JP2022148644A - Dc power generation system and railway vehicle power supply system - Google Patents

Abstract

To provide a technology capable of implementing downsizing and high output power in a DC power generation system in which a permanent magnet synchronous generator and a full-wave rectifier are combined.SOLUTION: A DC power generation system 1 comprises: a permanent magnet synchronous generator 3; a rectifier 7 for performing full-wave rectification on alternating current output from the permanent magnet synchronous generator 3 to direct current; and a capacitor circuit part 5 having capacitors inserted into respective phases of an AC line connecting the permanent magnet synchronous generator 3 with the rectifier 7. Operation control of the permanent magnet synchronous generator 3 is performed at rotation speed corresponding to a resonant frequency of an LC circuit configured by the capacitors and reactance of the permanent magnet synchronous generator 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to a DC power generation system and the like.

2. Description of the Related Art As a direct-current power generation system used in electric railcars, series hybrid vehicles, and the like, there is known a configuration that includes a generator driven by an internal combustion engine such as an engine, and a rectifier that converts the alternating-current output of the generator to direct current. As an example of a DC power generation system, Patent Literature 1 discloses a configuration using a permanent magnet synchronous generator as a power generator.

JP-A-11-234992

When a direct-current power generation system is to be used in an electric railcar or the like, there are restrictions on the installation space in the vehicle, and so there is a demand for miniaturization and high output of the entire system. Permanent magnet synchronous generators are more efficient and smaller than induction generators. Therefore, by combining a permanent magnet synchronous generator with a full-wave rectifier consisting of a simple diode configuration, it may be possible to realize a highly efficient and compact DC power generation system at low cost.

However, the power generation system disclosed in Patent Document 1 uses a permanent magnet synchronous generator with a special structure to which an excitation winding is added, and it is difficult to reduce the cost. In addition, since the excitation winding is not energized until the full-wave rectifier operates, it is practically impossible to operate at a voltage higher than the open-circuit voltage of the permanent magnet synchronous generator, and it is not possible to increase the size and output of the generator. Therefore, the technology disclosed in Patent Document 1 cannot be adopted.

On the other hand, a normal permanent magnet synchronous generator, which does not have a special structure as disclosed in Patent Document 1, has a characteristic that the magnetic flux generated by the permanent magnet is determined. An output voltage higher than the induced voltage cannot be obtained. Therefore, it is conceivable to combine a permanent magnet synchronous generator with a PWM converter to obtain a large output, but the PWM converter is far more expensive than a full-wave rectifier and requires a large installation space.

The present invention has been made in view of the above circumstances, and its object is to reduce the size and increase the output of a DC power generation system that combines a permanent magnet synchronous generator and a full-wave rectifier. It is to provide technology that can

A first invention for solving the above problems is
a permanent magnet synchronous generator;
a rectifier for full-wave rectifying the alternating current output from the permanent magnet synchronous generator to direct current;
a smoothing capacitor provided in the DC output stage of the rectifier;
a capacitor circuit unit having a capacitor inserted in each phase of an AC line connecting the permanent magnet synchronous generator and the rectifier;
A DC power generation system comprising

According to the first invention, by inserting a capacitor in each phase of the AC line connecting the permanent magnet synchronous generator and the rectifier, the operating point of the permanent magnet synchronous generator can be changed. It is possible to operate with a voltage higher than the induced voltage. As a result, it is possible to reduce the size and increase the output of the DC power generation system. Also, the voltage of the smoothing capacitor becomes the output voltage of the system, and the DC power generation system can be operated as a DC voltage source.

A second invention is based on the first invention,
The permanent magnet synchronous generator has no saliency,
It is a DC power generation system.

According to the second invention, in a permanent magnet synchronous generator having no saliency, the change in inductance due to the current phase angle can be ignored, which facilitates the design of the DC power generation system.

A third invention is the first or second invention,
The permanent magnet synchronous generator is controlled to have a constant rotational speed,
It is a DC power generation system.

According to the third invention, since the rotation speed of the permanent magnet synchronous generator is controlled to be constant, it is possible to operate the permanent magnet synchronous generator with high efficiency. Further, since the power source for rotating the rotor of the permanent magnet synchronous generator also has a constant rotational speed, it is possible to operate the power source with high efficiency.

