JP2001025102A - Electric vehicle controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric vehicle controller which enables reduction of leakage higher harmonics, the size, weight, and cost of the devices, and the number of wires between the devices. SOLUTION: A PWM(pulse width modulation) converter device 5 is designed as a three-level type, where its direct current-side supply voltage is divided into two and four main switching elements are connected in series between the positive side and negative side of a power supply, and thereby a voltage equivalent to half the supply voltage is outputted. A VVVF inverter device 7 is designed as two-level type, where two main switching elements comprising it are connected in series between the positive side and negative side of a direct current-side power supply, and thereby a supply voltage is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle control device which uses an AC power of an AC overhead wire as a power source, converts the AC power into a variable voltage and a variable frequency AC power, and supplies the AC power to an electric motor for driving an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, for an electric vehicle traveling on an AC overhead line section, an electric vehicle which uses AC power of the overhead line as a power source, converts the AC power into a variable voltage and a variable frequency AC power, and supplies the AC power to an electric vehicle driving AC motor. A control device having the configuration shown in FIG. 4 is known.

In this conventional electric vehicle control device, AC power is taken from an AC overhead line 1 to a transformer 4 via a current collector 2 and an AC circuit breaker 3, and the AC power is stepped down by the transformer 4. This stepped-down AC power uses a self-extinguishing main switching element such as GTO, IGBT, and PWM capable of power factor control.
(Pulse Width Modulation) The converter device 5 converts the power into DC power of a predetermined voltage. This DC power is further supplied to VVVF (Variable Voltage Variable Frequecy).
It is re-converted into three-phase AC power by the inverter device 7 and
It is supplied to one or a plurality of AC motors 8 for driving an electric vehicle.
The speed of the AC motor 8 is controlled by controlling the voltage and frequency of the AC output of the VVVF inverter device 7.

[0004] The DC output side of the PWM converter device 5 and V
The DC link circuit 9 connecting the DC input side of the VVF inverter device 7 is provided with a filter capacitor 6, and the filter capacitor 6 smoothes the DC voltage.

The conventional electric vehicle control device shown in FIG. 4 has a typical circuit configuration in which the main switching elements of the PWM converter device 5 and the VVVF inverter device 7 are of a two-level system. As shown in FIG. 4, the main switching elements are QUC and Q
UX or two of each phase such as QVC and QVY are connected in series to control the voltage of the DC link circuit 9. VV
As for the VF inverter device 7, two main switching elements are connected in series, such as QU and QX, QV and QY, and QW and QZ.
A variable frequency power is supplied to control the motor speed.

On the other hand, a conventional electric vehicle control device having a configuration shown in FIG. 5 is also known. The conventional electric vehicle control device shown in FIG. 5 takes in AC power from an AC overhead line 1 to a transformer 4 via a current collector 2 and an AC circuit breaker 3 and steps down the voltage, as in the conventional example shown in FIG. Reduced AC power to PWM
The converter device 5 converts the DC power into DC power of a predetermined voltage, and further converts the DC power into three-phase AC power by the VVVF inverter device 7 and supplies the three-phase AC power to the AC motor 8 for driving the electric vehicle. The speed of the AC motor 8 is controlled by a variable voltage and a variable frequency power of the VVVF inverter device 7.

The conventional electric vehicle control device shown in FIG. 5 has a typical circuit configuration in which the main switching elements of the PWM converter device 5 and the VVVF inverter device 7 are of a three-level system. Indicate that the main switching elements are CU1 and C
Series connection of U2, CU3, CU4, CV1, CV2, C
The voltage of the DC link circuit 9 is controlled by connecting four of each phase in series like the series connection of V3 and CV4. A connection point between the main switching elements CU1 and CU2 and a connection point between the main switching elements CU3 and CU4 are connected by a circuit in which two diodes CUP and CUN are connected in series. The connection point between the two diodes CUP and CUN is called a so-called neutral point. Also, two diodes C are connected between a connection point between the main switching elements CV1 and CV2 and a connection point between the main switching elements CV3 and CV4.
VP and CVN are connected by a circuit in which they are connected in series. The connection point between the diodes CVP and CVN is also called a neutral point.

