7 is a
This figure shows a conventional vehicle air conditioner disclosed in Publication No. 22725.

Among these FIGS. 5 to 7, FIG. 5 is a diagram showing a combination of conventional vehicle air conditioners. In this FIG. 5, 1 is a vehicle body, and shows a case where a plurality of vehicles are connected.

In addition, 2 is a high-voltage DC overhead line, and high-voltage power supply line 3
It is connected to a DC/AC conversion type power supply device 8 (for example, a stationary three-phase AC inverter) via the AC inverter. An air conditioner 10 provided for each vehicle body 1 is connected to the output side low-voltage three-phase AC lead-in bus 9 of the DC/AC conversion type power supply device 8 .

Further, FIG. 6 is a circuit diagram showing a conventional DC/AC conversion type power supply device that supplies power to an air conditioner. In this Fig. 6, 8 indicates an example of the DC/AC conversion type power supply device shown in Fig. 5, which receives power from the high voltage DC overhead line 2 through the high voltage feeder line 3, and connects thyristor inverters 8a and 8b in parallel. It is configured to convert into DC power and output the three-phase AC power to the low-voltage three-phase AC lead-in bus 9 .

Next, the conventional air conditioner shown in FIG. 7 will be explained. This air conditioner 10 is the same as the air conditioner 10 shown in FIG. Normally open contacts 21a, 22a of contactors 21, 22, overcurrent relays 23, 24,
25 respectively, the evaporator fan motor 1
1. It is supplied to a condenser fan motor 12 and a refrigerant compressor motor 13.

In addition, between the two phases on the output side of the wiring sheath breaker 14, there is a thermostat 26 for temperature adjustment, a normally open contact 21a ₂ of the electromagnetic contactor 21, a normally closed contact 24a of the overcurrent relay 24, and an overcurrent relay 25. Normally closed contact 25
b. A series circuit of electromagnetic contactors 22 is connected.

A cooling on/off switch 1 is connected in parallel to this series circuit.
5. A series circuit of the normally closed contact 23b of the overcurrent relay 23 and the electromagnetic contactor 21 is connected.

Next, the operation will be explained. The low-voltage three-phase AC power output from the DC-AC converter power supply 8 shown in FIG. 6 is input to the air conditioner 10 through the low-voltage three-phase AC lead-in bus 9 shown in FIG.

The wiring sheath disconnector 14 in this air conditioner 10 is closed. Next, by closing the cooling on/off switch 15, the electromagnetic contactor 21 is excited. As a result, this normally open contact 21a ₁ ,
21a ₂ are closed together. This normally open contact 21a ₁
By closing, the evaporator fan motor 1
1 starts the ventilation operation.

Next, when the temperature inside the vehicle is higher than the set temperature of the temperature regulating thermostat 26, the temperature regulating thermostat 26 is closed, and as a result, the electromagnetic contactor 22 is energized. This operation closes the normally open contact 22a, starts the condenser fan motor 12 and the refrigerant compressor motor 13, and starts cooling operation.

[Problem that the invention seeks to solve]

Since the conventional air conditioner is configured as described above, a plurality of units are connected to the low-voltage three-phase AC lead-in bus 9 connected to the output side of the DC/AC conversion type power supply device 8 shown in FIGS. 5 and 6. When air conditioner 10 is connected to perform cooling operation, each air conditioner repeatedly starts and stops arbitrarily by detecting the temperature inside the vehicle, so it is necessary to start the condenser fan motor 12 and refrigerant compressor motor 13. Sometimes, an overcurrent of 5 to 6 times the rated operating current occurs. This causes a drop in the output voltage of the power supply device due to overcurrent.

Furthermore, in order to reduce this overcurrent, it is necessary to separately provide a control circuit (not shown) for sequential activation to prevent simultaneous activation of individual motors.

Furthermore, since the cooling capacity of an air conditioner was adjusted by changing the number of operating refrigerant compressor motors, the cooling capacity of each air conditioner was either 100% or 0%. Since only one of these options could be selected, there were problems such as large fluctuations in the temperature inside the car, which caused discomfort to passengers.

In addition, when a large and expensive power supply device is required and a vehicle air conditioner is mounted on a vehicle, at least three main circuit busbars are required between vehicles. In order to install a harmonization device on a vehicle and perform air conditioning operation,
There were problems such as the need for a considerable amount of installation space and high cost.