A fourth invention is, in any one of the first to third inventions,
The permanent magnet synchronous generator is operated and controlled at a rotational speed corresponding to the resonance frequency of an LC circuit composed of the reactance of the permanent magnet synchronous generator and the capacitor,
It is a DC power generation system.

According to the fourth invention, when the permanent magnet synchronous generator is operating at such a rotational speed that the reactance of the permanent magnet synchronous generator and the capacitor of the capacitor circuit form an LC resonance circuit, the rectifier The voltage applied to the AC side becomes equal to the induced voltage of the permanent magnet synchronous generator. As a result, the permanent magnet synchronous generator can be operated at a voltage equal to or higher than the induced voltage, and a highly efficient DC power generation system can be obtained.

The fifth invention is
A DC power generation system according to any one of the first to fourth inventions;
an internal combustion engine that drives the rotor of the permanent magnet synchronous generator;
a transformer connected between the capacitor circuit section and the rectifier in the AC line and outputting the transformed AC to the outside;
with
supplying the DC output of the rectifier as power for the main power supply of the railway vehicle;
Supplying the external output of the transformer as power for the auxiliary power supply of the railway vehicle;
It is a power supply system for railway vehicles.

According to the fifth invention, since the DC power generation system operates as a DC voltage source, the DC output of the rectifier is supplied as power for the main power supply of the railway vehicle, and the external output of the transformer is used as power for the auxiliary power supply of the railway vehicle. can be supplied as In this case, since an auxiliary power supply inverter is not required, it is possible to realize a power supply system for railway vehicles that is compact and low in cost.

The block diagram of a DC power generation system. A current vector diagram of a permanent magnet synchronous generator. Equivalent circuit of a permanent magnet synchronous generator. Equivalent circuit of DC power generation system. A current vector diagram of a DC power generation system. The current vector diagram at the time of resonance of a DC power generation system. Parameter values used in the simulation. A graph that is a simulation result. A graph that is a simulation result. A graph that is a simulation result. A graph that is a simulation result. A graph that is a simulation result. A graph that is a simulation result. A configuration example of a power supply system for railway vehicles.

An example of a preferred embodiment of the present invention will be described below with reference to the drawings. In addition, the present invention is not limited by the embodiments described below, and the forms to which the present invention can be applied are not limited to the following embodiments. Also, in the description of the drawings, the same reference numerals are given to the same elements.

[Constitution]
FIG. 1 is a configuration example of a DC power generation system 1 according to this embodiment. The DC power generation system 1 of the present embodiment is assumed to be used for an electric railroad car, and as shown in FIG. , and a smoothing capacitor 9 .

The permanent magnet synchronous generator 3 is driven by power supplied from an internal combustion engine 10 such as an engine to generate three-phase AC power. Further, in this embodiment, the permanent magnet synchronous generator 3 is a so-called cylindrical machine that does not have saliency. The capacitor circuit unit 5 has a capacitor inserted in each phase of a three-phase AC line connecting the permanent magnet synchronous generator 3 and the full-wave rectifier 7 . The full-wave rectifier 7 is, for example, a three-phase bridge rectifier using diodes, and performs full-wave rectification of the three-phase AC power output from the permanent magnet synchronous generator 3 to convert it into DC power.

A smoothing capacitor 9 is provided at the DC output stage (DC side) of the full-wave rectifier 7 . The smoothing capacitor 9 is provided to absorb abrupt changes in the DC side current due to the rectifying operation of the full-wave rectifier 7 and operate the DC power generation system 1 as a substantially constant voltage DC power supply. It is assumed that the DC power generation system 1 of the present embodiment is used in an electric railcar, and that a current source such as an inverter that supplies electric power to a traction motor is connected as a load. When the smoothing capacitor 9 is not provided and the inverter does not have a filter capacitor, or when the smoothing capacitor 9 is not provided and a filter capacitor and a filter reactor are connected to the DC side of the inverter and the filter reactor is connected to the full-wave rectifier 7 In this case, the reactance of the permanent magnet synchronous generator 3 will be connected in series with the inductive load (main motor or filter reactor), and there is a possibility that a surge voltage will occur with the rectification operation of the full-wave rectifier 7. be. In order to prevent this, a smoothing capacitor 9 is provided in the DC output stage of the full-wave rectifier 7 to absorb sudden changes in the DC side current when the output current of the permanent magnet synchronous generator 3 is rectified, thereby The voltage on the DC side of the rectifier 7 is kept constant.

