CA3024347A1 - Traction power supply system for high speed train and its on-board power storage and discharge system - Google Patents

Abstract

A traction power supply system for high-speed rail, comprising: an internal power supply device. The internal power supply device comprises an internal locomotive power supply and auxiliary power supply circuit, and an on-board power storage and discharge circuit. The internal locomotive power supply and auxiliary power supply circuit and the on-board power storage and discharge circuit form a composite circuit. Two-way single-phase a and ß circuits from a traction power supply grid (A, B, C) traction transformer (S) secondary side are conducted to an internal power supply system by means of dual-phase pantographs T1 and T2. When one of the dual-phase pantographs T1 and T2 is raised, the other must be dropped. Alternatively, both dual-phase pantographs can be dropped. Wherein the single-phase a current is always connected to the internal locomotive power supply and auxiliary power supply circuit. The single-phase ß current is always connected to the on-board power storage and discharge circuit. The internal locomotive power supply and auxiliary power supply circuit and the on-board power storage and discharge circuit are mutually independent and insulated from each other. The composite circuit of the traction power supply and a basic circuit (CRH1) share a set of an internal auxiliary power supply system and a set of an internal locomotive power supply system. The invention can simplify a structure of a circuit, ensure zero incidence of negative-sequence current throughout a transportation process, and does not require setup of a power grid and a power grid supporting structure in a number of areas.

Description

TRACTION POWER SUPPLY SYSTEM FOR HIGH SPEED TRAIN AND
ITS ON-BOARD POWER STORAGE AND DISCHARGE SYSTEM
Technical Field The invention relates to a traction power supply system for a high speed train, which is a power source for ensuring safe, stable and efficient operation of the high speed train, and which is responsible for stable, continuous and reliable power supply to high speed EMU (Electric Multiple Units) , and which is one of the important infrastructures of electrified railways. The invention especially relates to an onboard energy storage and discharge system of a traction power supply system for a high speed train, with the aim of balancing the negative sequence current of a dedicated power grid and saving part of the power grid support structure.
Background In terms of the existing high-voltage transmission system for high speed train, three-phase alternating current of 3.15 - 20KV outputted from a power plant is boosted by step-up/step-down transformer TM1 to 35-500KV high-voltage current and then inputted to a local substation DB, or inputted to the local substation DB through the step-up/step-down transformer TM1 by three-phase high-voltage power grid; the local substation DB outputs three-phase alternating current of 110KV or 220KV (220KV
for high-speed EMU) to a primary side of a traction transformer S; and a secondary side of the traction transformer S outputs a single-phase alternating current of 27.5KV (rated voltage 25KV), which is connected to a traction power supply line T. The single-phase alternating current from the traction power supply line T is connected to the locomotive power supply and auxiliary power supply inside the EMU via a single-phase pantograph and a single-phase main circuit breaker, to form an external single-phase traction power supply system, as shown in FIG. 8. Due to single-phase power supplying, the traction power supply grid has the advantages of simple structure, low construction cost, convenient operation and maintenance, and is thus beneficial to the railway power sectors.
However, the single-phase power supplying will cause an imbalance in the three-phase high-voltage power supply, causing a negative sequence current. When the negative sequence current passes through the transmission lines, the negative sequence power does not work, which will affect the power quality of the power grid, reduce the power factor, increase the energy loss of the power grid, reduce the transmission capacity of the power grid, and increase the difficulty of protection. In order to solve the adverse effects of the negative sequence current, it is necessary to provide a phase separation insulator or a disconnection switch in the neutral section, which will increase the design and construction trouble of the external traction power supply system. To this end, the inventors filed the Chinese patents for invention No. 201410182358.0 and No.
201410239724.1 for solving the problem of negative sequence current. These two patent applications can solve the problem of no negative sequence in the whole process. However, the electrified railway power grid must be equipped with complex mechanical support structures to support the full loads of the traction power supply grid, and ensure the stability, reliability and safety of the power grid, which also must be solved. To this end, the applicant of the present invention filed the Chinese patent application for invention No.
201410409606.0, and the main contents of this patent application are repeated below: as shown in FIG. 7 and FIG. 6, the external power supply system is, in the upper part of a column of anchoring legs 22 of the railway single-row line, provided with wrist arm positioning devices 33; two mutually parallel messenger wires 44 are fixedly arranged on each of the wrist arm positioning devices 33; each messenger wire 44 is fixedly connected to one end of a dropper 55, and the other end of the dropper is in connection with the power supply contact wire. For single-line dual-phase power supply, A, B, C
three-phase high voltage 110KV (220KV for high speed train) is inputted into the primary side of the traction transformer S, the secondary side of the traction transformer S
outputs single-phase circuit of a and /3 two-phase 27.5KV (rated voltage 25KV), and the a and fl two-way single-phase circuits are respectively connected to the two single-phase contact wires 111. The two messenger wires 44, the two droppers 55, and the two power supply contact wires 111 respectively are parallel to each other, and are insulated from each other by insulators M1 and M2, excluding the possibility of short circuit. The two single-phase contact wires 111 are contact connected to sliding contactors a' and g provided at the top of the dual-phase pantographs Ti and T2, respectively. The main circuit breaker switch of the EMU is inputted through left and right arms La and Ra of the dual-phase pantographs T1 and T2 by the sliding contactors a' and fl', the main circuit breaker switch connects disconnecting switches K 1 a and Kit? or K2, and K211, so as to power the inside of the EMU. For the upstream and downstream double-track railway, the inner side of the double-track railway is only provided with one row of anchoring legs 22, and the wrist arm positioning devices 33 are symmetrically disposed on the upper portion of the anchoring legs 22, which is beneficial to save manpower and material resources and