In a three-level VVVF inverter device 7 of the electric vehicle control device shown in FIG. 5, a main switching element is connected in series of IU1, IU2, IU3, IU4, and IV.
1, IV2, IV3, IV4 connected in series and IW
UVW like series connection of 1, IW2, IW3, IW4
The configuration is such that four of each phase are connected in series, and a variable voltage and a variable frequency power are supplied to the AC motor 8 to control its speed. A connection point between the main switching elements IU1 and IU2 and a connection point between the main switching elements IU3 and IU4 are connected by a circuit in which two diodes IUP and IUN are connected in series. These two diodes IUP,
The connection point between IUNs is also called a neutral point. Further, a connection point between the main switching elements IV1 and IV2 and IV3 and IV
4 and two nodes IVP, IVN
Are connected in series and the main switching element IW
The connection point between IW2 and IW2 and the connection point between IW3 and IW4 are also connected by a circuit in which two diodes IWP and IWN are connected in series.

Further, in a DC link circuit 9 connecting the DC sides of both devices 5 and 7, a filter capacitor 6 for smoothing a DC voltage is connected in series with two voltage dividing capacitors 6a and 6b having the same capacity. It is composed. The neutral point of each phase of the PWM converter device 5 and the neutral point of each phase of the VVVF inverter device 7 are compared with the neutral point indicating half the potential obtained by dividing the voltage of the DC link circuit 9. Are all connected.

[0010] By the way, a device for controlling an electric vehicle usually needs to be reduced in size and weight in order to be fitted in a limited space below the floor of the electric vehicle. For this reason, PW
It is necessary to use a large-capacity semiconductor element capable of controlling a high voltage and a large current as a main switching element constituting the M converter device and the VVVF inverter device, so that the number of components is reduced as much as possible. For the purpose of reducing the number of elements, it is advantageous to configure the electric vehicle control device in a two-level configuration shown in FIG.

On the other hand, since it is necessary to reduce the harmonic current component superimposed on the AC power supplied to the electric vehicle from the overhead line to a level lower than the malfunction level of a signal device or the like, the PWM converter device has a secondary current harmonic of the transformer. It is configured to reduce waves. For this purpose, the current waveform can be improved by using a three-level main circuit configuration, and the same effect can be obtained by increasing the switching frequency of the main switching element.

[0012] The structure of the main switching element constituting the PWM converter device and the VVVF inverter device is typically a press-contact type or a module type. The pressure resistance element has a smaller thermal resistance than the module type,
Often it is less than 2. Further, since there is no soldered joint inside the element, it is less affected by thermal fatigue due to repeated operation and stop of the electric vehicle, which is advantageous in extending the life of the device and maintenance-free.

On the other hand, the module type element can be structurally simplified since the element can be fixed to a predetermined place only with screws, and the cost of the element alone and the mounting portion thereof can be reduced. It is more advantageous than the press-contact type element in this respect.

Another point is that when the main circuit configuration of the PWM converter device and the VVVF inverter device is of a three-level system, conventionally, the DC link circuit 9 divides the power supply voltage into two and obtains a half potential, that is, Although the neutral point potential is connected between the two devices, the filter capacitors of each device are connected in parallel by connecting the neutral points of both devices, so that the voltage balance of each filter capacitor is maintained. That is, the ratio of sharing the DC voltage by １ ／ voltage is improved. However, normally, the voltage balance described above is a voltage difference of 10% of the DC link circuit voltage by the voltage control of each device, that is, the neutral point potential compensation control.
Controlled to a degree. For example, when the voltage of the DC link circuit 9 is 2000 V DC, the high voltage side is 1100 V, the constant voltage side is 900 V, and the voltage difference is 200 V around the neutral point.
Controlled to a degree.

On the other hand, in most cases, the electric vehicle control device cannot accommodate the PWM converter device 5 and the VVVF inverter device 7 in one common box due to restrictions on fitting to the vehicle body. Further, in some cases, the devices may not be mounted on the same vehicle, but may be mounted on different electric vehicles organized by a plurality of vehicles. In each case, the DC link circuit 9 between the PWM converter device 5 and the VVVF inverter device 7 is connected to the outside of the device once via the three outfitting lines including the neutral point potential. It will be wired between them. For this reason, when controlling, for example, four motors 8 for driving an electric vehicle, a current of about 1000 A flows through the three outfitting wires, so that a thick wire must be adopted. This is a major challenge. Furthermore, when the outfitting lines are wired over different vehicles, it is preferable that the number of outfitting lines is as small as possible, and two lines are far more advantageous than three.

