JP3095486B2 - Electric vehicle power converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter for receiving power from an overhead line and supplying desired power to a load of an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, an air conditioner for an electric vehicle, a compressor for compressing air used for controlling the electric vehicle, an illumination light in the vehicle,
As an example of a power supply device that supplies power to a load such as a power supply of a control device, there is one configured as follows.
That is, a transformer device including a pantograph, an inverter device in which a plurality of voltage-dividing inverters are connected in series, and a plurality of transformers provided correspondingly to the voltage-dividing inverters and having a secondary side connected in series with power from the overhead line. Are sequentially supplied to the load via the power supply.

FIG. 4 is a diagram showing a schematic configuration of a conventional transformer device used in a power supply device having such a configuration, which is independent of iron cores 21A, 21B, 21C for each inverter.
The three-phase primary winding AU is provided in each of the cores 21A to 21C.
1, AV1, AW1 and three-phase secondary winding AU2, AV2, A
W2, three-phase primary windings BU1, BV1, BW1, three-phase secondary windings BU2, BV2, BW2, three-phase primary windings CU1, C
V1, CW1 and three-phase secondary windings CU2, CV2, CW2 are wound respectively, and these secondary windings AU2, AV2, A
W2, BU2, BV2, BW2, CU2, CV2, CW
2 are connected in series for each phase, and the output terminals u, v, w are connected to a load (not shown). Note that U
A, VA, WA, UB, VB, WB, UC, VC, WC
Is an input terminal connected to an inverter not shown, IU
V, IVW, and IWU are primary currents, Eu is a primary voltage, and EU is a secondary voltage. φU, φV, φw are magnetic fluxes.

[0004]

As described above, since the load of the electric vehicle is supplied with power via the overhead line and the pantograph, the load of the electric vehicle is influenced by other electric vehicles running in the same feeder section, and the driving of the electric vehicle itself is performed. The voltage of the input power supply fluctuates greatly and steeply due to the influence of the main circuit for this purpose and the effect of contact between the overhead wire and the pantograph.

[0005] The load of the power supply device of the electric vehicle is varied, as described above, such as an air conditioner, a compressor for compressing air used for controlling the electric vehicle, a fluorescent lamp used for lighting the inside of the vehicle, and a power supply for control equipment. It is.

For this reason, the transformer device constructed as shown in FIG.
When an imbalance occurs in the secondary voltage and the imbalance occurs in the primary voltage of the transformer, the voltage is output to the secondary voltage of the transformer.

[0007] In view of the above, the fluctuating voltage is taken into the control and a control command is issued to each inverter, thereby promoting the voltage imbalance and fluctuation of the three-divided inverter.
The imbalance causes the inverter to become overvoltage, causing the system to stop and cause a failure. In particular, because it is used as a power source for fluorescent lights used for lighting in cars and compressors for compressing air used for controlling electric vehicles, long-term stoppages and breakdowns will significantly reduce passenger service. .

An object of the present invention is to provide an electric vehicle power converter capable of correcting a voltage imbalance of a plurality of voltage-dividing inverters due to an abrupt change in overhead lines or loads that causes system stoppage or failure. Aim.

[0009]

According to the present invention, in order to achieve the above object, DC power from an overhead line is converted into AC by an inverter device in which a plurality of voltage-dividing inverters are connected in series via a pantograph. The output voltage of the voltage-dividing inverter is synthesized by a transformer provided for each voltage-dividing inverter and supplied to a load. The transformer has a common iron core, and a primary winding corresponding to each of the voltage-dividing inverters is provided on the iron core. Control means for winding and integrating the wire and the secondary winding respectively, giving the same control signal to each of the voltage dividing inverters in the same phase, and making the output voltages of the voltage dividing inverters the same. Things.