式（１）において、「ω」は永久磁石同期発電機３の角周波数（所定の回転速度に相当）、「Ｌ_ｑ」は永久磁石同期発電機３のｑ軸インダクタンスである。 In the DC power generation system 1, the permanent magnet synchronous generator 3 is controlled to operate at a rotational speed corresponding to the resonance frequency of the LC circuit composed of the reactance of the permanent magnet synchronous generator 3 and the capacitor of the capacitor circuit section 5. be. Operation control is performed by the internal combustion engine 10 and a control device (not shown) that controls it. The capacitance (capacity) C of the capacitor of the capacitor circuit section 5 is the reactance of the permanent magnet synchronous generator 3 and the capacitor of the capacitor circuit section 5 when the permanent magnet synchronous generator 3 is controlled to operate at a predetermined rotational speed. is set to a value given by the following equation (1) so that the LC circuit formed by and forms an LC resonant circuit.

In equation (1), “ω” is the angular frequency (corresponding to a predetermined rotational speed) of the permanent magnet synchronous generator 3 and “L _q ” is the q-axis inductance of the permanent magnet synchronous generator 3 .

The voltage on the AC side of the full-wave rectifier 7 when the operation is controlled at a predetermined rotational speed is equal to the induced voltage (open voltage) of the permanent magnet synchronous generator 3 when there is no load, regardless of the magnitude of the load current. be equal. Further, in the DC power generation system 1 of the present embodiment, the permanent magnet synchronous generator 3 can be operated at a voltage higher than the induced voltage. A capacitor circuit section 5 is provided between the permanent magnet synchronous generator 3 and the full-wave rectifier 7, and the capacitor of the capacitor circuit section 5 and the reactance of the permanent magnet synchronous generator 3 form an LC resonance circuit. This is due to the fact that it is configured to The reason is explained below.

[analysis]
First, the characteristics of the permanent magnet synchronous generator 3 will be described. The basic characteristics of the permanent magnet synchronous generator 3 are expressed by the following equations (2) to (5) using a dq axis model based on the two reaction method. For the sake of simplicity, losses such as armature winding resistance are ignored. Voltage, current, and inductance are all values per phase.

In the above formulas (2) to (5), “T” is the torque, “m” is the number of phases, “p” is the number of pole pairs of the permanent magnet, “φ _α ” is the magnetic flux linkage of the armature by the permanent magnet, “I _d ” is d-axis current (d-axis component of armature current), “I _q ” is q-axis current, “L _d ” is d-axis inductance, “L _q ” is q-axis inductance, “P” is power, and “ E (=ωφ _α )” is the voltage induced by the permanent magnet, “X _d ” (=ωL _d ) is the d-axis reactance, “X _q ” (=ωL _q ) is the q-axis reactance, and “V _d ” is the d-axis voltage. , “V _q ” is the q-axis voltage, and “δ” is the voltage load angle.

FIG. 2 is a current vector diagram of the permanent magnet synchronous generator 3 corresponding to this characteristic model. Since the permanent magnet synchronous generator 3 generally performs field-weakening control in order to effectively utilize the reluctance torque, the _d -axis current Id is given a negative value in the current vector diagram of FIG.

FIG. 3 is an equivalent circuit of the permanent magnet synchronous generator 3. As shown in FIG. This equivalent circuit is an equivalent circuit per phase based on the characteristic model expressed by equations (2) to (5). In general, an equivalent circuit of a rotating machine such as the permanent magnet synchronous generator 3 is represented by a combination of circuit elements such as resistance representing active power and reactance representing reactive power. FIG. 3 shows an equivalent circuit with series impedance (=R _S +jX _S ) of the permanent magnet synchronous generator 3 . “R _S ” is a resistive element representing active power due to reluctance torque, and “X _S ” is the reactance of the permanent magnet synchronous generator 3 . The following equations (6) to (9) show the relationship between the circuit elements in this equivalent circuit and the device constants of the characteristic model expressed by equations (2) to (5).