[0016]

As described above, in order to reduce the harmonic components of the current flowing through the overhead wire to a specified value or less, it is advantageous to use a three-level main circuit configuration of the PWM converter. On the other hand, the three-level method requires twice as many main switching elements as the two-level method, which results in an increase in size and cost due to the device configuration.

As a main switching element constituting the PWM converter device and the VVVF inverter device, the press contact type element is advantageous in terms of thermal resistance, but the mounting structure is complicated, and the weight and cost are lower than the module type element. On the other hand, the module type element is easy to mount, but is disadvantageous in terms of the element life as compared with the press-contact type element because consideration must be given to thermal fatigue of the soldered portion.

Further, a PWM converter device, VVVF
When the main circuit configuration of each device of the inverter device is the three-level system, the DC link circuit between the two devices is added with one for connecting the neutral point potential in addition to the two for the high voltage side and the low voltage side of the power supply voltage. In addition, it is necessary to connect with three wires in total, and when both devices are housed in separate boxes, they are routed once between the two devices via the outside of the device. The increase increases the complexity of outfitting, making it difficult to simplify wiring, reduce weight, and reduce costs.

As described above, in the conventional electric vehicle control device,
Since the main circuit configuration of the PWM converter device and the VVVF inverter device both employs a two-level system or a three-level system, both reduce the leakage harmonics, reduce the size and weight of the device, and reduce the cost. In this case, the number of wirings between the devices is reduced, and the number of wirings between the devices is reduced. Particularly, the disadvantages are a great limitation in terms of the system configuration.

The present invention has been made in view of the above-mentioned conventional problems, and is intended to reduce the number of harmonics, reduce the size and weight of the device, reduce the cost, and reduce the number of wires between the devices. It is intended to provide a device.

[0021]

An electric vehicle controller according to the present invention comprises a PWM converter for converting an AC power supply to a DC power and outputting the DC power, and a DC frequency converter for converting the DC power output from the PWM converter to a variable frequency. A VVVF inverter device for re-converting to a variable voltage AC power and supplying power to the AC motor, a DC side of the PWM converter device and the VV
A DC link circuit that connects between the DC side of the VF inverter and the main switching element of one of the PWM converter and the VVVF inverter; The device has a three-level configuration.

According to a second aspect of the present invention, there is provided the electric vehicle control device according to the first aspect, wherein the PWM converter device divides the DC power supply voltage by two, and connects the main switching element between the positive and negative sides of the power supply. The three-level system outputs a half voltage of the power supply voltage by serially connecting the power supply voltage by two each, and the VVVF inverter device is connected in series with two main switching elements in each phase between positive and negative of the DC side power supply. Thus, the two-level system for outputting the power supply voltage is used.

According to a third aspect of the present invention, in the electric vehicle control device according to the first aspect, the PWM converter device is connected in series with two main switching elements in each phase between the positive and negative sides of a DC power source. The voltage output 2
The VVVF inverter device is divided into two levels, and the main switching elements are connected in series between the positive and negative sides of the power supply by four in each phase between the positive and negative sides of the power supply, and the neutral points are connected. Thus, the three-level system is adopted.

In the electric vehicle control apparatus according to the first to third aspects of the present invention, one of the main switching elements of the PWM converter apparatus and the VVVF inverter apparatus has a two-level configuration, and the other main switching element has a three-level configuration. By using the level system, the number of main switching elements can be reduced as compared with the case where both devices are of the three-level system, and the number of wirings of the DC link circuit can be reduced to two, thereby reducing the size, weight, and cost. The number of wires between devices can be reduced.

If the PWM converter is of a three-level type and the VVVF inverter is of a two-level type, the leakage of harmonics to the AC power source of the converter can be reduced.

Furthermore, if the PWM converter side is of a two-level system and the VVVF inverter side is of a three-level system, the motor current of the three-phase AC power supplied from the VVVF inverter to the AC motor for driving the electric vehicle. , The distortion of the motor current waveform can be reduced, and as a result, the electromagnetic distortion noise generated in the motor can be reduced as compared with the case of the two-level VVVF inverter device. Also, the motor current flows through the outfitting wiring of the electric car, but if there is a concern about the direct noise radiated from the outfitting wiring to signal equipment, etc., the three-level method has less motor current distortion, The noise level can be reduced, and the occurrence of guidance failure can be prevented.