2 to increase stability of the anchoring legs 22.
In the Chinese patent application for invention No. 201410409606.0, as shown in FIG.
9, the onboard power supply line structure of the 8-car EMU is illustrated, wherein the single-phase a and single-phase/3 two-way power supply lines are transmitted to the power supply system inside the EMU through the left arm La and the right arm Ra of the two-phase pantographs by the contactors a' and p, and the single-phase circuit a and the single-phase circuit /0 are connected to the two-phase disconnecting switches Kla and Klfi or K2õ and K2fi. One of the dual-phase pantographs T1 and T2 is raised, and the other must be dropped. When T1 is raised and T2 is lowered, the two-phase disconnecting switch K 1 a makes the single-phase circuit a connected to a basic unit TUB1 of the traction power-supply and auxiliary power-supply loads of the EMU, and the two-phase disconnecting switch K lfi makes the fl single-phase circuit connected to a basic unit TUB2 of the onboard battery. When T2 is raised and T1 is lowered, the two-phase disconnecting switch K2fi makes the single-phase circuit /3 connected to the basic unit TUB1 of the traction power-supply and auxiliary power-supply loads of the EMU, and the two-phase disconnecting switch K2, makes the a single-phase circuit connected to the basic unit TUB2 of the onboard battery. TUB1 and TUB2 are independent of each other and alternately in contact with each other, increasing the symmetry of electricity taking by the three-phase high voltage grids A, B and C. Therefore, the a single-phase and ,8 single-phase circuit two-way electric wires at the traction power supply section do not have a neutral-section passing neutral section, and the A, B, and C three-phase dedicated high-voltage power grids do not give rise to negative sequence current.
Although this invention application describes the contents of no negative sequence during whole process and no power grid intermittently, the circuit structure and connection mode of the onboard battery are not specifically described. It can be seen from the above that the design for the onboard power storage and discharge circuit structure and its components is an imperative problem to be solved by the present invention.
Contents of the Invention In view of the prior art, the present invention proposes a traction power supply system for a high speed train, comprising an onboard power supply device, the onboard power supply device comprising an onboard driving power supply and auxiliary power supply circuit, and an onboard power storage and discharge circuit, wherein the onboard

3 driving power supply and auxiliary power supply circuit and the onboard power storage and discharge circuit constitute a composite circuit, wherein two-way single-phase electric circuits a and fl from a secondary side of a traction transformer of a traction power supply grid are conducted to theonboard power supply device by means of dual-phase pantographs Ti and T2, when one of the dual-phase pantographs T1 and T2 is raised, another of the dual-phase pantographs Ti and T2 must be lowered, or both the dual-phase pantographs Ti and T2 can be lowered, wherein the single-phase electric circuit a is always connected to the onboard driving power supply and auxiliary power supply circuit, the single-phase electric circuit fl is always connected to the onboard power storage and discharge circuit, and the onboard driving power supply and auxiliary power supply circuit and the onboard power storage and discharge circuit are independent of each other and insulated from each other.
Preferably, the onboard power storage and discharge circuit includes a combination of supercapacitors and high capacity battery.
Preferably, the onboard driving power supply and auxiliary power supply circuit includes an onboard basic circuit, wherein the onboard basic circuit is divided into two ways by direct current outputted from a main converter: a first way is directly connected to an auxiliary power supply system via an auxiliary converter, while a second way feeds a traction motor through a traction converter so as to be connected to a driving power supply system, wherein a lead-out connecting line having a terminal A is added between the main converter and the auxiliary converter; a bidirectional switch K3 is added between the main converter and the traction converter, and when a C terminal of B-C of the bidirectional switch K3 is turned on, a B-B wire of the bidirectional switch K3 is turned off.
Preferably, when the motor car comes to section LI, the single phase electric circuit a is transmitted to the dual-phase pantograph T1 from the traction power supply grid and inputted into the car through a two-phase cutout switch Kla , or when the motor car comes to the next section Li, the single-phase electric circuit a is transmitted to the dual-phase pantograph T2 from the traction power supply grid and inputted into the car through a two-phase cutout switch K2,, the single-phase electric circuit a feeding the onboard driving power supply and auxiliary power supply circuit; when the motor car comes to the section LI, the single phase electric circuit fi is transmitted to the dual-phase pantograph Ti from the traction power supply grid and inputted into the car through a two-phase cutout switch KIM, or when the motor car comes to the next section Li, the single-phase electric circuit 16 is transmitted to the dual-phase pantograph T2 from the traction power