Next, the operation of the DC power generation system 1 based on the characteristics of the permanent magnet synchronous generator 3 described above will be analyzed. FIG. 4 is a diagram showing an equivalent circuit per phase of the DC power generation system 1. As shown in FIG. The equivalent circuit of the permanent magnet synchronous generator 3 shown in FIG. 3 is also an equivalent circuit per phase. Also, the capacitor circuit section 5 is a circuit in which a capacitor is inserted in each phase of the permanent magnet synchronous generator 3 . Therefore, by connecting a capacitor for one phase (capacitance C) in series with the equivalent circuit of the permanent magnet synchronous generator 3 shown in FIG. can be expressed as shown. Further, the full-wave rectifier 7 and the load beyond it are expressed as variable resistors (conductance B _L ) whose resistance value changes according to the operating state. This is because the full-wave rectifier 7 operates with a power factor of approximately 100%.

In the equivalent circuit of the DC power generation system 1 shown in FIG. 4, all circuit elements are connected in series, and currents (current vectors I) flowing through the circuit elements are equal. Circuit elements other than the voltage source (voltage vector E) are classified into resistors (conductances R _S and B _L ) that generate active power, and capacitors (capacitance C) and reactors (reactance X _S ) that generate reactive power. be done. Therefore, when a certain current (current vector I) flows, the sum of the voltage generated by the capacitor (capacitance C) and reactor (reactance X _S ) and the reactive voltage component of the voltage source (voltage vector E) becomes zero. Because of the need, the voltage load angle δ, which is the phase difference between the current source (current vector I _m ) and the voltage (voltage vector V), is determined.

Then, the conductance B _L of the variable resistor is determined so that the sum of the effective voltage component of the voltage source E at the voltage load angle δ and the voltage generated by the resistors (conductance R _S , B _L ) becomes zero. Then, the operating state of the DC power generation system 1 at that current (current vector I) is determined.

When the DC power generation system 1 is applied as a power supply source to a traction motor of a vehicle system, an inverter is connected as a load to the DC side of the full-wave rectifier 7, and the load current is determined as the vehicle runs. The operating state is determined accordingly. Therefore, the above analysis procedure is close to this application form.

FIG. 5 is a current vector diagram of the DC power generation system 1 when the permanent magnet synchronous generator 3 is operating to generate power. In FIG. 5, the permanent magnet synchronous generator 3 is cylindrical with no saliency, and the change in inductance due to the current phase angle β can be ignored, so the resistor (conductance R _S ) can be omitted. can. As shown in the current vector diagram shown in FIG. 5, the _q -axis current Iq is negative when the permanent magnet synchronous generator 3 is generating power. Further, since the permanent magnet synchronous generator 3 is generally subjected to field weakening control, the _d -axis current Id is made negative. Also, the voltage V _L applied to the variable resistor (conductance B _L ) that serves as the load is orthogonal to the voltage applied to the reactor (reactance X _S ) and the capacitor (capacitance C).

Therefore, in order to operate the permanent magnet synchronous generator 3 with the voltage vector V, first, the voltage vector E is subtracted from the voltage vector V to obtain the voltage vector _XSI applied to the reactor (reactance _Xs ). . Then, the voltage vector CI applied to the capacitor (capacitance C) is added to the voltage vector V to obtain the voltage vector V _L applied to the variable resistor (conductance B _L ). Then, the value of the capacitance (capacitance) C of the capacitor should be determined so that the voltage vector _VL is orthogonal to the current vector I. By doing so, the permanent magnet synchronous generator 3 can be operated to generate power at an arbitrary operating point.

In the equivalent circuit of the DC power generation system 1 shown in FIG. 4, a reactor (reactance X _S ) and a capacitor (capacitance C) form an LC series circuit. This LC series circuit can be formed as a resonant circuit by selecting the capacitance C of the capacitor so that the LC series circuit becomes a resonant circuit at the rotational speed during power generation operation. At resonance, the voltage applied to the capacitor (capacitance C) and the voltage applied to the reactor (reactance X _S ) are equal in magnitude and opposite in phase. A current vector diagram at the time of resonance is as shown in FIG.

