JPH0739266B2 - Control method for vehicle air conditioner - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control method for a vehicle air conditioner (hereinafter abbreviated as an air conditioner).

[Conventional technology]

FIG. 2 shows a power supply system diagram of an air conditioner. In the figure, 1 is an overhead line or an electric line such as a third rail, 2 is a pantograph provided on a vehicle (not shown), and 3 is a switch 4. DC / DC converters, 5a, 5b, which are connected to the pantograph 2 and output a constant DC voltage, for example 600V, by compensating for fluctuations of the DC voltage, for example 1500V ± 20%, input from the train line 1
Variable voltage / variable frequency inverter device (hereinafter referred to as VVVF inverter device) that converts the DC voltage output from the DC / DC converter 3 into an AC voltage, and 6a and 6b are air conditioners that receive power from the VVVF inverter devices 5a and 5b. 7a, 7b air conditioning compressor motor.

As shown in FIG. 3, the DC / DC converter 3 includes an input filter capacitor 8, a chopper switching element 9, a chopper flywheel diode 10, a chopper output DC reactor 11, and a chopper output filter capacitor 12. Configured and input DC reactor 1
3. The power is received from the power supply side through the DC high speed circuit breaker 14.

Next, the operation will be described. Pantograph 2 is train line 1
The received voltage from the DC / DC converter 3 is input to the DC / DC converter 3 via the switch 4. The DC / DC converter 3 compensates for fluctuations in the received voltage and outputs a constant DC voltage.

The VVVF inverter devices 5a and 5b convert the constant DC voltage output from the DC / DC converter 3 into a three-phase AC voltage and output the three-phase AC voltage to drive the air conditioning compressor motors 6a and 6b.

In this case, the DC / DC converter 3 sets the conduction angle α of the chopper switching element 9 to 50% when the train line voltage is the rated voltage as shown in FIG. If the voltage fluctuates more than the rated voltage, Fig. 4b
As shown in, the flow angle α is reduced (30% in the example shown),
The chopper output DC reactor 11 and the chopper output filter capacitor 12 increase the amount of energy stored (hatched portion in FIG. 4).

Further, when the train line voltage fluctuates below the rated voltage, the conduction angle α is increased as shown in FIG.
90%) to reduce the discharge of energy stored in the chopper output DC reactor 11 and the chopper output filter capacitor 12. As a result, the DC / DC converter 3 always outputs a constant DC voltage that compensates for fluctuations in the electric line voltage.

[Problems to be Solved by the Invention]

Since the power supply system diagram of the conventional air conditioner is configured as above, the DC / DC converter is a large-sized and large-capacity DC reactor for chopper output, a chopper output filter capacitor for storing energy for voltage compensation. However, there is a problem in that the size of the entire apparatus becomes large.

The present invention has been made in order to solve the above-mentioned problems, and aims to reduce the size and weight of the device as well as the operation,
An object of the present invention is to obtain a control method for a vehicle air conditioner that does not cause any trouble.

[Means for Solving the Problems]

A control method for a vehicle air conditioner according to the present invention is a DC / DC converter that compensates for fluctuations when a train line voltage fluctuates above a rated voltage and does not compensate when the train line voltage fluctuates below a rated voltage. The device and a variable voltage / variable frequency inverter device for varying the frequency so as to keep the torque of the compressor motor constant when the output voltage of the DC / DC converter device decreases.

[Action]

The DC / DC converter device according to the present invention performs voltage compensation only when the train line voltage as the input voltage rises or exceeds the rated voltage, and thereby a chopper output DC reactor used for energy storage and a chopper output filter. Capacitors such as small size and small capacity are enough,
The entire device can be miniaturized. Also, if the output voltage of the DC / DC converter device drops because compensation is not performed regardless of the drop in the input voltage, change the frequency of the variable voltage / variable frequency inverter device so that the drive torque of the compressor motor is not changed. By doing so, the air conditioner does not cause any malfunction in operation.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. First
The figure is a timing chart showing the states of the input voltage and the output voltage for explaining the control method of the present invention. A waveform diagram of the output voltage, (c) is a waveform diagram of the output voltage and the frequency of the VVVF inverter devices 5a and 5b.

Next, the operation will be described. As shown in FIG. 1, when the input voltage changes rapidly from DC1500V to DC1650V at time T1, voltage compensation is performed in the DC / DC converter 3 and the D
The output voltage of the C / DC converter is maintained at a constant DC voltage of 600 VDC. Therefore, VVVF that inputs this constant DC voltage
The output voltage and frequency of the inverter devices 5a, 5b are also 440V, 60
It is kept constant at Hz.

Then, the input voltage drops from DC1650V to DC1500V at T2, and gradually decreases from DC1500V to DC1200V at T3.
In this case, since the DC / DC converter 3 does not perform voltage compensation, its output voltage also gradually decreases to 480V at time T3.

Therefore, the output voltage of the VVVF inverter device 5a, 5b is also 352V.
Compressor motor 6a, 6b with this output voltage
When is driven, the performance of the air conditioners 7a and 7b deteriorates.

Therefore, the torque T of the compressor motors 6a and 6b, that is, (However, k is a constant, f is a frequency, and V is an input voltage.) By changing the frequency f from 60Hz to 48Hz, the torque T can be kept constant regardless of the decrease of the input voltage. Therefore, it is possible to prevent the performance of the air conditioners 7a and 7b from being degraded. This frequency change is due to the VVVF inverter device
This is done by 5a and 5b itself.

〔The invention's effect〕

As described above, according to the present invention, the DC / DC converter device is configured to perform voltage compensation only when the input voltage rises above the rated voltage, so that the reactor and capacitor for energy storage are small and small. The capacity is sufficient, and the size and weight of the entire device can be reduced. Also, VVVF
When the input voltage drops, the inverter device changes the frequency so that the torque of the compressor motor to be driven does not change, so that there is an effect that no problem occurs in driving the capacitor motor.

[Brief description of drawings]

FIG. 1 is a timing diagram for explaining a control method of a vehicle air conditioner according to the present invention, FIG. 2 is a power supply system diagram of a vehicle air conditioner, FIG. 3 is a concrete circuit diagram of a DC / DC converter, and FIG. FIG. 7 is an operation explanatory diagram of the DC / DC converter. 1 is a train line, 3 is a DC / DC converter, 5a and 5b are VVVF inverter devices, 6a and 6b are compressor motors, and 7a and 7b are air conditioners. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-234401 (JP, A) JP-A-63-78872 (JP, A) JP-B 3-6025 (JP, B2)

Claims (1)

[Claims] 1. A DC / DC converter device for compensating for fluctuations in train line voltage to output a constant DC voltage, and an air conditioner for converting the DC voltage output from the DC / DC converter device into an AC voltage. Of a variable voltage / variable frequency inverter device for driving a compressor motor of the DC / DC converter device, the DC / DC converter device compensates for fluctuations of the electric line voltage above the rated voltage and fluctuations of the electric line voltage below the rated voltage. The compensation voltage is not compensated, and the variable voltage / variable frequency inverter device is configured to change the frequency so that the torque of the compressor motor is held constant when the output voltage of the DC / DC converter device decreases. A control method for a vehicle air conditioner.