4 supply grid and inputted into the car through a two-phase cutout switch K2fi , wherein the single-phase electric circuit /3 is divided into two ways by direct current outputted from the main converter: one way is directly connected through a diode to the terminal A of the connecting line led out from between the main converter and the auxiliary converter of the basic circuit, while an another way is connected from an output end of the onboard power storage and discharge circuit to the terminal C of the bidirectional switch K3 of the basic circuit through the diode, the diode preventing the electrical current energy from flowing back.
Preferably, the main converter of the composite circuit is connected to the terminal A
of the connecting line of the basic circuit via the diode, and the terminal A
in turn is connected to the auxiliary converter of the basic circuit, so that the auxiliary power supply of the composite circuit and the auxiliary power supply of the basic circuit have a common auxiliary power supply system; and the auxiliary converter, a transformer of a filter transformer and a battery of the common auxiliary power supply system have an increased capacity, wherein the battery is a lithium ion battery having a capacity greater than or equal to a sum of the capacity of the battery of the basic circuit and the auxiliary supply power amount required by the motor car to come to section L2.
Preferably, the electrical current outputted from the onboard power storage and discharge circuit is connected to the terminal C of the bidirectional switch K3 of the basic circuit via the diode and enters into the driving power supply system of the basic circuit, at this moment, B-B of the bidirectional switch K3 is turned off, power supplying of the composite circuit and power supplying of the basic circuit have a common power supply system, and the onboard power storage and discharge circuit has a high capacity battery with the increased energy capacity, wherein the rated voltage of the high capacity battery pack is matched with the voltage of a traction inverter, the energy capacity of the high capacity battery pack is greater than or equal to the energy required by the motor car to come to the section L2, and the high capacity battery pack is formed by connecting graphene cells, hydrogen fuel cells and lithium ion cells in parallel and in series.
Preferably, the onboard power storage and discharge circuit is direct current outputted by the single-phase electric circuit fl via the main converter, the negative pole of the direct current is connected to the negative pole of the main circuit of the onboard power storage and discharge circuit, the positive pole of the direct current is inputted into a charging snubber circuit, the charging snubber circuit after being connected in parallel with a short-circuit contactor and a charging current-limiting resistor is coupled in series with the positive pole of the main circuit, wherein when the voltage of the supercapacitor pack is smaller than a lower limit, the short-circuit contactor is turned off to let the charging current-limiting resistor have access to the circuit, thus limiting the instantaneous charging current when supplying the power; and when the voltage of the supercapacitor pack is higher than the lower limit, the signal outputted from a controller pulls in the short-circuit contactor to cut off the charging current-limiting resistor, the supercapacitor pack is bridged between the positive and negative poles of the main circuit, and the electrical current outputted from the charging snubber circuit charges the supercapacitor pack.
Preferably, when the supercapacitor pack is fully charged by the electrical current outputted from the charging snubber circuit, electrical current through a current sensor of the supercapacitor pack is zero, and a signal is outputted to the controller;
a signal output end of the controller inputs the signal into the gate of the bidirectional switch's VT1, and VT1 is switched on; the high capacity battery pack is charged via the current sensor and the bidirectional switch's VT1, and via a freewheeling diode VD2; and the E-pole of the bidirectional switch's VT1 and the E-pole of the VT2 are connected together, only one being in an ON state.
Preferably, when the high capacity battery pack is fully charged with the electrical current, i.e., electrical current through the current sensor of the high capacity battery pack is zero, or when the voltage sensor bridged between the positive and negative poles of the supercapacitor pack is equal to the voltage sensor bridged between the high capacity battery packs, the high capacity battery packs discharge, and at this moment the signal output end of the controller is inputted and the bidirectional switch's VT2 is switched on, and the high capacity battery pack discharges to the main circuit output end through the current sensor and the bidirectional switch's VT2 and the freewheeling diode VDi.
Preferably, the main converter of the main circuit is connected to the C-end of the bidirectional switch K3 of the basic circuit via an uncontrollable diode, turning off the B-B and turning on the B-C of the bidirectional switch K3, and connected to the traction converter of the basic circuit via the B-C, and then the traction motor is supplied with power by the traction converter; the supercapacitor pack acts as an energy buffer of the main circuit to share the instantaneous power burden of the high capacity battery pack, wherein the short-term power fluctuation or instantaneous over-voltage and under-voltage are mainly borne by the supercapacitor pack, and the main part of the load fluctuation for longer time is borne by the high capacity battery pack, an electrolytic capacitor bridged between the positive and negative poles of the main circuit is used as a high frequency filter, and the positive pole of the main circuit is connected to the input end of the driving power supply energy storage and discharge circuit through the output current sensor.
Preferably, the positive pole of the main circuit is connected to the driving power supply system through the output current sensor and the disconnect switch, the voltage sensor is bridged between the positive and negative poles of the main circuit, with its signal output end being connected to the signal input end of the controller;
the voltage sensor of the high capacity battery pack is bridged between both ends of the high capacity battery pack, with its output signal being transmitted to the input end of the controller, the signal output ends of the current sensor of the supercapacitor pack and the current sensor =
of the high capacity battery pack connect to the controller respectively, while the signal output ends of the output current sensor connect to the controller respectively; the signal output ends of the controller are respectively connected to the gates of VT1 or VT2, the output end of the controller is connected to the voltage snubber circuit, and the output end of the controller is connected to the disconnect switch.
The onboard power storage and discharge circuit is the main content of the present invention, hereinafter referred to as the main circuit. The main circuit is centered on the supercapacitor pack and the high capacity battery pack, supplemented by the bidirectional switch, and combined with the signal acquisition and controller. The supercapacitor pack has a high power density and the high capacity battery has the great energy capacity, and their combination can provide energy buffering for the high capacity battery pack and also can give full play to high-power supply capability of the supercapacitor pack.
The bidirectional switch is composed of two power MOSFET tubes or IGBT tubes, and the breakdown voltage thereof can reach 1200V, the maximum saturation current of the collector has exceeded 1500A, and the operating frequency can reach 20kHz. The signal is inputted into the controller by the current sensor and voltage sensor of the supercapacitor pack, the current sensor and voltage sensor of the high capacity battery pack, and the main circuit current sensor; and the control signal outputted from the controller is inputted to the charging buffer, the gate of VT1 and VT2 of the bidirectional switch and the output current sensor, so as to realize the running process of the main circuit.
When the supercapacitor pack completes the charging of the high capacity battery pack, the VII in the main circuit bidirectional switch is turned off, and only the supercapacitor pack continues to participate in the rectification and outputting, forming a hot backup and ensuring the stable voltage of the output end, thus functioning as a partial UPS. The electrical current is transmitted, through the current sensor, to the onboard power storage and discharge circuit output end from the high capacity battery pack via the current sensor of the high capacity battery, thyristor VT2 and the freewheeling diode VD1.
The supercapacitor pack can reach full power output in a short time, so that the instantaneous grid fluctuations are completely stored by the supercapacitor pack, and transmitted to the output end of the onboard power storage and discharge circuit as much as possible through the output current sensor, so as to meet the high power requirements, and also it is possible to bear the transient over-voltage or under-voltage and avoid the instantaneous voltage drop, so that the instantaneous fluctuation current feedback by the traction motor energy is completely stored by the capacitor pack, thereby acting as the peak-cut for the electric energy supply or load fluctuation and taking the role of an energy filter. When the instantaneous high pulse power output is required, the supercapacitor pack can work in the charging state instantaneously, so that the high capacity battery pack can meet the high power requirement, effectively protect the overall safety of the high capacity battery pack, and stabilize the bus voltage to ensure reliability of the outputted electrical energy. This can meet the external power supply requirements of greater energy, while the supercapacitor pack can suppress voltage fluctuations, and the output current sensor is responsible for monitoring the input current. This mode is mainly used for load feedback of electric energy, or transient over-voltage due to the load fluctuation. The output voltage from the output end, and the high-frequency filtering function of the electrolytic capacitor between the positive and negative poles of the main circuit further improve the quality of the direct current, and the direct current from the onboard power storage and discharge circuit output end is transmitted to the inverter via the main circuit disconnect switch, and to the traction motor, thereby completing the entire process of power supplying in the motor car.
The present invention has the following advantageous effects:
1. The invention utilizes the mature and reliable known technology of the out-car current supply and in-car current supply as much as possible, which can save a lot of manpower, material resources and financial resources.
2. The design of the present invention is based on the composite circuit consisting essentially of a basic circuit and an onboard power storage and discharge circuit. The basic circuit is based on the CRHl line, in which the connection mode of the lines and components are the same as these of the basic circuit, which saves a lot of circuit design and component purchase costs.