This invention was made to solve this problem, and allows each air conditioner to finely adjust its cooling capacity so that the temperature inside the vehicle is always kept constant at a preset temperature. When operating multiple air conditioners, even when starting all evaporator fan motors, condenser fan motors, and refrigerant compressor motors at the same time, or when repeatedly starting and stopping the It is possible to completely prevent overcurrent from occurring due to inrush current when
To provide a vehicle air conditioner which can reduce power supply capacity, reduce the number of main circuit busbars between vehicles, and can be made small and inexpensive.

[Means for solving problems]

The vehicle air conditioner according to the present invention includes two DC/AC converters inside the air conditioner,
The evaporator fan motor is connected to the first DC/AC converter, and the condenser fan motor and refrigerant compressor motor are connected to the second DC/AC converter. A control circuit that can automatically change the output voltage and output frequency of at least one of the first and second DC/AC converters is provided, and a conventional DC/AC converter type power supply is provided in the part that supplies driving power to the air conditioner. A DC step-down device is provided instead of the device.

[Effect]

In this invention, a high-voltage DC power source received from a DC high-voltage overhead line is stepped down to a low-voltage DC power source using a DC step-down device, and is passed between train cars using two low-voltage DC busbars. Connect the lead-in busbar to the input power supply line of the multiple vehicle air conditioners installed in each vehicle, and input low-voltage DC power to the two DC/AC converters installed inside the air conditioners. Then, each DC/AC converter operates the air conditioner by changing the output voltage and output frequency in the control circuit based on the detection of the temperature inside the vehicle.

〔Example〕

Embodiments of the vehicle air conditioner according to the present invention will be described below with reference to the drawings. FIGS. 1 to 4 are diagrams showing one embodiment of the invention, and among them,
FIG. 1 shows the overall configuration, and shows a state in which a plurality of car bodies are organized and an air conditioner is mounted on each car body. This figure 1 to 4
In the figures, the same parts as in FIGS. 5 to 7 are given the same reference numerals and explained.

First, in FIG. 1, a plurality of car bodies 1 are formed, and each car body 1 is equipped with an air conditioner 7. Power is received from the high-voltage DC overhead line 2 through the high-voltage power supply line 3 to the DC step-down device 4 .

Two low-voltage direct current busbars 5 are connected to the output side of the direct current step-down device 4. Two first DC/AC converters 6a and two second DC/AC converters 6b provided for each air conditioner 7 are connected to these two low voltage DC busbars 5, respectively.

FIGS. 2 and 3 are circuit diagrams showing an example of the DC voltage step-down device 4. FIG. In FIGS. 2 and 3, the DC voltage of the DC high-voltage overhead line 2 is applied to the DC step-down device 4 through the high-voltage power supply line 3, where it is stepped down to a predetermined DC voltage and output to the low-voltage DC lead-in bus 5. In the example shown in FIG. 2, 1500V DC of the DC high-voltage overhead line outputs a DC voltage of 600V DC to the low-voltage DC lead-in bus 5. In the DC step-down device 4 shown in FIGS. 2 and 3, L is an inductance element, and C is a capacitance element.

Next, according to FIG.
The parts of the DC/AC converter 6a and the second DC/AC converter 6b will be explained. In this FIG.
a, connected to the input side of the second DC/AC converter 6b.

Both the first DC/AC converter 6a and the second DC/AC converter 6b are mainly composed of transistors, and an evaporator fan motor 11 is connected to the output side of the first DC/AC converter 6a. A condenser fan motor 12 and a refrigerant compressor motor 13 are connected to the output side of the second DC/AC converter 6b.

The overcurrent flowing through the evaporator fan motor 11 is detected by an overcurrent detector 17.
The output of this overcurrent detector 17 is input to a control circuit 16.

Similarly, overcurrents flowing through the condenser fan motor 12 and the refrigerant compressor motor 13 are detected by overcurrent detectors 18 and 19, respectively. The outputs of these overcurrent detectors 18 and 19 are also input to the control circuit 16.

The detection output of the vehicle interior temperature detector 20 is also input to the control circuit 16 . Based on the outputs of the in-vehicle temperature detector 20 and the overcurrent detectors 17 to 19, the control circuit 16 converts the first DC/AC converter 6
a. A control signal is sent to the base of each transistor of the second DC/AC converter 6b, and these first DC/AC converter 6a and second DC/AC converter 6
The output voltage and output frequency of b are automatically changed. 15 is a cooling on/off switch.

Next, the operation of the vehicle air conditioner of the present invention configured as described above will be explained. first,
In FIGS. 2 and 3, a high voltage DC voltage received from a high voltage DC overhead line 2 through a high voltage power supply line 3 is converted into a low voltage DC voltage by a DC step-down device 4,
Electric power is supplied to the low voltage direct current bus 5.

