CN210351038U

CN210351038U - Low-loss urban rail transit bidirectional converter

Info

Publication number: CN210351038U
Application number: CN201921715568.6U
Authority: CN
Inventors: 胡顺全; 吴建华; 尹彭飞; 丁宁; 姬脉胜; 亢丽平; 邵景红; 张岩; 王卫国
Original assignee: Shandong Windsun Electronics Science & Technology Co ltd
Current assignee: Shandong Windsun Electronics Science & Technology Co ltd
Priority date: 2019-10-14
Filing date: 2019-10-14
Publication date: 2020-04-17
Anticipated expiration: 2029-10-14

Abstract

The utility model discloses a low-loss type urban rail transit bidirectional converter, including isolation transformer T1, uncontrollable rectifier unit A1 and A4, DC/AC bidirectional conversion unit A2 and A3, isolation transformer T1 is provided with 1 primary winding and 2 secondary windings, A1 is a set with A2 and connects in parallel, its direct current side all connects on the direct current traction electric wire netting, its alternating current side connects on a secondary winding of isolation transformer T1 simultaneously; a3 and A4 are in parallel, and the alternating current side of the A3 and the A4 are simultaneously connected with the other secondary winding of T1. The utility model discloses a low-loss type urban rail transit bidirectional converter, when the rectification mode, A1, A4 are in uncontrollable rectification mode, and calorific capacity is compared controllable rectification and is very little, and the harmonic current that A2, A3 unit compensation A1, A4 work brought through mode that both combine has both reduced the loss, has also guaranteed to take the harmonic of supplying power network for the interchange at less numerical value relatively.

Description

Low-loss urban rail transit bidirectional converter

Technical Field

The utility model relates to a bidirectional converter, more specifically the theory that says so especially relates to a low-loss type urban rail transit bidirectional converter.

Background

The subway adopts a direct current traction power supply mode, a traction substation adopts a diode uncontrollable rectification mode, energy can only flow from an alternating current side to a direct current side, and the energy only has one-way fluidity. When the train is regeneratively braked, the electric working condition of the traction motor is converted into the power generation working condition, the kinetic energy of the train is converted into electric energy, most of the electric energy is fed back to the direct-current traction network except for part of the electric energy consumed by the auxiliary power equipment of the regenerative train, and a set of regenerative braking energy absorption device is generally arranged to absorb the redundant regenerative electric energy, so that the network voltage is kept stable, and the regenerative braking capacity of the train is exerted to the maximum extent.

Disclosure of Invention

The utility model discloses an overcome above-mentioned technical problem's shortcoming, provide a low-loss type urban rail transit bidirectional converter.

The utility model discloses a low-loss type urban rail transit bidirectional converter, including isolation transformer T1, uncontrolled rectifier unit A1, DC/AC bidirectional conversion unit A2, DC/AC bidirectional conversion unit A3 and uncontrolled rectifier unit A4, isolation transformer T1 is provided with 1 primary winding and 2 secondary windings, isolation transformer T1's primary winding is connected with the AC supply network; the method is characterized in that: the uncontrolled rectifying unit A1 and the DC/AC bidirectional conversion unit A2 are combined and connected in parallel, the direct current sides of the uncontrolled rectifying unit A1 and the DC/AC bidirectional conversion unit A2 are connected to a direct current traction power grid, and the alternating current sides of the uncontrolled rectifying unit A1 and the DC/AC bidirectional conversion unit A2 are simultaneously connected to a secondary winding of an isolation transformer T1; the DC/AC bidirectional conversion unit A3 and the uncontrolled rectifier unit A4 are combined and connected in parallel, the direct current sides of the units are connected to a direct current traction power grid, and the alternating current sides of the units are simultaneously connected to the other secondary winding of the isolation transformer T1.

The utility model discloses a low-loss type urban rail transit bidirectional converter, including filter capacitor C1, filter capacitor C1's both ends connect respectively on the positive, negative bus of direct current traction electric wire netting.

The utility model discloses a low-loss type urban rail transit bidirectional converter, under the contravariant state, do not control rectifier unit A1 and do not control rectifier unit A4 and do not work, DC/AC bidirectional conversion unit A2 and DC/AC bidirectional conversion unit A3 are in the contravariant mode; in the rectified state, the uncontrolled rectifying unit a1 and the uncontrolled rectifying unit a4 are in an uncontrolled rectifying mode, and the DC/AC bidirectional converting units a2, A3 are used to compensate for current harmonics caused by the uncontrolled rectifying units a1, a4 to the AC supply network.

The utility model has the advantages that: the utility model discloses a low-loss type urban rail transit bidirectional converter, work when the contravariant mode, do not control rectifier unit A1, A4 and do not work, A2, A3 unit work in the contravariant mode. When the low-loss type urban rail transit bidirectional converter works in a rectification mode, the uncontrolled rectification units A1 and A4 are in an uncontrolled rectification working mode, and the A2 and A3 compensate harmonic currents caused by the work of A1 and A4. The switching frequency of the A1 and A4 work is only 50Hz, the main current is supplied, the heating value is very small compared with controllable rectification, the current harmonic wave brought to an alternating current supply network is relatively large, in this case, the harmonic wave compensation function is supplied by the A2 and A3, the supplied current is not large, and the loss is relatively small. By combining the two modes, the loss is reduced, and the harmonic waves brought to the alternating current power supply network are ensured to be in a relatively small value.