FIG. 6 is a current vector diagram of the DC power generation system 1 during resonance. At resonance, the voltage V _L applied to the variable resistor (conductance B _L ) becomes equal to the induced voltage E of the permanent magnet synchronous generator 3 regardless of the magnitude of the load current (current vector I). Then, the permanent magnet synchronous generator 3 can be operated at a voltage V higher than the induced voltage E. The voltage V _L applied to the variable resistor (conductance B _L ) is the voltage applied to the AC side of the full-wave rectifier 7, and is provided on the DC side (DC output stage) of the full-wave rectifier 7. The voltage of the smoothing capacitor 9 becomes a DC voltage corresponding to the voltage V _L (=the induced voltage E of the permanent magnet synchronous generator 3). Therefore, the DC power generation system 1 operates as a DC voltage source.

At this time, only the _q -axis current Iq is flowing through the permanent magnet synchronous generator 3 . Generally, in order to maximize the output of the permanent magnet synchronous generator 3 under the limit of winding temperature rise, MTPA
(Max Torque Per Ampere: maximum torque/current) It is desirable to control the operation with the current vector of control. The current vector diagram shown in FIG. 6 is a state close to the operating state under MTPA control, and can be said to be a desirable operating point from the viewpoint of increasing the output.

Therefore, at the operating point under load, the capacitance C of the capacitor is increased so that the LC series circuit composed of the capacitor (capacitance) C and the reactor (reactance X _S ) of the permanent magnet synchronous generator 3 forms a resonant circuit. It is determined as shown in formula (1). At the time of resonance, it _is the _q -axis current _Iq that generates the induced voltage _XSI due to the current. reactor.

[simulation result]
Next, simulation results of the DC power generation system 1 are shown. The simulation was performed assuming that the DC power generation system 1 is used in an electric railcar. In other words, this is the case where a railroad diesel engine is directly connected to the permanent magnet synchronous generator 3 as the internal combustion engine 10 . In the simulation, a predetermined rotational speed was input to the shaft of the permanent magnet synchronous generator 3 instead of the diesel engine. A smoothing capacitor 9 is connected to the direct current side of the full-wave rectifier 7, and a constant current source assuming an inverter-driven motor or the like is arranged as a load.

FIG. 7 shows device constants of the permanent magnet synchronous generator 3 and design values of the DC power generation system 1 as parameter values used in the simulation. In the simulation, the capacity of the capacitor (resonance capacitor) of the capacitor circuit section 5 was designed so that the resonance frequency was obtained at the engine speed of 2100 rpm, which provides the maximum output of the engine. In addition, since the open-circuit voltage of the permanent magnet synchronous generator 3 at the engine speed of "2100 rpm" is "622 V" at the peak value between the terminals, it is assumed that the DC voltage will be about "600 V". The DC current was set to "300 A" so as to be approximately "180 kW". In addition, the engine speed was accelerated from 0 rpm to 2100 rpm for the first 4 seconds (from 0 to 4 seconds) when the load current was zero, and then the engine speed was kept constant. . Then, the load current was linearly increased from "0 A" to "300 A" in a period of "5 seconds to 9 seconds" and then kept constant.

8 to 13 are graphs showing simulation results. 8 and 9 are graphs for the last 0.1 seconds of the simulation (from 9.9 seconds to 10.0 seconds), and FIGS. up to).

FIG. 8 shows the voltage V and current I of the permanent magnet synchronous generator 3 and the input voltage (voltage on the AC side) of the full-wave rectifier 7, with the horizontal axis representing time. According to FIG. 8, the current I of the permanent magnet synchronous generator 3 and the input voltage (voltage on the AC side) of the full-wave rectifier 7 are in opposite phases. The input current of the full-wave rectifier 7 is equal to the current I of the permanent magnet synchronous generator 3. That is, even if the capacitor circuit unit 5 is provided between the permanent magnet synchronous generator 3 and the full-wave rectifier 7, AC power with a power factor of approximately 100% is input to the full-wave rectifier 7 as in the case of not providing the capacitor circuit unit 5. It was confirmed that It should be noted that the output voltage V and the output current I of the permanent magnet synchronous generator 3 are largely out of phase and the power factor is low. This is due to the large armature reaction.