According to a fourth aspect of the present invention, there is provided an electric vehicle control apparatus comprising: a PWM converter for converting an AC power supply into a DC power and outputting the DC power; and a DC power having a variable frequency and a variable voltage which converts the DC power output from the PWM converter. A VVVF inverter device for re-converting power to the AC motor and supplying power to the AC motor;
A DC link circuit for connecting between the DC side of the M converter device and the DC side of the VVVF inverter device. The main switching elements of the PWM converter device and the VVVF inverter device are configured to have three levels. In the DC link circuit, the positive and negative sides of the DC side of the PWM
It is connected to the positive and negative sides of the DC side of the VVF inverter device, and is not connected between the neutral points.

In the electric vehicle control device according to the fourth aspect of the present invention, P
Both the WM converter device and the VVVF inverter device have a three-level main switching element configuration. In the DC link circuit, the positive and negative DC sides of the PWM converter device are connected to the positive and negative sides of the VVVF inverter device, respectively. However, by eliminating the connection between the neutral points, the number of wirings of the DC link circuit can be reduced to two, and leakage of harmonics to the AC power supply side of the converter device can be reduced.

According to a fifth aspect of the present invention, there is provided an electric vehicle control device according to any of the first to fourth aspects, wherein one of the main switching element constituting the PWM inverter and the main switching element constituting the VVVF inverter is provided. It uses a pressure-contact type element with a capacity, and uses a module type element with a small capacity on the other side, so that it can be structurally simplified compared to the case where a pressure-contact type element is used for all main switching elements. The service life can be extended as compared with the case where a module-type element is used as the switching element.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a circuit configuration of the first embodiment of the present invention. The electric vehicle control device according to the first embodiment shown in FIG. 1 includes a conventional PWM converter device 5 having a three-level configuration shown in FIG. 5 and a conventional VVVF device having a two-level configuration shown in FIG. An inverter device 7 is provided, and the DC side of both devices 5 and 7 in the DC link circuit 9 is connected. Parts common to the circuit elements of the conventional example shown in FIGS. 4 and 5 are denoted by the same reference numerals and will be described below.

A three-level PWM converter device 5
Indicates that the main switching elements are CU1, CU2, CU3, C
The voltage of the DC link circuit 9 is controlled by connecting four units of each phase in series, such as a series connection of U4 and a series connection of CV1, CV2, CV3, and CV4. And the main switching element CU
Between CU1, CU2 and main switching elements CU3, C
The connection point between U4 is two diodes CUP, CUN
Are connected in series. A connection point between the main switching elements CV1 and CV2 and a connection point between the main switching elements CV3 and CV4 are two diodes C
VP and CVN are connected by a circuit in which they are connected in series.

The VVVF inverter device 7 of the two-level system
Controls the motor speed by connecting two main switching elements in series, such as QU and QX, QV and QY, and QW and QZ, two in each phase, and supplying a variable voltage and a variable frequency power to the AC motor 8. I do.

In the DC link circuit 9 connecting the DC sides of the devices 5 and 7, the filter capacitors 6 for smoothing the DC output of the PWM converter 5 are voltage dividing capacitors 6a and 6b for dividing the DC voltage into two. , And these neutral points are commonly connected to the neutral points of the PWM converter device 5. The positive and negative DC output terminals of the PWM converter device 5 are connected to the positive and negative DC input terminals of the VVVF inverter device 7, respectively.
However, the neutral point of the VVVF inverter device 7 and the neutral point of the PWM converter device 5 are not connected.

Thus, in the electric vehicle control device of the first embodiment, the PWM converter device 5 has three levels of voltage, that is, a DC link voltage and a half potential obtained by dividing the DC link voltage by two. That is, the neutral point potential is controlled. The VVVF inverter device 7 supplies a variable voltage and a variable frequency power to the AC motor 8 to control the motor speed.

In the first embodiment, the number of main switching elements can be reduced and the size and weight can be reduced as compared with the case where both the converter device 5 and the inverter device 7 are of a three-level system. It is easier to fit into the limited space under the floor of the electric car. Moreover, 2 of the transformer 4
The harmonic contained in the secondary current (AC) flowing between the secondary winding and the PWM converter device 5 can be reduced, and as a result, the harmonic current component superimposed on the AC power supplied from the overhead wire 1 to the electric vehicle is signaled. It can be reduced below the malfunction level of the device and the like.

