Electric vehicle propulsion control device

Abstract

Electric vehicle propulsion control device (100), with: a filter device (5, 12); and a power converter (6), wherein the filter device (5, 12) is configured such that: a first inductive element (L1) and a capacitive element (C) are connected in series to create a series circuit; one end of the series circuit is electrically connected to a low-potential-side power supply cable that connects a rail (2) and the power converter (6); another end of the series circuit is electrically connected to a high-potential-side power supply cable (4a) that connects a high-voltage line (1) and the power transformer (6); and a second inductive element (L2) provided between an electrical connection point of the other end of the series connection and the high-voltage line (1), and the first inductive element (L1) are magnetically coupled together, and the magnetic coupling creates a mutual inductance (M) which has a positive value between the electrical connection point and the power transformer (6).

Description

Area

[0001] The present invention relates to an electric vehicle propulsion control device comprising a filter device and a power converter. background

[0002] An electric vehicle traction control device includes a power converter that receives electrical power supplied from a power supply and drives a motor using the received electrical power. The power converter has a converter element therein. The switching operation of the converter element of the power converter causes a return current containing an oscillating current to flow through the rail, which is the return path to a substation serving as the power supply. Oscillating components contained in the return current can cause malfunctions in track safety equipment, including crossing control devices and signals, that are already installed. For this reason, there is sometimes a need to dampen the oscillating components contained in the return current.

[0003] In view of the above-described technical background, Patent Literature 1 discloses a method for damping vibration components contained in the return current over a relatively wide frequency range, i.e., around several hundred hertz. Patent Literature 1 also discloses a control device for driving an electric vehicle that uses a power converter to convert electrical energy from a direct current source into alternating current.The DC filter is composed of a first reactor and a second reactor connected in series between positive input and output terminals and having magnetic coupling, a first capacitor provided between output terminals, and a third reactor and a second capacitor connected in series between the series connection point of the first and second reactors and a negative-side terminal. DC electric power supplied via a lead wire and a bus bar is collected by a collector to be fed into the power converter via a switch and the reactor and capacitor, which constitute the DC filter. Patent Literature 2 relates to a filter device and a drive controller for electric vehicles. Patent Literature 3 relates to a noise suppression circuit. Citation listPatent literature Patent literature 1: JP 2002-315 101 A Patent literature 2: JP 2015-146 603 A Patent literature 3: JP 2005-117 218 A. Brief descriptionTechnical problem

[0004] As represented by the above Patent Literature 1, conventional techniques for damping vibration components have focused on damping vibration components over a wide frequency range rather than focusing on damping. Therefore, sufficient damping is not available for damping vibration components in a relatively narrow frequency range within a specific frequency band, and therefore, new techniques are needed.

[0005] The present invention has been made in view of the foregoing, and an object of the present invention is to provide an electric vehicle propulsion control device having a filter device that can ensure sufficient attenuation of vibration components in a relatively narrow frequency range in a certain frequency band. Solution to the problem

[0006] In order to solve the above problem and achieve the object, an electric vehicle propulsion control device according to the independent claims is provided. Advantageous effects of the invention

[0007] According to the present invention, it is possible to ensure sufficient attenuation of vibration components in a relatively narrow range in a certain frequency band. Short description of the drawings Fig. 1 is a diagram showing the configuration of an entire electric vehicle drive system including an electric vehicle propulsion control device according to a first embodiment. Fig. 2 shows an equivalent circuit diagram explaining the filtering operation of the electric vehicle propulsion control device according to the first embodiment. Fig. 3 is a diagram showing the frequency characteristics of a reverse current according to the first embodiment. Fig. 4 is a diagram showing the configuration of an electric vehicle propulsion control device according to a second embodiment. Description of embodiments

[0008] Hereinafter, an electric vehicle propulsion control device according to embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments. First embodiment.

[0009] Fig. 1 is a diagram illustrating the configuration of an entire electric vehicle drive system including an electric vehicle propulsion control device according to a first embodiment. Fig. 1, an electric vehicle propulsion control device 100 according to the first embodiment includes, as main components, a filter circuit 5, a power converter 6, and a first reactor 12. The filter circuit 5 and the first reactor 12 constitute a filter device. The first reactor 12 includes a reactor core 12a and a winding portion 12b. The power converter 6 is connected to a motor 7 via a connecting cable 9. The motor 7 is a three-phase motor and provides propulsion power for an electric vehicle.