3. The basic circuit and the composite circuit of the present invention share one set of auxiliary power supply system and one set of driving power supply system, which saves the main energy storage structure.
4. The two-way external alternating current circuits a and )3 of the present invention supplies current to the onboard electricity line and the onboard power storage and discharge line through two-phase power grid. The two-way single-phase circuits a and p are independent of each other and insulated from each other, and have the same electric power consumption. The external circuit a is always connected to the internal circuit a, and the external circuit 13 is always connected to the internal circuit ig .
This ensures that the frequency of the grid is absolutely the same as the frequency of the power line, the phase sequence is the same as the grid, and the phase and the grid are strictly synchronized.

5. The onboard power storage and discharge circuit of the present invention is mainly composed of the supercapacitor packs and high capacity battery packs. The advantage of the supercapacitor pack is that the power density is high, and the high capacity battery pack has the advantage of high energy density, and their coordinated combination is the best way of energy storage.
Description of the Drawings Fig. 1 is an onboard composite circuit diagram in accordance with one embodiment of the present invention;
Fig. 2 is a diagram of an onboard power storage and discharge circuit in accordance with one embodiment of the present invention;
Fig. 3 is a structural diagram of a basic circuit CRH1 according to one embodiment of the present invention;
Fig. 4 is a schematic view showing an arrangement order of 8-car EMU and a pantograph setting position for the existing four different models;
Fig. 5 is a schematic diagram showing the locomotive power supply and auxiliary power supply, and onboard power storage and discharge circuit of the 8-car EMU
according to the present invention;
Fig. 6 is a front view of the external two-phase power supply of the existing electrified railway;
Fig. 7 is a side view of Fig. 6;
Fig. 8 is a schematic diagram of external single-phase power supply of the existing electrified railway; and Fig. 9 shows the onboard power supply line structure of the existing 8-car EMU.
In the Figures: G indicates a generator; TM1 indicates a step-up transformer, indicates a step-down transformer; ABC indicates three-phase high voltage dedicated power grids; S indicates a traction transformer; D indicates the high-speed train; 11 and T2 indicate single-phase pantographs; Ti and T2 indicate dual-phase pantographs; Kr, K22 indicate two-phase cutout switches for the driving and auxiliary power supply of EMU; Klfi and K2fi indicate cutout switches for the onboard power storage and discharge circuit; M indicates a traction motor; and Ra and Rje indicate high current step-down resistors; R indicates railway; and a' and ,6' indicate sliding contactors at the upper ends of the left arm La and the right arm Ra; MI, M2 indicate the insulators between the left arm La and the right arm Ra.
List of reference signs:
1: grounding switch 2: main circuit breaker 3: voltage measuring transformer 4: filter 5: current transformer