9 shows the voltage of the smoothing capacitor 9 (which is the output voltage of the DC power generation system 1), the load current, the rotation speed of the permanent magnet synchronous generator 3, and the time of the permanent magnet synchronous generator 3, with the horizontal axis representing time. output torque (permanent magnet synchronous machine torque). The output torque (permanent magnet synchronous machine torque) of the permanent magnet synchronous generator 3 is shown as a negative value. The input torque of the permanent magnet synchronous generator 3 is a positive value and its average value is "770 Nm", the average value of the voltage of the smoothing capacitor 9 is "534 V", and the power generated by the permanent magnet synchronous generator 3 is "approximately 160 kW. ”. As shown in FIG. 9, due to the operation of the full-wave rectifier 7, harmonic components are added to the voltage, resulting in torque pulsation. It can also be seen that the voltage of the smoothing capacitor 9 also has fine pulsations of the same frequency.

FIG. 10 shows the effective value of the voltage V of the permanent magnet synchronous generator 3 with the horizontal axis representing time. FIG. 11 shows the effective value of the input voltage (voltage on the AC side) of the full-wave rectifier 7, with the horizontal axis representing time. FIG. 12 shows the effective value of the current I of the permanent magnet synchronous generator 3 with the horizontal axis representing time. FIG. 13 plots time on the horizontal axis, the load current, the voltage of the smoothing capacitor 9, the effective value of the input voltage (AC side voltage) of the full-wave rectifier 7, the torque of the permanent magnet synchronous generator 3, and the permanent and the rotational speed of the magnetosynchronous generator 3. FIG.

10 to 13, when there is no load (period from 0 seconds to 4 seconds), as the rotation speed of the permanent magnet synchronous generator 3 increases, the voltage of the permanent magnet synchronous generator 3 and the full-wave rectifier 7 input voltage and the voltage of the smoothing capacitor 9 increase. After the rotation speed of the permanent magnet synchronous generator 3 reaches "2100 rpm" and becomes constant, when the load current is increased (duration from 5 seconds to 10 seconds), the voltage of the permanent magnet synchronous generator 3 becomes Although increasing, the input voltage (AC side voltage) of the full-wave rectifier 7 is kept substantially constant. In other words, the input voltage of the full-wave rectifier 7 is constant regardless of the load current. When the load current starts to flow (5 seconds), the voltage of the smoothing capacitor 9 drops due to the operation of the full-wave rectifier 7, but after that (5 seconds to 10 seconds), the load current Even if it is increased, the voltage remains constant.

[Application example]
The DC power generation system 1 of the present embodiment can be applied to, for example, a railroad vehicle power supply system that is mounted on a railroad vehicle and supplies electric power to a main power source and an auxiliary power source of the railroad vehicle. FIG. 14 is a configuration example of a power supply system 100 for railway vehicles. As shown in FIG. 14, a railroad vehicle power supply system 100 includes a DC power generation system 1, an internal combustion engine 10 that drives the rotor of a permanent magnet synchronous generator 3, and a capacitor circuit section in an AC line of the DC power generation system 1. 5 and a transformer 11 connected between the full wave rectifier 7 . The transformer 11 transforms the voltage on the AC side of the full-wave rectifier 7 and outputs the transformed AC voltage to the outside. The railroad vehicle power supply system 100 supplies the DC output of the full-wave rectifier 7 as the power of the main power supply that is the power source of the traction motor of the railroad vehicle, and the external output (AC output) of the transformer 11 as the power supply of the railroad vehicle. Supplied as power for the auxiliary power supply that powers the auxiliary equipment. Conventionally, an SIV (Static Inverter) was required for the power source of the accessory, but the transformer 11 replaces this. As a result, the power supply system 100 for railroad vehicles can be provided with reduced costs and a reduced installation space. It is more preferable to design the operating frequency of the permanent magnet synchronous generator 3 during resonance to be the commercial frequency (50/60 Hz), because it can match the frequency of the auxiliary power supply.

By designing the DC power generation system 100 so that the voltage of the AC line of the DC power generation system 100 (the voltage on the AC side of the full-wave rectifier 7) is the voltage for the auxiliary equipment, the auxiliary equipment can be connected directly to this AC line. can be connected to eliminate the transformer 11. In this case, since the voltage on the AC side of the full-wave rectifier 7 has a rectangular wave shape (see "rectifier input voltage" in FIG. 8), it is preferable to connect the auxiliary machine via a filter circuit.