[0010] One end of the electric vehicle propulsion control device 100 is connected to a high-voltage line 1 via a high-potential side feeder 4a and a current collector 3. The other end of the electric vehicle propulsion control device 100 is connected to a rail 2 via a low-potential side feeder 4b and a wheel 8. A power supply cable 14, which electrically connects the feeders 4a and 4b and the power converter 6, is installed in the electric vehicle propulsion control device 100. With this configuration, DC power supplied from the high-voltage line 1 is supplied to the power converter 6 via the feeders 4a and 4b and the power supply cable 14. The power converter 6 converts DC power supplied from the high-voltage line 1 into AC power having a given frequency and voltage to drive the motor 7.

[0011] Next, the configuration of the filter device in the electric vehicle propulsion control device 100 according to the first embodiment will be described.

[0012] A capacitor 10a and a second reactor 10b are connected in series to form a series circuit part 10A. One end of the series circuit part 10A is connected to a ground wire 14c, which is a low-potential side power supply wire.

[0013] Furthermore, the electric wire drawn from the other end of the series circuit part 10A, that is, a filter wire 18 of the filter circuit 5, is wound around the reactor core 12a to form the winding portion 12b of the first reactor 12. After forming the winding portion 12b, the filter wire 18 is connected to the high-potential side power supply cable 14.

[0014] Here, if the point where the filter line 18 is connected to the high-potential-side power supply cable 14 is a connection point 16, then the high-potential-side power supply cable 14 is split into two parts at the connection point 16. One of the two parts is referred to as a first cable part 14a, and the other is referred to as a second cable part 14b. Specifically, the first cable part 14a is the part installed between the connection point 16 and the power converter 6, and the second cable part 14b is the part installed between the connection point 16 and the end portion of the high-potential-side supply cable 4a.

[0015] The choke core 12a is made of a magnetic material. A suitable magnetic material is an amorphous ferrite material or a dust core obtained by finely crushing and solidifying iron. The choke core 12a is formed in a semicircular shape and arranged to cover the second cable part 14b. This means that the choke core 12a is arranged to cover a part of the power supply cable 14 on the side closer to the overhead line 1 than the connection point 16.

[0016] In the series circuit part 10A, the connection order of the capacitor 10a and the second reactor 10b may be reversed. Specifically, in the opposite direction of the drawing, one end of the capacitor 10a may be electrically connected to the high-potential side power supply cable 14 via the first reactor 12, and one end of the second reactor 10b may be electrically connected to the low-potential side power supply cable 14.

[0017] Hereinafter, a further description of the first reactor 12 is provided. In the foregoing description, the shape of the reactor core 12a was described as a semicircular shape, but the shape of the reactor core 12a is not necessarily required to be a semicircular shape. The shape of the reactor core 12a can be any shape as long as the reactor core 12a does not completely cover the periphery of the second wire portion 14b of the power supply wire 14. That is, as long as the reactor core 12a has an opening, the reactor core 12a of the present embodiment can have any shape.

[0018] Next, the winding direction of the winding portion 12b formed in the first reactor 12 will be described. When a noise current flows through the first wire portion 14a of the power supply wire 14, the noise current also flows into the winding portion 12b. The winding direction of the winding portion 12b is determined so that the magnetic flux (referred to as "first magnetic flux" for convenience) generated in the reactor core 12a by the noise current flows through the first wire portion 14a, and the magnetic flux (referred to as "second magnetic flux" for convenience) generated in the reactor core 12a by the noise current and flowing through the winding portion 12b cancel each other out. That is, the winding portion 12b is wound in a direction such that the first magnetic flux and the second magnetic flux generated in the choke coil core 12a cancel each other.In the winding section 12b, it is preferable that the number of turns of the filter wire 18 wound around the choke coil core 12a be two or more. If the number of turns is two or more, it is easy to make the inductance of the first choke coil 12 larger than the inductance of the second choke coil 10b. If the inductance of the first choke coil 12 is larger than the inductance of the second choke coil 10b, the second choke coil 10b can be omitted.