6: surge arrester (arrester),

7: main transformer

8: main converter

9: traction converter

10: traction motor

11: auxiliary converter

12: filter transformer

13: charger

14: battery switch

15: battery

16: DC switch 61, 62: uncontrollable diodes 63: charging snubber circuit, short-circuit contactor, charging current-limiting resistor R, 64: controller 65: voltage sensor 66: supercapacitor pack 67: high capacity battery pack 68: voltage sensor of the high capacity battery 69-1: current sensor of the supercapacitor pack 69-2: current sensor of the high capacity battery pack 610: bidirectional switch, 611: electrolysis capacitor 612: main circuit current sensor 613: main circuit disconnect switch.
Embodiments The present invention makes full use of the mature and reliable known technology of the EMU, which can save a lot of manpower, material resources and financial resources.
The main design of the invention is the composite circuit. The composite circuit consists of a basic circuit and an onboard energy storage and discharge circuit.
Embodiments of the present invention will be further described hereinafter in conjunction with the accompanying drawings.
The existing 8-car EMU in China have substantially the same circuit structure, except for the different arrangement order of the cars and the different disposing positions of the pantographs, as shown in Figure 4 (a), Figure 4 (b), Figure 4 (c) and Figure 4 (d). One embodiment of the present invention takes the onboard driving, auxiliary power supply system in the 8-car EMU of CRH1 type as an example, as shown in FIG. 3, and reference numerals in FIG. 3 are different from the sequences of the original CRH1 line structure components, but the corresponding components are exactly the same.
Basic circuit: the existing 8-car EMUs of CR1-I1, CRH2, CRH3 and CRH5 type in China mainly differ from each other by the different arrangement sequences of the motor cars and trailer cars and the different roofs where the pantograph is disposed, and their internal lines and components are basically the same. One embodiment of the present invention is described with the 8-car EMU of CRH1 type as a representative, without losing the generality, as shown in FIG 3. Reference numerals in FIG 3 correspond to the signs for components of the CRH1-type structure. The three-phase alternating current of (220KV for high-speed train) is inputted to the primary side of the traction transformer, and the secondary side of the traction transformer outputs the single-phase alternating current of 27.5KV (rated voltage is 25KV) and 50HZ that is transmitted to the cutout switch K1 or K2 via the single-phase pantograph Ti or T2, and then through a grounding switch 1, a main circuit breaker 2, a voltage measuring transformer 3, a filter 4, a current transformer 5, a surge arrester (lightning arrester) 6, a main transformer 7 and a main converter 8, wherein the direct current outputted by the main converter 8 is divided into two ways: the first way is directly connected to the auxiliary power supply system of the basic circuit, i.e., being transmitted to the charger 13 through the auxiliary converter 11 and through the filter transformer 12, the direct current outputted from the charger 13 charges the battery 15 through the battery switch 14 and simultaneously is coupled with the DC 110V in the car through the diode and the DC switch 16; and the second way powers the tractor motor 10 with electric power through the traction converter 9.
According to one embodiment of the present invention, the following changes are made to the above-mentioned existing basic circuit: as shown in FIG. 3, between the main converter 8 and the auxiliary converter 11 of the basic circuit, a connecting line 100 with a terminal A is led out; and a bidirectional switch K3 is added between the main converter 8 and the traction converter 9, the B-B end of K3 is in connection when the basic circuit is electrified.
Composite circuit:
The onboard power supply device according to the present invention includes a onboard driving power supply and auxiliary power supply circuit, and an onboard power storage and discharge circuit, wherein the onboard driving power supply and auxiliary power supply circuit and the onboard power storage and discharge circuit constitute a composite circuit. Fig. 1 shows an onboard composite-circuit diagram according to one embodiment of the present invention, in which DC current outputted from the main converter 8 is coupled to an auxiliary power supply system at the terminal A
of the lead-out line of the basic circuit via an uncontrollable diode 1. The output end of the onboard power storage and discharge circuit is connected to the terminal C of a bidirectional on-off switch K3 of the basic circuit via an uncontrollable diode 2.
Fig. 5 is a schematic diagram showing the driving power supply, auxiliary power supply, and the onboard power storage and discharge circuit of the 8-car EMU
according to the present invention. The two-way single-phase alternating current circuits a and //of 27.5KV (rated voltage 25KV) outputted from the traction transformer secondary side is coupled to the traction contact power grid, and inputted into the onboard power supply system via the dual-phase pantograph Ti or T2, as shown in Fig. 5. According to one embodiment of the present invention, the onboard power storage and discharge circuit includes a onboard driving power supply and auxiliary power supply system provided as a basic unit TUB1, and an onboard power storage and discharge circuit provided as a basic unit TUB2, which two units are independent of each other and insulated from each other.
When the motor car comes to section LI, Ti is raised, while T2 is lowered, and is connected to the two-phase cutout switch K r, K1. When the motor train comes to the next section LI, Ti is lowered, while T2 is raised and connected to the two-phase cutout switch K2a, K2fi. When T1 is raised and T2 is lowered or T1 is lowered and T2 is raised, the a phase of the two-way single-phase circuit is connected to the onboard driving power supply and auxiliary power supply system TUB1 via the cutout switch K1 or K2a, and the //phase of the two-way single-phase circuit is connected to the onboard power storage and discharge circuit TUB2 via the cutout switch K Ifi or K2fi. Regardless of whether the motor car comes to the section Li or to next section LI, the single-phase circuit a is always connected to the onboard driving power supply and auxiliary power supply system TUB1, and the single-phase circuit i3 is always connected to the onboard power storage and discharge circuit TUB2, which can guarantee that the frequency of the power grid is always 50HZ, the phase sequence and the power grid are the same and are strictly synchronized, and the voltage waveform is a sine wave. When the motor car runs to the section L2, both Ti and T2 are lowered, and the energy stored in the onboard power storage and discharge circuit feeds the onboard driving power supply and auxiliary power supply, that is, the output end of the onboard power storage and discharge circuit is connected to the terminal C of the bidirectional on-off switch K3 of the basic circuit via the uncontrollable diode 62. At this moment, the B-B of the bidirectional disconnect switch K3 is turned off, and the B-C of the bidirectional on-off switch K3 is turned on, so that the energy stored in the onboard power storage and discharge circuit powers the traction motor 10 via the traction converter 9 of the basic circuit. Thus, in accordance with the embodiment of the present invention, there is no power grid in the section L2 and no support structure for the grid. However, a large current step-down resistor is added to the ON and OFF ends of the two-way single-phase electric circuits a and /3 overhead lines, as a result of which it is possible to avoid short-circuit spark of the dual-phase pantograph accessing the traction power supply grid or disconnection spark of the dual-phase pantograph disengaging the traction power supply grid.
According to the embodiment of the present invention, the transmission line for the single-phase electric circuit a is basically the same as the basic circuit of CRH1 type, except that the lead-out connecting line 100 is added between the main converter 8 and the auxiliary converter; in the basic circuit of the single-phase electric circuit # transmission line the DC output end of the main converter is connected to the input end of the onboard power storage and discharge circuit, a on-off switch K3 is added to the output end of the onboard power storage and discharge circuit, the on-off switch K3 is connected to the traction converter, and the traction converter supplies the motor with electric energy, thereby constituting the composite circuit.
It can be seen from the connection relationship between the basic circuit and the composite circuit that the direct current outputted from the main converter 8 of the composite circuit is also transmitted to the onboard auxiliary power supply system of the basic circuit, so as to meet the need of the auxiliary power supply for enabling the motor car to come to the section L2, as a result of which the capacities of the auxiliary converter 11, the transformer of the filter transformer 12 and the battery 15 of the basic circuit should be increased, and further the capacity of the battery 15 should be greater than or equal to a sum of the capacity of the original CRH1-type EMU battery and the electric energy required by the motor car to come to the section L2, in order to ensure the auxiliary power supply for the motor car. Since the battery pack 15 of the original CRH1-type 8-car EMU is a lead acid battery pack or nickel chromium battery pack, the present invention uses a lithium ion battery pack for replacing it, which can reduce the weight and space occupied by the battery pack; the output end of the onboard power storage and discharge circuit cannot be directly connected to the power system of the composite circuit, and only when the motor car runs to the section L2, it is required to feed the power system with electricity. Thus, the output end of the onboard power storage and discharge circuit needs to be connected to the power system of the basic circuit via the terminal C of the bidirectional on-off switch K3 of the basic circuit. The energy stored in the high capacity battery pack 67 of the onboard power storage and discharge circuit must be greater than or equal to a sum of the initially-stored energy and the energy required to enter the segment L2 in order to ensure the operation of the power system, and therefore the capacity of the high capacity battery pack 67 needs to be greatly increased. A graphene battery pack, a hydrogen fuel cell stack or a lithium-powered battery pack is used as the power storage and discharge device required by the high capacity battery pack, which can reduce the weight and space of the energy storage device and also comply with the technical development prospect.
Onboard power storage and discharge circuit: according to one embodiment of the present invention, as shown in FIG. 2, the main functions of the onboard power storage and discharge circuit are to store and discharge the electric power, and it is comprised of a supercapacitor pack and a high capacity battery pack as the core components, in combination with a bidirectional switch and a controller. The greatest advantage of the supercapacitor pack is the high power density, and the greatest advantage of the high capacity battery pack is the large energy capacity. Their combination can provide the energy buffering effect for the high capacity battery pack, and also can give full play to the high-power supply capability of the supercapacitor pack. The bidirectional switch is composed of two power MOSFETs thyristors or IGBT thyristors. The fully-controlled thyristor is a composite device represented by an insulated gate bipolar transistor IGBT. In the power storage and discharge circuit of FIG. 2, the current sensor 612 is connected to the B-C of the bidirectional on-off switch K3 in the basic circuit via the main circuit disconnect switch 613. The charging and discharging process of the onboard power storage and discharge circuit according to the present invention is described as follows:
the charging process of the onboard main circuit, the single-phase electric circuit fl of the composite circuit outputs the direct current via the main converter 8, the negative pole of the direct current being the negative pole of the main circuit input terminal.
As shown in Figure 2, the output positive pole of the main converter 8 is connected to the input end of the charging snubber circuit 63. The circuit of the charging buffer 63 after being connected in parallel with the short-circuit contactor and the charging current-limiting resistor R is coupled in series with the positive pole of the main circuit. A voltage sensor 65 bridging the main circuit inputs a signal to the controller 64, and the signal outputted by the controller 64 controls the on or off state of the short-circuit contactor.
When the supercapacitor pack voltage is lower than a lower limit, the signal outputted by the controller 64 makes the short-circuit contactor disconnected, and the charging current-limiting resistor R is given access to the circuit so as to limit the instantaneous charging current when the electric power is supplied; and when the supercapacitor pack voltage is higher than the lower limit, the signal outputted by the controller 64 pulls in the short-circuit contactor to short-circuit the charging current-limiting resistor R. The supercapacitor pack 66 is bridged between the positive and negative poles of the main circuit via a current sensor 69-1. The current inputted from the main circuit input end charges the supercapacitor pack 66 via the charging snubber circuit. When the supercapacitor pack is fully charged, the current through the current sensor 69-1 is zero, and the output signal from the current sensor is transmitted to the input end of the controller 64, so that the controller 64 controls the gates of the thyristors VT1 and VT2 of the bidirectional switch 610, and only one of the VT1 and VT2 can be turned on. The signal outputted from the controller 64 turns on the thyristor VT1 of the bidirectional switch 610, and the electrical current charges the high capacity battery pack 67 via the thyristor VT1 and freewheeling diode VD2. The operation is repeated until the high capacity battery 67 is fully charged with the electric energy, so that the current signal inputted to the controller 64 from a current sensor 69-2 is zero, or the voltage of the main circuit voltage sensor 65 is equal to the voltage of the voltage sensor 68 of the high capacity battery pack 67, the signal of the controller 64 is inputted via the current sensor 69-2 or voltage sensor 65, voltage sensor 68 output end of the high capacity battery pack;
the output control signal of the controller 64 turns on the thyristor VT2 of the bidirectional switch 610; and the high capacity battery pack 67, via the current sensor 69-2, the thyristor VT2 of the bidirectional switch610 and the freewheeling diode VD1, transmit the electrical current through the current sensor 612 and via the on-off switch 613 to the output end of the main circuit. When the supercapacitor pack 66 completes charging for the high capacity battery pack 67, the thyristor VT1 of the bidirectional switch 610 is turned off. Only the supercapacitor pack 66 continues to participate in the rectification and outputting, forming hot backup, so as to ensure the stability of voltage at the output end.
At this time, it can function as a partial UPS. As for the discharging process of the onboard main circuit, as shown in the composite circuit of Figure 1, the current sensor 612 is connected to the on-off switch K3 in the basic circuit of Fig. 3 via the disconnect switch 613, in which B-B of the bidirectional on-off switch K3 in the basic circuit of Fig. 3 is disconnected, and B-C of the bidirectional on-off switch K3 is turned on. The output end of the onboard main circuit is connected to the terminal C of the B-C of the bidirectional on-off switch K3 in Fig. 3 through the uncontrollable diode 62, and is transferred to the traction motor 10 from the terminal C via the extraction inverter 9, so as to complete the discharging process of the onboard main circuit.
The supercapacitor pack 66 is used as an energy buffer of the main circuit in the motor car, which can share the instantaneous power burden of the high capacity battery pack 67. This depends on the actual load of the external AC power input and DC
power output. The short-term power fluctuation or transient over-voltage and under-voltage are mainly borne by the supercapacitor pack 66, and the main part of the load fluctuation for longer time is borne by the high capacity battery pack 67. The supercapacitor pack 66 can reach the full power output in tens of seconds, so it can be used as energy filter, so that the instantaneous grid fluctuations are completely stored by the capacitor packs, and can be outputted as much as possible through the output current sensor 612 and the disconnect switch 613 so as to meet the requirement of high power, and also it is possible to bear the transient overvoltage and under-voltage and avoid the instantaneous voltage drop so that the instantaneous grid fluctuation current is completely stored by the capacitor group.
When an instantaneous high pulse power output is required, the supercapacitor pack 66 can meet the high power requirements, and can effectively protect the high capacity battery pack 67 to improve the overall safety of the high capacity battery pack. The supercapacitor pack 66 can work in a state of charge instantaneously, and the main purpose is to stabilize the bus voltage, ensure reliability of the output power, and play a role of controlling the electrical energy supply or load fluctuations by Peak-cut. The electrolytic capacitor 611 bridged between the positive and negative poles of the main circuit can function as a high frequency filter. When the high capacity battery pack 67 is fully charged, the electrical current is transmitted to the locomotive power supply system through the output current sensor 612 and the disconnect switch 613. The voltage sensor 65 is bridged between the positive and negative poles of the main circuit, and its signal output end is connected to the signal input end of the controller 64. The voltage sensor 68 of the high capacity battery pack is bridged between both ends of the high capacity battery pack 67, and its signal output end is connected to the input end of the controller 64. The signal output ends of the current sensor 69-1 of the supercapacitor pack and of the current sensor 69-2 of the high capacity battery pack are respectively connected to the controller 64, and the signal output end of the output current sensor 612 is connected to the controller 64. The signal output ends of the controller 64 are connected to the gates of the thyristor VT1 or VT2 of the bidirectional switch 610, respectively, and the signal output end of the controller 64 is connected to the voltage snubber circuit, and the output end of the controller 64 is connected to the disconnecting switch 613.
The onboard power storage and discharge circuit according to the embodiment of the present invention includes the components such as the supercapacitor pack, high capacity battery pack, and fully-controlled thyristor. The maximum advantage of the supercapacitor is that the power density is high, up to 300 W/kg - 5000 W/kg, which is dozens of times of the ordinary battery. The supercapacitors can provide the high- current discharge capacity, the high ultrastrong power conversion efficiency, with the high current energy cycle efficiency > 90%, and the charging current up to 1500A - 3000A. Only several seconds are required to fully charge one single supercapacitor, and hundreds of supercapacitors connected in series can be charged by more than 95% in just tens of seconds to 6 minutes.
In addition, it is a long cycle life, and the number of deep charging and discharging cycles can reach 500,000 times. The supercapacitors have the good temperature characteristics,