Drawings

Fig. 1 is the circuit schematic diagram of the low-loss urban rail transit bidirectional converter of the present invention.

In the figure: 1 direct current traction power grid, 2 alternating current power supply network, 3 isolation transformer T1, 4 filter capacitor C1. Uncontrolled rectifying unit A1, DC/AC bidirectional transformation unit A2, DC/AC bidirectional transformation unit A3, uncontrolled rectifying unit A4.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings and examples.

As shown in fig. 1, the utility model discloses a low-loss type urban rail transit bidirectional converter's circuit schematic diagram, it is by isolation transformer T1 (3), filter capacitor C1 (4), uncontrollable rectifier unit A1, uncontrollable rectifier unit A4, DC/AC bidirectional converter unit A2 and DC/AC bidirectional converter unit A3 are constituteed, isolation transformer T1 realizes voltage conversion and electrical apparatus isolation effect, it is provided with 1 primary winding and 2 secondary winding, isolation transformer T1's primary winding is connected with AC supply network 2, filter capacitor C1's both ends connect on DC traction electric wire netting 1, with the alternating signal on the filtering DC traction electric netting, realize DC traction electric netting 1's steady voltage.

The uncontrolled rectifying unit a1 and the DC/AC bidirectional conversion unit a2 are shown as a group, and are arranged in parallel, the positive and negative terminals of the DC sides of a1 and a2 are respectively connected to the positive and negative buses of the DC traction grid 1, and the terminals of the AC sides of a1 and a2 are respectively connected to a secondary winding of an isolation transformer T1. The uncontrolled rectifying unit A4 and the DC/AC bidirectional conversion unit A3 are in a group and are also arranged in a parallel mode, positive terminals and negative terminals of direct current sides of A3 and A4 are respectively connected to a positive bus and a negative bus of the direct current traction power grid 1, and terminals of alternating current sides of A3 and A4 are respectively connected to the other secondary winding of the isolation transformer T1.

The utility model discloses a low-loss type urban rail transit bidirectional converter can work at two kinds of mode of rectification and contravariant, and rectification mode is that direct current electric energy is converted into with alternating current electric energy and send to the direct current and pull the electric wire netting, and contravariant mode is that alternating current electric energy is converted into with direct current electric energy and send to the alternating current supply network.

In an inversion working mode, the uncontrolled rectifying unit A1 and the uncontrolled rectifying unit A4 do not work, the DC/AC bidirectional conversion units A2 and A3 work, direct current on the direct current traction power grid 1 is inverted into alternating current under the action of a control signal and then is input to the secondary side of the isolation transformer T1, and then is input to the alternating current power supply network 2 after voltage conversion of the isolation transformer T1, so that energy feedback during train braking is realized.

In the rectification working mode, alternating current on the alternating current supply network 2 is transformed by an isolation transformer T1, and then is converted into direct current through uncontrolled rectification of uncontrolled rectification units A1 and A4, and the direct current is input to the direct current traction power grid 1 to supply the train to work. Since the switching frequency of the operation of the uncontrolled rectifier units a1 and a4 is only 50Hz, they supply the main current, the heat generation is very small compared with the controlled rectifier, but the current harmonics brought to the ac supply network are relatively large, in which case the harmonic compensation function provided by a2 and A3 provides a small current and relatively small loss. By combining the two modes, the loss is reduced, and the harmonic waves brought to the alternating current power supply network are ensured to be in a relatively small value.

Claims

1. A low-loss urban rail transit bidirectional converter comprises an isolation transformer T1 (3), an uncontrolled rectifying unit A1, a DC/AC bidirectional conversion unit A2, a DC/AC bidirectional conversion unit A3 and an uncontrolled rectifying unit A4, wherein an isolation transformer T1 is provided with 1 primary winding and 2 secondary windings, and the primary winding of the isolation transformer T1 is connected with an alternating current power supply network; the method is characterized in that: the uncontrolled rectifying unit A1 and the DC/AC bidirectional conversion unit A2 are combined and connected in parallel, the direct current sides of the uncontrolled rectifying unit A1 and the DC/AC bidirectional conversion unit A2 are connected to a direct current traction power grid, and the alternating current sides of the uncontrolled rectifying unit A1 and the DC/AC bidirectional conversion unit A2 are simultaneously connected to a secondary winding of an isolation transformer T1; the DC/AC bidirectional conversion unit A3 and the uncontrolled rectifier unit A4 are combined and connected in parallel, the direct current sides of the units are connected to a direct current traction power grid, and the alternating current sides of the units are simultaneously connected to the other secondary winding of the isolation transformer T1.

2. The low-loss type urban rail transit bidirectional converter according to claim 1, wherein: the direct-current traction power supply comprises a filter capacitor C1 (4), wherein two ends of the filter capacitor C1 are respectively connected to a positive bus and a negative bus of a direct-current traction power grid (1).

3. The low-loss urban rail transit bidirectional converter according to claim 1 or 2, characterized in that: in an inversion state, the uncontrolled rectifying unit A1 and the uncontrolled rectifying unit A4 do not work, and the DC/AC bidirectional conversion unit A2 and the DC/AC bidirectional conversion unit A3 are in an inversion mode; in the rectified state, the uncontrolled rectifying unit a1 and the uncontrolled rectifying unit a4 are in an uncontrolled rectifying mode, and the DC/AC bidirectional converting units a2, A3 are used to compensate for current harmonics caused by the uncontrolled rectifying units a1, a4 to the AC supply network.