[0019] Fig. 2 shows an equivalent circuit diagram explaining the filter operation of the electric vehicle propulsion control device 100 according to the first embodiment. In Fig. 2 are the same components as those in Fig. 1 are designated by the same reference numerals.

[0020] As described above, the first magnetic flux generated in the choke core 12a by the current flowing through the first cable portion 14a and the second magnetic flux generated in the choke core 12a by the current flowing through the filter wire 18 act in directions such that they cancel each other out. For this reason, mutual inductance M occurs in the first cable portion 14a in an electrical circuit. Here, the polarity of the mutual inductance M is "positive." Therefore, if the self-inductance of the winding portion 12b is denoted by L1, then the inductance generated in the winding portion 12b is L1-M. Similarly, if the self-inductance in the second cable portion 14b is denoted by L2, then the inductance generated in the first cable portion 14a is L2-M.In addition, the capacitance of the capacitor 10a constituting the filter circuit 5 is denoted by C, and the inductance of the second choke coil 10b is denoted by L. These constitute the equivalent circuit shown in FIG. Fig. 2. Because the self-inductance of the second cable part 14b is small compared to the mutual inductance M and is therefore assumed to be zero, the self-inductance in the first cable part 14a is not in the equivalent circuit in Fig. 2 shown.

[0021] Next, with reference to the Fig. 2 and Fig. 3, the operation of the main components of the electric vehicle propulsion control device 100 according to the first embodiment will be described. Fig. 3 is a diagram showing the frequency characteristics of a reverse current I2 according to the first embodiment.

[0022] The power converter 6 has a converter element 6a therein. Due to the switching operation of the converter element 6a, a noise current I flows through the power supply cable 14. The noise current I is divided into a filter circuit current I1, which is a current component flowing toward the filter circuit 5, and a return current I2, which is a current component flowing toward the high-voltage line 1. The Fig. 3 shows the frequency characteristics of the reverse current I2. In the Fig. 3, the frequency at which the reverse current I2 is maximum is called the anti-resonance frequency and is denoted by f1. The frequency at which the reverse current I2 is minimum is called the resonant frequency and is denoted by f2.

[0023] As in Fig. 3, the antiresonance frequency f1 is a frequency at which the reverse current I2 has a maximum value I maxThe reverse current I2 reaches a maximum value when the filter circuit current I1 is at its smallest, that is, when the mutual inductance M and the series connection of the inductance L1-M generated in the winding section 12b, the capacitance C of the capacitor 10a, and the inductance L of the second choke coil 10b cause parallel resonance. Therefore, the anti-resonance frequency f1 can be expressed by the following formula: f1=1 / 2π{√[M+(L1−M)+L]⋅C}=1 / 2π{√(L1+L)⋅C}

[0024] As in Fig. 3, the resonance frequency f2 is a frequency at which the reverse current I2 has a minimum value I minThe reverse current I2 assumes a minimum value when the filter circuit current I1 is at its largest, that is, when the inductance L1-M generated in the winding section 12b, the capacitance C of the capacitor 10a, and the inductance L of the second choke coil 10b cause series resonance. Therefore, the resonance frequency f2 can be expressed by the following formula: f2=1 / 2π{√(L1−M+L)⋅C}

[0025] In Fig. 3, the frequency band in which it is desirable to ensure attenuation is the frequency band f2±Δf around the resonance frequency f2. Therefore, by determining the circuit elements of the filter circuit 5 and the first choke coil 12 according to the frequency in the frequency band in which it is desirable to ensure attenuation, the desired filter operation becomes possible.

[0026] The electric vehicle propulsion control device 100 according to the first embodiment is suitable for use with the power converter 6 in which the converter element 6a is configured from a wide-bandgap semiconductor. A wide-bandgap semiconductor is a generic term for semiconductors including gallium nitride (GaN), silicon carbide (SiC), and diamond. Because the withstand voltage characteristics and the allowable current density of the converter element 6a are increased by using a wide-bandgap semiconductor for the converter element 6a, it is possible to downsize the converter element 6a and to downsize a semiconductor module including such elements. In addition, because a wide-bandgap semiconductor has high thermal resistance, it is also possible to downsize the cooler that therefore cools the converter element 6a.