17 and the using ambient temperature can be in the range of -40 C to +70 C.
Since the raw material composition, production, use, storage and dismantling processes of the supercapacitor produce no pollution, it is a green product. The supercapacitor can be directly charged without load resistance, and it also has the battery characteristics. It is a new special component between the battery and the capacitor. Although the specific energy of the supercapacitor is much larger than electrolytic capacitor, the specific energy of the supercapacitor is still lower than that of battery. At present, the maximum electric capacity of each electric double layer supercapacitor can reach 10,000F.
However, when the voltage of the existing supercapacitor exceeds the nominal voltage, the electrolyte will be decomposed, shortening the lifetime. In recent years, a new supercapacitor developed in Japan has the nominal voltage of more than 100V. The high capacity battery has the advantages of high energy density, and it can have the theoretical specific energy of up to 400W.h/kg, and charging and discharging lifetime of up to 1000-5000 times.
Here, the graphene battery is a new type of battery, which can shorten the charging time of several hours to less than one minute. The storage capacity of the graphene polymer material battery is three times that of the current best products. Hydrogen fuel cells, which produce water and heat only, are free from pollution to the environment and noise, and fuel hydrogen comes from the electrolysis products of water and decomposition products of other carbohydrates, thus being the current most promising new energy source.
The chemical properties of hydrogen are active, and it can be absorbed by certain metals or alloy compounds to form a metal hydrogen compound, and further the content of hydrogen is high, even higher than the density of liquid hydrogen, being a good hydrogen-storage material. The large-capacity lithium-ion battery has been tested on several types of electric vehicles, and the electric vehicles can travel for 345km on a single charge. There is no need to discharging prior to each charging, the charging can be made at any time, and there is no toxic substance. The supercapacitor pack or high capacity battery pack is a combination formed by connecting the singles in parallel and in series, and the individual supercapacitors or battery are first connected in parallel to achieve the required electrical energy capacity, and then connected in series to achieve the required rated voltage. The supercapacitor pack has the high power density and the high capacity battery have the great energy capacity, and their coordinated combination can both provide energy buffering for the high capacity battery pack, and also can give full play to the high-power electricity supply capability of the supercapacitor pack, thus being a best way of energy storage structure of the supercapacitor pack and the high capacity battery pack.