[Effect]
Thus, according to the DC power generation system 1 of the present embodiment, by inserting a capacitor in each phase of the AC line connecting the permanent magnet synchronous generator 3 and the full-wave rectifier 7, the permanent magnet synchronous generator 3 operates. The point can be changed, and the permanent magnet synchronous generator 3 can be operated at a voltage higher than the induced voltage. Moreover, the voltage of the smoothing capacitor 9 becomes the output voltage of the DC power generation system 1, and the DC power generation system 1 can be operated as a DC voltage source. Further, by controlling the operation of the permanent magnet synchronous generator 3 at a rotation speed corresponding to the resonance frequency of the LC circuit composed of the reactance of the permanent magnet synchronous generator 3 and the capacitor of the capacitor circuit unit 5, the full wave rectifier 7 becomes equal to the induced voltage of the permanent magnet synchronous generator 3, and the output DC voltage can be kept constant even if the load current changes. As a result, it is possible to reduce the size and increase the output of the DC power generation system 1 .

In addition, since the rotational speed of the permanent magnet synchronous generator 3 can be controlled to be constant, the permanent magnet synchronous generator 3 can be operated with high efficiency, and the rotor of the permanent magnet synchronous generator 3 can be rotated. Since the power source (internal combustion engine 10) that drives the engine can also be operated at a constant rotational speed, it is possible to operate the power source with high efficiency. That is, it can be said that it is possible to design the DC power generation system 1 according to the fuel efficiency of the internal combustion engine 10 . Alternatively, it is also possible to adopt the internal combustion engine 10 whose speed corresponding to the rotation speed of the permanent magnet synchronous generator 3 has a predetermined fuel efficiency performance. As a result, it is possible to improve the fuel efficiency of the system as a whole including the internal combustion engine 10 and the DC power generation system 1 .

It goes without saying that the embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be changed as appropriate without departing from the scope of the present invention.

In the present embodiment described above, the case where the DC power generation system 1 is applied as a power supply source to the main motor of a railway vehicle has been mainly described. However, the form to which the DC power generation system 1 can be applied is not limited to the embodiment described above. For example, the direct current output stage (direct current side) of the full-wave rectifier 7 may be connected to the supply line of the auxiliary power supply of the railway vehicle, and the DC power generation system 1 may be applied as a power supply source for the auxiliary power supply of the railway vehicle. good. In addition, the DC power generation system may be applied as a power supply source not only for railway vehicles but also other large vehicles, ships, etc., and as a power supply source for industrial use.

DESCRIPTION OF SYMBOLS 1... DC power generation system 3... Permanent-magnet synchronous generator 5... Capacitor circuit part 7... Full wave rectifier 9... Smoothing capacitor 11... Transformer 10... Internal combustion engine

Claims (5)

a permanent magnet synchronous generator;
a rectifier for full-wave rectifying the alternating current output from the permanent magnet synchronous generator to direct current;
a smoothing capacitor provided in the DC output stage of the rectifier;
a capacitor circuit unit having a capacitor inserted in each phase of an AC line connecting the permanent magnet synchronous generator and the rectifier;
DC power generation system. The permanent magnet synchronous generator has no saliency,
The DC power generation system according to claim 1. The permanent magnet synchronous generator is controlled to have a constant rotational speed,
The DC power generation system according to claim 1 or 2. The permanent magnet synchronous generator is operated and controlled at a rotational speed corresponding to the resonance frequency of an LC circuit composed of the reactance of the permanent magnet synchronous generator and the capacitor,
The DC power generation system according to any one of claims 1 to 3. A DC power generation system according to any one of claims 1 to 4,
an internal combustion engine that drives the rotor of the permanent magnet synchronous generator;
a transformer connected between the capacitor circuit section and the rectifier in the AC line and outputting the transformed AC to the outside;
with
supplying the DC output of the rectifier as power for the main power supply of the railway vehicle;
Supplying the external output of the transformer as power for the auxiliary power supply of the railway vehicle;
Power supply system for railway vehicles.

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