In addition, since only two wires A and B connect the two devices 5 and 7 in the DC link circuit 9, when both devices 5 and 7 are housed in separate boxes. The wiring between the two devices via the outside of the device once is reduced, the number of wires is small, the outfitting becomes easy, and the wiring can be simplified, reduced in weight and reduced in cost.

Next, a second embodiment of the electric vehicle control device of the present invention will be described with reference to FIG. The electric vehicle control device according to the second embodiment includes a conventional two-level PWM converter device 5 shown in FIG. 4 and a conventional three-level VVVF inverter device 7 shown in FIG. The DC link circuit 9 is characterized in that the DC sides of both devices 5 and 7 are connected to each other.

Two-level PWM converter 5
, The main switching elements are QUC and QUX, and QVC
And QVY, two of each phase are connected in series to control the voltage of the DC link circuit 9.

A three-level VVVF inverter device 7
Means that the main switching elements are IU1, IU2, IU3, IU
Four UVW phases are connected in series, such as a series connection of U4, a series connection of IV1, IV2, IV3, and IV4, and a series connection of IW1, IW2, IW3, and IW4. And a connection point between the main switching elements IU1 and IU2;
A connection point between the main switching elements IU3 and IU4 is connected by a circuit in which two diodes IUP and IUN are connected in series. Further, the main switching elements IV1, IV2
A connection point between the connection point between IV3 and IV4 is connected by a circuit in which two diodes IVP and IVN are connected in series,
Connection point between main switching elements IW1 and IW2 and IW
Two diodes IW between the connection point between IW3 and IW4
P and IWN are connected by a circuit connected in series.

Further, in the DC link circuit 9, the DC input side of the three-level VVVF inverter device 7 is
As the filter capacitor 6 for smoothing the DC voltage, two voltage dividing capacitors 6a and 6b having the same capacity are connected in series, and the voltage obtained by dividing the voltage of the DC link circuit 9 is １ ／.
The neutral point of each phase of the VVVF inverter device 7 is connected to the neutral point indicating the potential of. The DC sides of the PWM converter device 5 and the VVVF inverter device 7 are connected by two wires A and B. However,
There is no connection between the neutral points of the two devices 5 and 7.

In the electric vehicle control device of the second embodiment, the VVVF inverter device 7 has three levels of voltage, that is, a DC link voltage and a half neutral point obtained by dividing the DC link voltage by two. AC motor 8 using electric potential
To control the speed of the electric vehicle.

According to the second embodiment, the number of main switching elements can be reduced as compared with the case where both the converter device 5 and the inverter device 7 are of a three-level system, and the size and weight can be reduced. It makes it easier to outfit the device into the limited space below the floor of the electric car. In the DC link circuit 9, the wiring connecting the two devices 5 and 7 is A and B.
Since both devices 5 and 7 are housed in different boxes, wiring is once performed between the two devices via the outside of the device, but the number of wires is small and outfitting is easy. The wiring can be simplified, lightened, and reduced in cost.

In addition, the use of the three-level VVVF inverter 7 reduces harmonic components contained in the motor current of three-phase AC power supplied from the VVVF inverter 7 to the AC motor 8 for driving the electric vehicle. However, the distortion of the motor current waveform can be reduced, and as a result, the electromagnetic distortion noise generated in the motor 8 can be reduced as compared with the case of the two-level VVVF inverter device, and in particular, about 6 dB can be reduced when the electric vehicle is started.

Although the motor current flows through the outfitting wiring of the electric vehicle, if there is a concern about the direct noise radiated from the outfitting wiring to the signal equipment, etc., the three-level method causes distortion of the motor current. Since the number is small, the noise level can be reduced, and the occurrence of an induction failure can be prevented.

Next, a third embodiment of the electric vehicle control device according to the present invention will be described with reference to FIG. The electric vehicle control device according to the third embodiment includes a PWM converter device 5, a VVV
Although the F inverter device 7 employs a three-level system, the DC link circuit 9 is characterized in that the wiring connecting the neutral points of the devices 5 and 7 is eliminated.