18 The bidirectional switch consists of the thyristor VT1 and thyristor VT2, and is a fully-controlled device, and the fully-controlled device is characterized by the fact that it can be both turned on and turned off by controlling the gate. The composite device represented by an insulated gate bipolar transistor (IGBT) is a composite of MOSFET and BJT, wherein the IGBT is an insulated gate bipolar transistor, which is a combinative product of MOSFET and GTR (power transistor), and its breakdown voltage can reach 1200V, and the maximum saturation current of the collector has exceeded 1500A.
The converter using IGBT as the inverter device has a capacity of more than 250kVA
and an operating frequency of up to 20kHz.
Although the present invention has been illustrated and described with respect to the embodiments, it will be appreciated by those skilled in the art that various changes and modifications can be made without departing from the scope of the invention.

19

Claims (12)

1. A traction power supply system for a high speed train, comprising an onboard power supply device, the onboard power supply device comprising an onboard driving power supply and auxiliary power supply circuit, and an onboard power storage and discharge circuit, wherein the onboard driving power supply and auxiliary power supply circuit and the onboard power storage and discharge circuit constitute a composite circuit, wherein two-way single-phase electric circuits a and # from a secondary side of a traction transformer of a traction power supply grid are conducted to the onboard power supply device by means of dual-phase pantographs T1 and T2, when one of the dual-phase pantographs T1 and T2 is raised, another of the dual-phase pantographs T1 and T2 must be lowered, or both the dual-phase pantographs T1 and T2 can be lowered, wherein the single-phase electric circuit a is always connected to the onboard driving power supply and auxiliary power supply circuit, the single-phase electric circuit # is always connected to the onboard power storage and discharge circuit, and the onboard driving power supply and auxiliary power supply circuit and the onboard power storage and discharge circuit are independent of each other and insulated from each other.

2. A traction power supply system according to claim 1, characterized in that, the onboard power storage and discharge circuit includes a combination of supercapacitors and high capacity battery.

3. A traction power supply system according to claim 1 or 2, characterized in that, the onboard driving power supply and auxiliary power supply circuit includes an onboard basic circuit, wherein the onboard basic circuit is divided into two ways by direct current outputted from a main converter: a first way is directly connected to an auxiliary power supply system via an auxiliary converter, while a second way feeds a traction motor through a traction converter so as to be connected to a driving power supply system, wherein a lead-out connecting line having a terminal A is added between the main converter and the auxiliary converter; a bidirectional switch K3 is added between the main converter and the traction converter, and when a C terminal of B-C of the bidirectional switch K3 is turned on, a B-B wire of the bidirectional switch K3 is turned off.