[0027] Using a wide-bandgap semiconductor for the conversion element 6a will be a future trend. With the technique according to the first embodiment, because the first choke coil 12 can be arranged within the relatively large space where the power supply cable 14 is installed, it is possible to avoid increasing the size of the housing for the power converter 6. As described above, the technique according to the first embodiment is useful when used with the power converter 6 in which the conversion element 6a is configured with a wide-bandgap semiconductor.

[0028] As described above, the electric vehicle propulsion control device according to the first embodiment includes the first reactor having the reactor core with an opening and the winding portion having the filter line wound around the reactor core. One end of the winding portion of the first reactor is electrically connected to a first cable, which is a high-potential side power supply cable, connecting the high-voltage line and the power converter, and the other end of the winding portion is electrically connected, via the filter circuit, to a second cable, which is a low-potential side power supply cable, connecting the busbar and the power converter.An inductive element is provided between the electrical connection point of the first choke coil to the first cable and the high-voltage line, and the first choke coil is configured to be magnetically coupled to the inductive element. The winding portion is configured such that the magnetic coupling generates a mutual inductance having a positive value between the power converter and the electrical connection point of the first choke coil to the first power supply cable. With this configuration, since a signal in a certain frequency band may be attenuated due to the resonance phenomenon, it is possible to ensure sufficient attenuation of an oscillation component in a relatively narrow frequency range in a certain frequency band.

[0029] Furthermore, with the electric vehicle propulsion control device according to the first embodiment, because the mutual inductance M between the power converter and the electrical connection point of the first reactor with the first power supply cable can be generated only by adding the first reactor, it is possible to ensure attenuation of vibration components included in a return current without adding a physical inductive element between the power converter and the filter circuit, which is a noise current bypass circuit.

[0030] Furthermore, with the electric vehicle propulsion control device according to the first embodiment, because the first reactor is added to connect an inductance element in series with the filter circuit, which is a noise current bypass circuit, it is possible to make the inductance elements in the filter circuit smaller or reduce the number of inductance elements in the filter circuit and thereby downsize the filter circuit.

[0031] Note that the Fig. 1 illustrated configuration is an example, and the configuration shown in Fig. 2, in which the equivalent circuit is formed, is one aspect of the present invention. That is, one aspect of the present invention is a configuration having the filter device configured such that the first inductance element L1, the third inductance element L, and the capacitance element C are connected in series to form a series circuit; wherein one end of the series circuit is electrically connected to the low-potential side power supply cable connecting the busbar and the power converter; wherein the other end of the series circuit is electrically connected to the high-potential side power supply cable connecting the high-voltage line and the power converter; wherein the second inductance element L2, provided between the electrical connection point of the other end of the series circuit and the high-voltage line, and the first inductance element L1 are magnetically coupled to each other;and wherein the magnetic coupling creates the mutual inductance having a positive value between the electrical connection point of one end of the series circuit and the power converter;

[0032] Furthermore, in the equivalent circuit shown in Fig. 2, the third inductive element L can be omitted. Therefore, another aspect of the present invention is a configuration having the filter device configured such that the first inductive element L1 and the capacitive element C are connected in series to establish the series circuit; wherein one end of the series circuit is electrically connected to the low-potential side power supply cable connecting the busbar and the power converter; wherein the other end of the series circuit is electrically connected to the high-potential side power supply cable connecting the high-voltage line and the power converter; wherein the second inductive element L2 provided between the electrical connection point of the other end of the series circuit and the high-voltage line and the first inductive element L1 are magnetically coupled to each other;and wherein the magnetic coupling creates the mutual inductance having a positive value between the electrical connection point of one end of the series circuit and the power converter; Second embodiment.

[0033] Fig. 4 is a diagram illustrating the configuration of an electric vehicle propulsion control device according to a second embodiment. Fig.4, the electric vehicle propulsion control device 100 according to the second embodiment is different from the electric vehicle propulsion control device 100 according to the first embodiment in that the position of the connection point 16 is different. While the connection point 16 is arranged on the power supply cable 14 connecting the supply 4a and the power converter 6 in the first embodiment, the connection point 16 is arranged inside the power converter 6 or at an end portion (not shown) in a second embodiment. The end portion of the power converter 6 according to the present embodiment means the portion where the power supply cable 14 is connected to the power converter 6. This means that the connection point 16 is provided in the power converter 6 in the second embodiment.