[0010]

According to the present invention, the same control signal is supplied to a plurality of voltage dividing inverters in the same phase, the output voltages of the voltage dividing inverters are made the same, and the transformers for synthesizing the output voltages are the same. Since it is wound around the iron core, it is possible to correct the voltage imbalance of the voltage dividing inverter caused by the influence of the overhead wire and the load.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention. The power of the overhead wire 1 is supplied to various loads 11 via the following elements in order. That is, the pantograph 2, the unit switch 3, the DC filter reactor 4, the parallel circuit of the unit switch 5 and the resistor 6,
DC filter capacitors 71, 72, 73 and three inverters 81, 82, 83 are connected in series, and are connected to an inverter device 8 for obtaining DC three-phase AC output, and inverters 81 to 83, respectively. AC filters (AC filters) 91, 92, 93 and the respective AC filters 91 to 93, respectively, and a primary winding AU wound around a three-phase tripod core 100 as described later.
1, AV1, AW1, BU1, BV1, BW1, CU
1, CV1, CW1, and each connected in series,
And the secondary winding AU2 wound around the same iron core 100.
AV2, AW2, BU2, BV2, BW2, CU2, C
The transformer 10 has V2 and CW2.

FIG. 2 is a diagram showing a specific configuration of the transformer 10, and includes three legs 100L1, 100L2, 100
L3 and the same three-phase tripod core 100 having two yoke portions 100Y1 and 100Y2 are connected to the primary windings AU1 to AU1 described above.
CW1 and secondary windings AU2 to CW2 are wound around their legs 100L1, 100L2, 100L3, respectively, and they are connected as follows. That is, the primary windings AU1 to AW1 are Δ-connected, and the connection point of each winding is connected to the AC filter terminals U1, V1, W1. Further, the primary windings BU1 to BW1 are Δ-connected, and the connection points of the respective windings are filter terminals U2, V2, W
2 are connected. Further, the primary windings CU1 to CU1
Are connected by Δ, and a part thereof is connected to an AC filter terminal U.
3, V3, and W3. And the secondary winding A
U2 to CW2 are composed of AU2, BU2 and CU2 connected in series to form a first phase winding, and AV2, BV2 and C
V2 is connected in series to form a second phase winding, AV2, BV2 and CV2 are connected in series to form a third phase winding, one end of each phase winding is Y-connected, and The ends are connected to load terminals u, v, w.

The operation of the power conversion device for an electric vehicle configured as described above will be described below. Now, consider a case where the inverters 81 to 83 are operated in the same phase to make the voltage induced on the primary side of the transformer 10 the same. At this time, the output voltages of the inverters 81-83 are used to determine the AC filters 91-9.
The magnetic flux φ generated in the iron core 100 via No. 3 is as follows: φ = V / 4.44fN (1) Where V: primary voltage of the transformer 10 f: frequency N: number of turns

From the equation (1), since the magnetic flux φ induced from each of the inverters 81 to 83 becomes the same by the in-phase operation, the iron core of the transformer which has been conventionally divided into three can be integrated.

Then, by integrating the iron core 100,
Even if the primary voltage of the transformer 10 fluctuates sharply, the core 10
Since the same magnetic flux is generated in the inverters 81 to 81,
The primary voltage V of the transformer 10 of 83 operates so as to be the same voltage. Thereby, the voltage imbalance of each of the inverters 81 to 83 can be corrected.

FIG. 3 is a block diagram showing control means for the inverters 81 to 83. The output voltage of the inverter is obtained by using a voltage command output from a voltage commander 12 for giving a voltage to be output and a voltage deviation of the output voltage of the transformer 10 using an adder 13. It is controlled by a configuration in which a phase command is given to each of the inverters 81 to 83 so as to be zero.