4. A traction power supply system according to claim 3, characterized in that, when the motor car comes to section L1, the single phase electric circuit a is transmitted to the dual-phase pantograph T1 from the traction power supply grid and inputted into the car through a two-phase cutout switch K1.alpha. , or when the motor car comes to the next section L1, the single-phase electric circuit .alpha. is transmitted to the dual-phase pantograph T2 from the traction power supply grid and inputted into the car through a two-phase cutout switch K2.alpha. , the single-phase electric circuit .alpha. feeding the onboard driving power supply and auxiliary power supply circuit; when the motor car comes to the section L1, the single phase electric circuit .beta. is transmitted to the dual-phase pantograph T1 from the traction power supply grid and inputted into the car through a two-phase cutout switch K1.beta., or when the motor car comes to the next section L1, the single-phase electric circuit .beta. is transmitted to the dual-phase pantograph T2 from the traction power supply grid and inputted into the car through a two-phase cutout switch K2.beta., wherein the single-phase electric circuit .beta. is divided into two ways by direct current outputted from the main converter: one way is directly connected through a diode to the terminal A of the connecting line led out from between the main converter and the auxiliary converter of the basic circuit, while an another way is connected from an output end of the onboard power storage and discharge circuit to the terminal C of the bidirectional switch K3 of the basic circuit through the diode, the diode preventing the electrical current energy from flowing back.

5. A traction power supply system according to claim 4, characterized in that, the main converter of the composite circuit is connected to the terminal A of the connecting line of the basic circuit via the diode, and the terminal A in turn is connected to the auxiliary converter of the basic circuit, so that the auxiliary power supply of the composite circuit and the auxiliary power supply of the basic circuit have a common auxiliary power supply system; and the auxiliary converter, a transformer of a filter transformer and a battery of the common auxiliary power supply system have an increased capacity, wherein the battery is a lithium ion battery having a capacity greater than or equal to a sum of the capacity of the battery of the basic circuit and the auxiliary supply power amount required by the motor car to come to section L2.

6. A traction power supply system according to any one of claims 3 to 5, characterized in that, the electrical current outputted from the onboard power storage and discharge circuit is connected to the terminal C of the bidirectional switch K3 of the basic circuit via the diode and enters into the driving power supply system of the basic circuit, at this moment, B-B of the bidirectional switch K3 is turned off, power supplying of the composite circuit and power supplying of the basic circuit have a common power supply system, and the onboard power storage and discharge circuit has a high capacity battery with the increased energy capacity, wherein the rated voltage of the high capacity battery pack is matched with the voltage of a traction inverter, the energy capacity of the high capacity battery pack is greater than or equal to the energy required by the motor car to come to the section L2, and the high capacity battery pack is formed by connecting graphene cells, hydrogen fuel cells and lithium ion cells in parallel and in series.

7. A traction power supply system according to any one of claims 3 to 5, characterized in that, the onboard power storage and discharge circuit is direct current outputted by the single-phase electric circuit II via the main converter, the negative pole of the direct current is connected to the negative pole of the main circuit of the onboard power storage and discharge circuit, the positive pole of the direct current is inputted into a charging snubber circuit, the charging snubber circuit after being connected in parallel with a short-circuit contactor and a charging current-limiting resistor is coupled in series with the positive pole of the main circuit, wherein when the voltage of the supercapacitor pack is smaller than a lower limit, the short-circuit contactor is turned off to let the charging current-limiting resistor have access to the circuit, thus limiting the instantaneous charging current when supplying the power; and when the voltage of the supercapacitor pack is higher than the lower limit, the signal outputted from a controller pulls in the short-circuit contactor to cut off the charging current-limiting resistor, the supercapacitor pack is bridged between the positive and negative poles of the main circuit, and the electrical current outputted from the charging snubber circuit charges the supercapacitor pack.

8. A traction power supply system according to claim 7, characterized in that, when the supercapacitor pack is fully charged by the electrical current outputted from the charging snubber circuit, electrical current through a current sensor of the supercapacitor pack is zero, and a signal is outputted to the controller; a signal output end of the controller inputs the signal into the gate of the bidirectional switch's VT1, and VT1 is switched on; the high capacity battery pack is charged via the current sensor and the bidirectional switch's VT1, and via a freewheeling diode VD2; and the E-pole of the bidirectional switch's VT1 and the E-pole of the VT2 are connected together, only one being in an ON state.

9. A traction power supply system according to claim 7, characterized in that, when the high capacity battery pack is fully charged with the electrical current, i.e., electrical current through the current sensor of the high capacity battery pack is zero, or when the voltage sensor bridged between the positive and negative poles of the supercapacitor pack is equal to the voltage sensor bridged between the high capacity battery packs, the high capacity battery packs discharge, and at this moment the signal output end of the controller is inputted and the bidirectional switch's VT2 is switched on, and the high capacity battery pack discharges to the main circuit output end through the current sensor and the bidirectional switch's VT2 and the freewheeling diode VD1.

10. A traction power supply system according to claim 9, characterized in that, the main converter of the main circuit is connected to the C-end of the bidirectional switch K3 of the basic circuit via an uncontrollable diode, turning off the B-B and turning on the B-C of the bidirectional switch K3, and connected to the traction converter of the basic circuit via the B-C, and then the traction motor is supplied with power by the traction converter; the supercapacitor pack acts as an energy buffer of the main circuit to share the instantaneous power burden of the high capacity battery pack, wherein short-term power fluctuation or instantaneous over-voltage and under-voltage are mainly borne by the supercapacitor pack, and the main part of the load fluctuation for longer time is borne by the high capacity battery pack, an electrolytic capacitor bridged between the positive and negative poles of the main circuit is used as a high frequency filter, and the positive pole of the main circuit is connected to the input end of the driving power supply energy storage and discharge circuit through the output current sensor.

11. A traction power supply system according to claim 10, characterized in that, the positive pole of the main circuit is connected to the driving power supply system through the output current sensor and the disconnect switch, the voltage sensor is bridged between the positive and negative poles of the main circuit, with its signal output end being connected to the signal input end of the controller; the voltage sensor of the high capacity battery pack is bridged between both ends of the high capacity battery pack, with its output signal being transmitted to the input end of the controller, the signal output ends of the current sensor of the supercapacitor pack and the current sensor of the high capacity battery pack connect to the controller respectively, while the signal output ends of the output current sensor connect to the controller respectively; the signal output ends of the controller are respectively connected to the gates of VT1 or VT2, the output end of the controller is connected to the voltage snubber circuit, and the output end of the controller is connected to the disconnect switch.

12. A high speed train, characterized by comprising a traction power supply system according to any one of claims 1-11.