[0034] Now, the significance of the connection point 16 being provided in the power converter 6 will be described. The power converter 6 is a source of noise. For this reason, there are many requirements for taking countermeasures against the noise near the noise source. In other words, when designing the power converter 6, noise countermeasures are often considered in the user requirements. If the connection point 16 is arranged in the power converter 6, the first reactor 12 can be arranged near or inside the power converter 6. This means that by disposing the connection point 16 in the power converter 6, there is an advantage in that the degree of freedom in the design regarding the arrangement of the first reactor 12 is increased.

[0035] By incorporating the first reactor 12 in the power converter 6, it is possible to obtain an effect such that a holding mechanism for holding the first reactor 12 can be easily manufactured.

[0036] Furthermore, by disposing the connection point 16 in the end portion of the power converter 6, it is possible to obtain an effect that the connection point 16 can be configured without a special connection mechanism in the power supply cable 14. List of reference symbols

[0037] 1 Overhead line; 2 Rail; 3 Current collector; 4a, 4b Supply; 5 Filter circuit; 6 Power converter; 6a Converter element; 7 Motor; 8 Wheel; 9 Connection cable; 10a Capacitor; 10b Second reactor; 10A Series circuit part; 12 First reactor; 12a Reactor core; 12b Winding section; 14 Power supply cable; 14a First cable part; 14b Second cable part; 16 Connection point; 18 Filter line; 100 Electric vehicle propulsion control device.

Claims

[1] Electric vehicle propulsion control device (100), comprising: a filter device (5, 12); and a power converter (6), wherein the filter device (5, 12) is configured such that: a first inductive element (L1) and a capacitive element (C) are connected in series to form a series circuit; one end of the series circuit is electrically connected to a low-potential side power supply cable connecting a rail (2) and the power converter (6); another end of the series circuit is electrically connected to a high-potential side power supply cable (4a) connecting a high-voltage line (1) and the power converter (6); and a second inductive element (L2) provided between an electrical connection point of the other end of the series circuit and the high-voltage line (1), and the first inductive element (L1) are magnetically coupled to each other, and the magnetic coupling generates a mutual inductance (M) having a positive value between the electrical connection point and the power converter (6). [2] The electric vehicle propulsion control device (100) according to claim 1, further comprising a third inductive element (L) connected in series with the first inductive element (L1). [3] Electric vehicle propulsion control device (100), comprising: a filter device (5, 12); and a power converter (6), wherein the filter device (5, 12) comprises: a filter circuit (5) comprising a capacitor (10a); and a first choke coil (12) having a choke coil core (12a) having an opening and a winding portion (12b) having a filter line (18) wound around the choke coil core (12a), and the winding section (12b) is configured such that: one end of the winding portion (12b) is electrically connected to a high-potential side power supply cable (4a) connecting a high-voltage line (1) and the power converter (6); another end of the winding portion (12b) is electrically connected, via the filter circuit (5), to a low-potential side power supply cable (4b) connecting a rail (2) and the power converter (6); and an inductive element which is magnetically coupled between an electrical connection point (16) of one end of the winding section (12b) with the high-potential side power supply cable (4a) and the high-voltage line (1) and the first reactor (12), and the magnetic coupling generates a mutual inductance (M) having a positive value between the electrical connection point (16) and the power converter (6). [4] The electric vehicle propulsion control device (100) according to claim 3, wherein the filter circuit (5) includes a second reactor (10b) connected in series with the capacitor (10a). [5] The electric vehicle propulsion control device (100) according to any one of claims 1 to 4, wherein the electrical connection point (16) is provided in the power converter (6). [6] The electric vehicle propulsion control device (100) according to any one of claims 1 to 5, wherein a converter element (6a) constituting the power converter (6a) is configured from a wide bandgap semiconductor. [7] The electric vehicle propulsion control device (100) according to claim 6, wherein the wide band gap semiconductor is gallium nitride, silicon carbide or diamond.

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