At this time, the magnetic flux φ generated in the core 100 of the transformer 10 from the output voltages of the inverters 81 to 83 via the AC filters 91 to 93 is expressed by the following equations (2) to (5). φ1 = V1 / 4.44fN (2) φ2 = V2 / 4.44fN (3) φ3 = V3 / 4.44fN (4) φ = φ1 = φ2 = φ3 (5) where φ1: inverter 81 Φ2: Magnetic flux generated by inverter 82 φ3: Magnetic flux generated by inverter 83 V1: Voltage generated by inverter 81 V2: Voltage generated by inverter 81 V3: Voltage generated by inverter 81

In the case of the auxiliary power supply, the command frequency is 60H
z, and if the number of turns of the transformer 10 is the same, the magnetic flux φ generated in the iron core 100
８３83 is proportional to the output voltage.

Further, as shown in FIG. 3, by operating each of the inverters 81 to 83 in the same phase, the primary voltage of the transformer 10 becomes equal to V1 = V2 = V3.
As can be seen from equation (4), the magnetic flux generated in the iron core 100 is also equal. In addition, since the induced magnetic flux generated from each of the inverters 81 to 83 is the same, the iron core of the transformer that has been conventionally divided into three can be integrated.

By integrating the core of the transformer, even if the primary voltages V1, V2, V3 of the transformer 10 fluctuate sharply or imbalance occurs, the core 100
Since the same magnetic flux φ is generated in each of the inverters 81 to 81
The primary voltages V1, V2, and V3 of the transformers 83 operate to have the same voltage. As a result, the voltage imbalance of the three-divider inverters 81 to 83 can be corrected, and the voltage generated on the secondary side of the transformer 10 does not fluctuate sharply. For this reason, the voltage imbalance of each of the inverters 81 to 83 is not promoted with respect to a steep overhead wire or a change in load, and the voltage can be made to stabilize the voltage balance. Further, since the conventional three independent iron cores are integrated, the size and weight of the transformer 10 can be reduced, which leads to a reduction in the size and weight of the system.

In the embodiment described above, the three-divided voltage inverters 81 to 83 have been described. However, other multi-divided voltage inverters may be operated by operating the multi-divided voltage inverters in the same phase and integrating the transformer core. The same effect can be obtained.

[0022]

According to the present invention, even if a steep change or a load change in the overhead line, which is peculiar to an electric vehicle that receives power supply from the overhead line, occurs, the inverters having a plurality of partial voltages are operated in the same phase, and the iron core of the transformer is used. By winding each primary winding and each secondary winding around this, it is possible to prevent the system from being stopped or malfunctioning by preventing overvoltage of each inverter with multiple voltage divisions. In addition, it is possible to reduce the size and weight of the transformer, thereby providing an electric vehicle power converter that contributes to the reduction in size and weight of the system.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a power conversion device for an electric vehicle according to the present invention.

FIG. 2 is a configuration diagram showing a specific example of the transformer in FIG. 1;

FIG. 3 is a block diagram for explaining control of the inverter of FIG. 1;

FIG. 4 is a configuration diagram showing an example of a transformer device used for a conventional power conversion device for an electric vehicle.

[Explanation of symbols]

1 ... overhead wire, 2 ... pantograph, 3 ... unit switch, 4 ...
DC filter reactor, 5 unit switch, 6 resistor, 7 DC filter capacitor, 81-83 inverter, 91-93 AC filter, 10 transformer, 1
1 ... Load, 12 ... Voltage commander, 13 ... Adder, 14 ... Feedback control term.

Claims (1)

(57) [Claims] 1. A DC power from an overhead line is converted into AC by an inverter device in which a plurality of voltage-dividing inverters are connected in series via a pantograph, and an output voltage of each voltage-dividing inverter is converted to an AC voltage corresponding to each voltage-dividing inverter. In a transformer synthesized by the provided transformer and supplied to a load, the transformer has a common iron core, and a primary winding and a secondary winding corresponding to each of the voltage-dividing inverters are wound around the iron core and integrated, A power conversion device for an electric vehicle, comprising: control means for providing the same control signal in phase with each of the voltage-dividing inverters and for making the output voltages of the voltage-dividing inverters the same.