That is, in the DC link circuit 9, 3
2 on the DC output side of the level type PWM converter device 5.
A circuit in which the voltage dividing capacitors 6a and 6b are connected in series is inserted, and the 分 voltage dividing point of the DC output, ie, the neutral point is set to PW.
It is connected to the neutral point of each phase of the M converter device 5. A circuit in which two voltage-dividing capacitors 6c and 6d are connected in series is also inserted on the DC input side of the three-level VVVF inverter device 7, and the neutral point obtained by dividing the DC input by 1/2 is set to V.
It is connected to the neutral point of each phase of the VVF inverter device 7. However, in the DC link circuit 9, there is no connection between the connection point of the voltage dividing capacitors 6a and 6b and the connection point of the voltage dividing capacitors 6c and 6d arranged in parallel. As a result, the DC sides of the two devices 5 and 7 are connected to each other by two wires A and B.
It will be connected only by books.

As a result, when the PWM converter device 5 and the VVVF inverter device 7 cannot be accommodated in a single box due to restrictions on the fitting of the vehicle body, or each device cannot be fitted to the same vehicle, When outfitting vehicles,
The number of outfitting lines extending between devices or between vehicles can be reduced from three lines required in the conventional example shown in FIG. 5 to two lines. As a result, for example, the driving AC motor 8
When four units are controlled, it is possible to reduce the number of outfitting lines having a large diameter through which a current of about 1000 A flows, thereby reducing man-hours on outfitting, reducing costs, and reducing the space required for outfitting wiring.

In the first to third embodiments, a pressure contact element is used as a main switching element of the PWM converter device 5, and a module type element is used as a main switching element of the VVVF inverter device 7. can do.

By using a large-capacity pressure-contact type element for the PWM converter device 5 as described above, the thermal resistance of the element is less than half that of the module-type element.
When the loss generated from the element, specifically, the steady loss, the switching loss, and the like are the same, the cooling capacity of the cooling unit for suppressing the heat generation of the element can be configured to be lower by the smaller thermal resistance of the element. Further, the current flowing per element is, for example, the largest one that is practically used, and the module type element is 1200 A, while the press-contact type element is 4000 A or more. The press-contact type element is also advantageous in terms of the number of elements to be used.

On the other hand, by using a small-capacity modular type element as the main switching element of the VVVF inverter device 7, one or two AC motors 8 for driving an electric vehicle can be individually provided by one VVVF inverter device. In the case of an electric car controlled by speed, the number of main switching elements increases. However, in the case of using a pressure contact type element, means for suppressing the element from both sides with a pressure contact force of 2000 kgf or more is required for element cooling. On the other hand, the module-type element can be attached to the cooling part with about four screws, and the structure can be extremely simplified.
Cost reduction can be achieved. This has a remarkable effect particularly when a module-type element is adopted on the VVVF inverter device side where the number of elements increases.

On the contrary, in the first to third embodiments, the main switching element of the PWM converter device 5 employs a modular type element, and the main switching element of the VVVF inverter device 7 employs a press contact type. Elements can also be employed.

In an existing electric vehicle running in the AC overhead line section, a device for converting AC power into DC power from the overhead line 1 via the current collector 2, for example, a phase control rectifier using a thyristor is connected to a DC output as its output. The electric vehicle control device, which is configured to convert the electric power into three-phase AC power and connect to a VVVF inverter device that drives one or more loads connected to the output side, from the substation to the overhead line due to recent harmonic regulations. As a countermeasure against a situation in which it is necessary to reduce the harmonic components flowing through the phase control rectifier, it is effective to replace the above-described phase control rectifier with a PWM converter device 5 capable of reducing harmonics.

In such a situation, the VVVF inverter device 7 for controlling the AC motor for driving the electric vehicle is
Conventionally, the most commonly used large-capacity pressure-contact switching element, such as a GTO thyristor,
The electric vehicle control device configured by the level system is diverted from the existing one, while the device that converts AC into DC is a three-level device that can obtain the highest harmonic reduction effect from the above-described harmonic reduction request. It is effective to employ a PWM converter device configured with a small-sized modular switching element capable of setting a high switching frequency in a system.

In addition, when such a configuration is adopted, when the harmonics on the AC overhead line side are reduced with respect to the conventional electric vehicle control device, only the device for converting AC into DC is converted into a PWM converter. By replacing the device, the maximum harmonic reduction effect can be obtained, and the cost can be significantly reduced.

[0055]

As described above, according to the first to third aspects of the present invention, one of the main switching elements of the PWM converter apparatus and the VVVF inverter apparatus has a two-level configuration, and the other main switching element has the same structure. By using a three-level configuration, the number of main switching elements can be reduced as compared with the case of using a three-level configuration for both devices, and two DC link circuit wires can be used. And the number of wires between devices can be reduced.