Next, as the main circuit power supply of the air conditioner 7 shown in FIG.
The voltage is applied to the DC/AC converter 6a and the second DC/AC converter 6b. The first DC-AC converter 6a and the second DC-AC converter 6b are connected in parallel, so that the low-voltage DC voltage of the low-voltage DC bus 5 is applied simultaneously.

Next, by turning on the cooling on/off switch 15, the first DC/AC converter 6a is started.
A three-phase AC voltage is generated on its output side. This output voltage is applied to the evaporator fan motor 11, and is controlled so that the output voltage and the output frequency change simultaneously in proportion. 11 is operated.

Next, the second DC/AC converter 6b is started in the same manner as described above and generates a three-phase AC voltage on its output side. This three-phase AC voltage is controlled so that the output voltage and output frequency change proportionally and simultaneously, and the condenser fan motor 12 and refrigerant compressor motor 13 are operated simultaneously.

At this time, the second DC/AC converter 6b is controlled by the control circuit 16 so that both the voltage and frequency of the three-phase AC voltage on the output side increase as the temperature inside the vehicle increases. .

On the other hand, the control circuit 1 controls the voltage and frequency of the three-phase AC voltage on the output side of the second DC/AC converter 6b to decrease as the temperature inside the vehicle decreases.
Controlled by 6.

In the above embodiment, a case has been described in which the second DC/AC converter 6b simultaneously changes the voltage and frequency of the three-phase AC voltage on the output side depending on changes in the temperature inside the vehicle, but the first DC/AC converter 6b The device 6a may also be controlled to change in the same manner as the second DC/AC converter 6b, and the same effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As explained above, this invention connects an evaporator fan motor to a first DC/AC converter of an air conditioner, connects a condenser fan motor and a refrigerant compressor fan motor to a second DC/AC converter, The low-voltage DC voltage outputted from the DC step-down device and passed between the vehicles is supplied to the input sides of the first and second DC-AC converters, and the low-voltage DC voltage is supplied to the input sides of the first and second DC-AC converters. The three-phase AC voltage on the output side of at least one of the second DC/AC converter and the second DC/AC converter is configured such that the output voltage and frequency change simultaneously in direct proportion to the change in the temperature inside the car. You can finely adjust the cooling capacity.

Therefore, it is possible to improve the comfort inside the car and reduce the number of bus lines between cars.
In addition, a conventional power supply device is not required, and only a small-capacity DC step-down device is required, making the device small and inexpensive, resulting in an economically efficient vehicle air conditioner.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the vehicle air conditioner according to the present invention, and FIGS. 2 and 3 respectively illustrate a DC step-down device applied to the vehicle air conditioner according to the present invention. The circuit diagram, FIG. 4 is a circuit diagram mainly showing the first and second DC/AC converters in the vehicle air conditioner of the present invention, and FIG. 5 is a circuit diagram showing the entire combination of the conventional vehicle air conditioner. FIG. 6 is a circuit diagram of a DC/AC conversion type power supply device used in a conventional air conditioner, and FIG. 7 is an internal circuit diagram of the conventional air conditioner. DESCRIPTION OF SYMBOLS 1... Vehicle body, 2... High voltage DC overhead line, 3... High voltage feeder line, 4... DC step-down device, 5... Low voltage DC lead-in bus, 6a... First DC/AC converter, 6
b...Second DC/AC converter, 7...Air conditioner, 11...Evaporator fan motor, 12...
Condenser fan motor, 13... Refrigerant compressor motor, 16... Control circuit, 17-19... Overcurrent detector, 20... In-vehicle temperature detector. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A DC step-down device that receives power from a DC high-voltage overhead line to obtain a low-voltage DC voltage, an air conditioner installed in at least two or more vehicles, and a wire that runs between the vehicles from the output side of the DC step-down device to obtain the low-voltage DC voltage. two low-voltage direct current busbars that apply the voltage to each of the air conditioners, and a first direct-current alternating current provided in each of the air conditioners that converts the low-voltage direct current voltage into an alternating current voltage to drive the evaporator fan motor. conversion device,
A second DC/AC converter is provided in each of the air conditioners and converts the low voltage DC voltage into an AC voltage to drive the condenser fan motor and the refrigerant compressor motor. and a second DC-AC converter, the vehicle air conditioner includes a control means for controlling the voltage and frequency of the AC voltage on the output side of at least one of the second DC-AC converter to change simultaneously.