If the PWM converter has a three-level system and the VVVF inverter has a two-level system, the leakage of harmonics to the AC power supply of the converter can be reduced.

Further, if the PWM converter side is of a two-level type and the VVVF inverter side is of a three-level type, the motor current of three-phase AC power supplied from the VVVF inverter to the AC motor for driving the electric vehicle can be obtained. , The distortion of the motor current waveform can be reduced, and as a result, the electromagnetic distortion noise generated in the motor can be reduced as compared with the case of the two-level VVVF inverter device. Also, the motor current flows through the outfitting wiring of the electric car, but if there is a concern about the direct noise radiated from the outfitting wiring to signal equipment, etc., the three-level method has less motor current distortion, The noise level can be reduced, and the occurrence of guidance failure can be prevented.

According to the fourth aspect of the present invention, both the PWM converter and the VVVF inverter have a three-level configuration of their main switching elements. In the DC link circuit, each of the positive and negative sides of the DC side of the PWM converter is provided. Is connected to the positive and negative sides of the DC side of the VVVF inverter device, and the neutral point is not connected.
The number of wires of the DC link circuit can be reduced to two, and leakage of harmonics to the AC power supply side of the converter device can be reduced.

According to the fifth aspect of the present invention, in addition to the effects of the first to fourth aspects of the present invention, one of the main switching element constituting the PWM inverter and the main switching element constituting the VVVF inverter is provided. The use of large-capacity pressure-contact elements and the use of small-capacity modular elements on the other side contributes to structural simplification, compactness, and lighter weight than when pressure-contact elements are used for all main switching elements. In addition, the life can be extended as compared with the case where the module type elements are employed for all the main switching elements.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram according to a first embodiment of the present invention.

FIG. 2 is a circuit block diagram according to a second embodiment of the present invention.

FIG. 3 is a circuit block diagram according to a third embodiment of the present invention.

FIG. 4 is a circuit block diagram of a conventional example.

FIG. 5 is a circuit block diagram of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Overhead wire 2 Current collector 4 Transformer 5 PWM converter device 6 Filter capacitor 6a-6d Voltage dividing capacitor 7 VVVF inverter device 8 AC motor 9 DC link circuit A wiring B wiring

Claims (5)

[Claims] 1. A PWM converter for converting an AC power supply into a DC power and outputting the DC power, and a DC power output from the PWM converter is reconverted into a variable frequency and a variable voltage AC power to supply the AC motor. VVVF inverter device, the DC side of the PWM converter device and the V
In an electric vehicle control device including a DC link circuit connecting between a DC side of a VVF inverter device and a main switching element of one of the PWM converter device and the VVVF inverter device, a configuration of a two-level system is used. An electric vehicle control device, wherein the configuration of the other main switching element is a three-level system. 2. The PWM converter device according to claim 1, wherein the DC side power supply voltage is divided by two, and the main switching elements are connected in series by four in each phase between the positive and negative sides of the power supply, so that the voltage is 電 圧 of the power supply voltage. The VVVF inverter device is configured to output the power supply voltage by connecting two main switching elements in series between each of the positive and negative DC power supplies in each phase. The electric vehicle control device according to claim 1, wherein: 3. The PWM converter device according to claim 2, wherein the power supply voltage is output by connecting two main switching elements in series between each of positive and negative DC power supplies in each phase.
The VVVF inverter device divides the DC-side power supply voltage by two, and connects the main switching elements in series by four in each phase between positive and negative of the power supply, and connects between the neutral points. The electric vehicle control device according to claim 1, wherein the three-level system is used. 4. A PWM converter for converting AC power into DC power and outputting the DC power, and re-converting DC power output from the PWM converter into AC power having a variable frequency and a variable voltage to supply the AC motor. VVVF inverter device, the DC side of the PWM converter device and the V
In an electric vehicle control device comprising a DC link circuit connecting between a DC side of a VVF inverter device, a configuration of a main switching element of the PWM converter device and the VVVF inverter device is a three-level system. In the DC link circuit, the positive and negative sides of the DC side of the PWM converter device are connected to the positive and negative sides of the DC side of the VVVF inverter device, respectively, and the neutral point is not connected. 5. A large-capacity pressure-contact type element is used for one of a main switching element constituting the PWM inverter device and a main switching element constituting the VVVF inverter device, and a small-capacity modular element is used for the other. The electric vehicle control device according to any one of claims 1 to 4, wherein: