CN210881738U

CN210881738U - High-power bidirectional charger

Info

Publication number: CN210881738U
Application number: CN201921424140.6U
Authority: CN
Inventors: 杨欣然; 赵建荣; 孟向军; 吕淼; 徐关澄; 孙亮; 王林
Original assignee: Xian XJ Power Electronics Technology Co Ltd
Current assignee: Xian XJ Power Electronics Technology Co Ltd
Priority date: 2019-08-29
Filing date: 2019-08-29
Publication date: 2020-06-30
Anticipated expiration: 2029-08-29

Abstract

The utility model discloses a high-power bidirectional charger, including the multiple winding transformer, equal electricity is connected with a machine module that charges on every winding of multiple winding transformer, the machine module that charges is including the alternating current filter circuit who connects gradually, AC/DC converter, direct current bus electric capacity, DC/DC converter and direct current filter circuit. The electric isolation is realized through a multi-winding power frequency transformer, and the high-power output is realized through a mode that a plurality of windings are connected with a plurality of charger modules. The problems that the traditional charger cannot realize energy bidirectional flow and single module output power is low due to the fact that a high-frequency isolation circuit is used are solved by adopting a non-isolated AC/DC topology + DC/DC topology.

Description

High-power bidirectional charger

Technical Field

The utility model belongs to the technical field of the two-way charging of high-power car, concretely relates to high-power two-way machine that charges.

Background

With the continuous progress of science and technology, new energy automobiles become more and more popular, and electric automobiles become more and more popular in recent years. With the increase of the endurance mileage of the automobile, the traditional low-power charger cannot meet the actual requirement. The high-power charger can greatly shorten the charging time, and the bidirectional charging and discharging working mode is also suitable for a Vehicle-to-grid (V2G) mode that the electric energy of the Vehicle-mounted battery is sold to a power grid when the electric Vehicle is not used at night, so that the function of the charger is greatly improved, and the application range of the electric Vehicle is expanded.

The conventional charger adopts a traditional topology scheme of Vienna + LLC, is limited by the characteristics of Vienna and LLC resonant converter topology, and cannot meet the requirements of wide battery voltage range and bidirectional energy flow when being applied to a high-power charger under the working condition of V2G. If the direct current power supply is applied to the occasions of high-power chargers, most of the preceding stage rectification topologies used by the traditional chargers are topology schemes such as a Vienna rectifier and a three-phase bridgeless PFC (power factor correction), but the topologies have the condition that the power flow direction can only be from alternating current to direct current and the bidirectional flow of energy cannot be realized. The secondary part of traditional machine that charges is mostly LLC resonant converter high frequency isolation topology, powerful LLC topological circuit design is comparatively complicated, high-power high frequency transformer among the LLC resonant converter keeps apart the volume that makes the module great, the heat dissipation difficulty of module, the LLC topology realizes that bidirectional energy flow control is extremely complicated, voltage control range is little, should not regard as the volume production product to use, powerful machine that charges makes down the cost higher, does not have higher economic nature. Therefore, most of the high-power chargers in the market are formed by connecting 15-20 kW traditional single-phase chargers in parallel, in order to realize high-power charging, an energy distribution switch network consisting of an external huge direct current contactor is needed to realize charging for electric vehicles with different power levels, so that the charger is large in overall size, numerous in modules and capable of realizing single-phase flow of energy, and cannot meet the functional requirement of V2G.

Disclosure of Invention

The utility model provides a high-power bidirectional charger has solved traditional charger power and can not two-way flow, the less problem of single module power.

In order to achieve the above object, a high-power bidirectional charger, including the multiple winding transformer, each electricity is connected with a machine module that charges on every winding of multiple winding transformer, the machine module that charges is including the alternating current filter circuit who connects gradually, AC/DC converter, direct current bus electric capacity, DC/DC converter and direct current filter circuit.

Furthermore, an electromagnetic interference suppression module is connected between each winding of the multi-winding transformer and the charger module.

Further, the AC/DC converter adopts an ANPC three-level alternating current inverter circuit, a linear three-level alternating current inverter circuit, a T-shaped three-level alternating current inverter circuit or a two-level alternating current inverter circuit.

Furthermore, the DC/DC converter adopts a three-phase interleaved Buck-boost circuit, a single-phase Buck-boost circuit, a four-phase interleaved Buck-boost circuit, a single-phase linear three-level topology or a two-phase linear three-level topology interleaved parallel circuit.

Further, the power devices in the AC/DC converter and the DC/DC converter are IGBTs, MOSFETs or silicon carbide type MOSFETs.

The controller 10 is used for generating a control signal according to a control requirement and the received voltage, current and voltage signals of the direct current bus side of the alternating current side; the alternating current driving circuit is used for transmitting a control signal of the controller to a gate pole of a power device in the AC/DC converter after isolating and amplifying the control signal so as to control the output voltage and current of the AC/DC converter; the direct current sampling circuit is used for collecting an inductive current of the direct current filter circuit and a voltage signal at the battery side and transmitting the collected signal to the controller, and the controller 10 generates a control signal according to a control requirement and the received direct current inductive current and the received voltage signal at the battery side; the direct current driving circuit is connected with the controller and the DC/DC converter and is used for transmitting a control signal of the controller to a gate electrode of a power device in the DC/DC converter after isolating and amplifying the control signal, and controlling the output voltage and current of the DC/DC converter.

Compared with the prior art, the utility model discloses following profitable technological effect has at least:

the non-isolated bidirectional high-frequency AC/DC converter and the bidirectional DC/DC converter are used, so that the electric vehicle charger which meets the V2G function requirement and has bidirectional energy flow is realized, and the difficulties of difficult module heat dissipation design and complex bidirectional LLC resonant converter control system caused by the built-in high-frequency transformer when the traditional charger is used for realizing a high-power charger are overcome.

By using the high-frequency switch device and removing the high-frequency isolation transformer, the conversion efficiency of a single charger module is improved, the limitation of the high-frequency isolation transformer is avoided, and the power level of the single module is remarkably improved. At the same time, the parallel connection of a plurality of modules becomes simpler. In order to meet the national standard that the non-vehicle-mounted conductive charger for the electric automobile meets the requirement of electrical isolation between power supply input and direct current output, the alternating current input side adopts a multi-winding transformer to realize electrical isolation, and the national standard requirement is met.

The scheme that the non-isolated high-frequency AC/DC converter and the DC/DC converter are connected in series in two stages solves the problem that the high-power output of the traditional charger needs a plurality of charger modules to be connected in parallel by improving the power level of a single module; the scheme of connecting the non-isolated high-frequency AC/DC converter and the DC/DC converter in series in two stages saves a high-frequency isolation transformer, reduces heating devices in a charger module, effectively reduces the design difficulty of the whole machine, simplifies the thermal design of the whole machine and reduces the research and development cost; the problem that a traditional electric vehicle charger cannot realize bidirectional flow of energy is solved through a scheme that a non-isolated high-frequency AC/DC converter and a DC/DC converter are connected in series in two stages.

Drawings

Fig. 1 is a schematic view of a charging system according to the present invention;

FIG. 2 is a schematic diagram of a charger module of the present invention;

FIG. 3 is an implementation of a charger module;

FIG. 4 is an implementation of a charger module;

fig. 5 is an implementation of a charger module.

In the drawings: 1. the device comprises an alternating current filter circuit, 2, an AC/DC converter, 3, a bus capacitor, 4, a DC/DC converter and 5 and a direct current filter circuit.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1, a charger module of a high-power bidirectional charger realizes electrical isolation through a multi-winding transformer, and each winding of the transformer is connected with a charger module to realize power conversion. The high-power charger comprises a multi-winding transformer 1-1, a first EMI module 1-2, a second EMI module 1-3, … …, an nth EMI module 1-4, a first charger module 1-5, a second charger module 1-6, … … and an nth charger module 1-7, wherein generally, the number of the modules connected in parallel is between 3 and 20. The multi-winding transformer 1-1 achieves an electrical isolation function, one end of the multi-winding transformer is connected with a power grid, different windings at one end of the multi-winding transformer are respectively connected with a first EMI module 1-2, a second EMI module 1-3, … … and an nth EMI module 1-4, the first EMI module 1-2 is connected with a first charger module 1-5, the second EMI module 1-3 is connected with a second charger module 1-6, … …, and the nth EMI module 1-4 is connected with an nth charger module 1-7.

The charger module is as shown in fig. 2, and the inside of the charger module includes: the device comprises an alternating current filter circuit 1, an AC/DC converter 2, a direct current bus capacitor 3, a DC/DC converter 4, a direct current filter circuit 5, an alternating current sampling circuit 6, an alternating current drive circuit 7, a direct current drive circuit 8, a direct current sampling circuit 9 and a controller 10.

The output end of the alternating current filter circuit 1 is connected with an external multi-winding transformer, the input end of the alternating current filter circuit is connected with the alternating current output side of the AC/DC converter 2, the direct current port of the AC/DC converter 2 is connected in parallel with the two ends of the direct current bus capacitor 3, the two ends of the direct current bus capacitor 3 are also connected with one end of the DC/DC converter 4, the other end of the DC/DC converter 4 is connected with the direct current filter circuit 5, and the output of the direct current filter circuit 5 is connected with the storage battery. The alternating current sampling circuit 6 is connected with the AC/DC converter 2 and the controller 10, and is used for sampling voltage and current at the AC side and voltage signals at the DC side in the AC/DC converter 2, conditioning the acquired voltage and current at the AC side and voltage signals at the DC side and transmitting the conditioned voltage and current signals to the controller 10, and the controller 10 generates control signals according to control requirements and the received voltage and current at the AC side and voltage signals at the DC bus side; the alternating current driving circuit 7 is connected with the controller 10 and the AC/DC converter 2, and the alternating current driving circuit 7 is used for transmitting a control signal of the controller 10 to a gate of a power device in the AC/DC converter 2 after isolating and amplifying the control signal so as to control the output voltage and current of the AC/DC converter 2. One end of a direct current sampling circuit 9 is connected with the direct current filter circuit 5, the other end of the direct current sampling circuit is connected with a controller 10, the direct current sampling circuit 9 is used for collecting three-phase inductive current and battery side voltage signals of the direct current filter circuit 5 and transmitting the collected signals to the controller 10, and the controller 10 generates control signals according to control requirements and the received direct current inductive current and battery side voltage signals; the DC driving circuit 8 is connected to the controller 10 and the DC/DC converter 4, and configured to isolate and amplify a control signal of the controller 10, transmit the isolated and amplified control signal to a gate of a power device in the DC/DC converter 4, and control an output voltage and a current of the DC/DC converter 4. The controller 10 is connected with the alternating current sampling circuit 6, the alternating current driving circuit 7, the direct current driving circuit 8 and the direct current sampling circuit 9, so that the output voltage and current of the whole charger module are controlled, and the charging function is realized.

In the above circuit, in order to realize bidirectional energy control, the power devices in the AC/DC converter 2 and the DC/DC converter 4 are selected from IGBT, MOSFET or silicon carbide MOSFET (sic mos for short) fully controlled devices.

As shown in fig. 1 and 2, the charging system is composed of a multi-winding transformer 1-1, a plurality of EMI modules, and a plurality of charger modules, and one EMI module and one charger module are connected to each winding. The multi-winding transformer provides electrical isolation, the electromagnetic interference suppression module (EMI module for short) realizes anti-interference suppression, and the charger module realizes high-power output. The direct current output side of the charger module can be connected in parallel to output or independently used as power output. The charger module has the following embodiments according to different topology choices.

Example 1

As shown in fig. 2, the charger module is a key device for realizing AC/DC power conversion, because the wide voltage range of the DC output of the actual charger is wider, generally between 200V to 950V DC, while the conventional non-isolated AC/DC converter has the limitation of the minimum output voltage under the rectification condition, a one-stage DC/DC converter is added here, and the wide-range voltage output is realized through a two-stage converter topology.

The charger module includes: the device comprises an alternating current filter circuit 1, an AC/DC converter 2, a direct current bus capacitor 3, a DC/DC converter 4, a direct current filter circuit 5, an alternating current sampling circuit 6, an alternating current drive circuit 7, a direct current drive circuit 8, a direct current sampling circuit 9 and a controller 10. The output end of the alternating current filter circuit 1 is connected with an external multi-winding transformer, the input end of the alternating current filter circuit is connected with the alternating current output side of the AC/DC converter 2, the direct current port of the AC/DC converter 2 is connected with the direct current bus capacitor 3 in parallel, the direct current bus capacitor 3 is connected with one end of the DC/DC converter 4, the other end of the DC/DC converter 4 is connected with the direct current filter circuit 5, and the output end of the direct current filter circuit 5 is connected with the storage battery. The direct-current bus capacitor 3 comprises a capacitor C4 and a capacitor C5 which are electrically connected, a node between the capacitor C4 and the capacitor C5 is marked as an A node, the AC/DC converter 2 is an ANPC three-level alternating-current inverter circuit and comprises three groups of power devices which are connected in parallel, the structures of the three groups of power devices are the same, and each group of power devices comprises 6 power devices. The first group of power devices comprises a power device S11, a power device S12, a power device S13, a power device S14, a power device S15 and a power device S16, wherein the power device S11 is connected in series with the power device S14, the power device S15 is connected in series with the power device S16 to form a first series branch, one end of the first series branch is connected between the power device S11 and the power device S12, and the other end of the first series branch is connected between the power device S13 and the power device S14; the second group of power devices comprises a power device S21, a power device S22, a power device S23, a power device S24, a power device S25 and a power device S26, wherein the power device S21 is connected in series with the power device S24, the power device S25 is connected in series with the power device S26 to form a first series branch, one end of the first series branch is connected between the power device S21 and the power device S22, and the other end of the first series branch is connected between the power device S23 and the power device S24; the third group of power devices comprises a power device S31, a power device S32, a power device S33, a power device S34, a power device S35 and a power device S36, wherein the power device S31 is connected in series with the power device S34, the power device S35 is connected in series with the power device S36 to form a first series branch, one end of the first series branch is connected between the power device S31 and the power device S32, and the other end of the first series branch is connected between the power device S33 and the power device S34; a connection point between the power device S15 and the power device S16 is denoted as a1, a connection point between the power device S25 and the power device S26 is denoted as a2, a connection point between the power device S35 and the power device S36 is denoted as A3, and the node a1, the node a2, the node A3, and the node a are electrically connected.

The alternating current sampling circuit 6 is connected with the AC/DC converter 2 and the controller 10, and is responsible for sampling the voltage and current at the alternating current side and the voltage signal at the direct current side in the AC/DC converter 2, conditioning the signals and transmitting the conditioned signals to the controller 10. The alternating current driving circuit 7 is connected with the controller 10 and the AC/DC converter 2, and after isolating and amplifying a control signal of the controller 10, transmits the control signal to a gate of a power device in the AC/DC converter 2 to control the output voltage and current of the AC/DC converter 2. The direct current driving circuit 8 is connected to the controller 10 and the DC/DC converter 4, and after isolating and amplifying a control signal of the controller 10, transmits the control signal to a gate of a power device in the DC/DC converter 4 to control an output voltage and a current of the DC/DC converter 4. The controller 10 is connected with the alternating current sampling circuit 6, the alternating current driving circuit 7, the direct current driving circuit 8 and the direct current sampling circuit 9, so that the output voltage and current of the whole charger module are controlled, and the charging function is realized.

The alternating current filter circuit 1 is an LCL filter and is used for realizing the alternating current filtering function; the AC/DC converter 2 is an ANPC three-level alternating current inverter circuit and is responsible for converting alternating current into high-voltage direct current; the direct current bus capacitor 3 comprises capacitors C4 and C5 which are electrically connected and provide the capability of supporting bus voltage; the DC/DC converter 4 is a three-phase interleaved Buck-boost circuit and is used for converting high-voltage direct current into voltage suitable for a storage battery; the direct current filter circuit 5 realizes an LC filter circuit through an inductor and a capacitor, and reduces current ripples and voltage ripples; the alternating current sampling circuit 6, the alternating current driving circuit 7, the direct current driving circuit 8, the direct current sampling circuit 9 and the controller 10 form a control part of a charger module, so that voltage and current sampling and control are realized, and a charging function is realized. The alternating current sampling circuit 6 collects three-phase alternating current output voltage, three-phase alternating current and direct current bus voltage of the AC/DC converter 2 and is used for the controller to generate a control signal to control the output voltage and current of the alternating current side; the alternating current driving circuit 7 drives the power devices S11-S16, S21-S26, S31-S36 in the AC/DC converter 2 through a driving chip of an IGBT or a MOSFET. The direct current drive circuit 8 drives the power devices S41, S42, S51, S52, S61, and S62 in the DC/DC converter 4 through a drive chip of an IGBT or a MOSFET. The DC sampling circuit 9 collects the inductive current of the DC/DC converter 4 and the voltage signal of the battery side, and is used for the controller to generate a control signal to control the output voltage and current of the DC side.

In the charging mode of the electric automobile, the primary side of a multi-winding transformer 1-1 is connected to a three-phase alternating current power grid, an alternating current filter circuit 1 is connected to the secondary side of the multi-winding transformer 1-1, the voltage and the current of the power grid are filtered through an inductance-capacitance device in the alternating current filter circuit 1, the filtered three-phase alternating current serves as the alternating current input of an AC/DC converter 2, power devices S11-S16, S21-S26 and S31-S36 in the AC/DC converter 2 work in a rectification state to generate a direct current voltage of 750V-1000V, the direct current voltage is filtered through a direct current bus capacitor 3, then the direct current voltage is reduced through a DC/DC converter 4, the voltage is further reduced to the voltage value required by the battery of the electric automobile, the output direct current is filtered through a direct current filter circuit 5, and the filtered direct current is output to the battery of the, and charging is carried out.

In the grid-connected discharge mode of the electric automobile, power flows in from the battery end and flows out from the alternating current side. The energy of the battery of the electric vehicle is output to the DC/DC converter 4 through the DC filter circuit 5. The DC/DC converter 4 works in a boosting mode, the voltage is boosted to 750V-1000V, after filtering is carried out through the direct current bus capacitor 3, the voltage is used as the direct current side input of the AC/DC converter 2, and power devices S11-S16, S21-S26 and S31-S36 in the AC/DC converter 2 work in an inversion state, and direct current is converted into alternating current. Alternating current output by the AC/DC converter 2 is filtered by the alternating current filter circuit 1 and then is connected to the secondary side of the multi-winding transformer 1-1, and the primary side of the multi-winding transformer 1-1 is connected to a three-phase alternating current power grid, so that the energy of the battery of the electric automobile is transmitted to the power grid.

Example 2

Referring to fig. 3, the present embodiment is different from embodiment 1 in that: the AC/DC converter 2 adopts a two-level AC inverter circuit, and the DC/DC converter 4 adopts a two-phase I-shaped three-level topology in staggered parallel connection.

Example 3

Referring to fig. 4, the present embodiment is different from embodiment 1 in that: the AC/DC converter 2 adopts a linear three-level alternating current inverter circuit, and the DC/DC converter 4 adopts two-phase linear three-level topology interleaving parallel connection.

Example 4

Referring to fig. 5, the present embodiment is different from embodiment 1 in that: the AC/DC converter 2 adopts a T-shaped three-level alternating current inverter circuit, and the DC/DC converter 4 adopts a linear three-level topology.

A be applicable to high-power machine that charges, through the parallel mode of a plurality of machine modules that charge, realize the realization of high-power machine that charges, the power of single machine module that charges can reach 100kW, far exceed current machine module power that charges, can realize the high-power output more than 500kW through the parallelly connected of a plurality of machine modules that charge, and because the machine module that charges can use non-isolated topology, there is not high-frequency transformer, the design of the machine module that charges is simple, small in size, convenient maintenance and replacement have certain leading nature. The above contents are only for explaining the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby, and any modification made on the basis of the technical solution according to the technical idea of the present invention all fall within the protection scope of the claims of the present invention.

Claims

1. The high-power bidirectional charger is characterized by comprising a multi-winding transformer (1-1), wherein each winding of the multi-winding transformer (1-1) is electrically connected with a charger module, and each charger module comprises an alternating current filter circuit (1), an AC/DC converter (2), a direct current bus capacitor (3), a DC/DC converter (4) and a direct current filter circuit (5) which are sequentially connected.

2. The high-power bidirectional charger according to claim 1, characterized in that an electromagnetic interference suppression module is connected between each winding of the multi-winding transformer (1-1) and the charger module.

3. The high-power bidirectional charger according to claim 1, characterized in that the AC/DC converter (2) is an ANPC three-level AC inverter circuit, a linear three-level AC inverter circuit, a T-shaped three-level AC inverter circuit, or a two-level AC inverter circuit.

4. The high-power bidirectional charger according to claim 1, characterized in that the DC/DC converter (4) adopts a three-phase interleaved Buck-boost circuit, a single-phase Buck-boost circuit, a four-phase interleaved Buck-boost circuit, a single-phase in-line three-level topology or a two-phase in-line three-level topology interleaved parallel circuit.

5. The high-power bidirectional charger according to claim 1, characterized in that the power devices in the AC/DC converter (2) and the DC/DC converter (4) are IGBTs, MOSFETs or MOSFETs of the silicon carbide type.

6. The high-power bidirectional charger according to claim 1, further comprising an AC sampling circuit (6), an AC driving circuit (7), a DC driving circuit (8), a DC sampling circuit (9) and a controller (10), wherein the AC sampling circuit (6) is configured to sample voltage, current and voltage signal at the DC side of the AC/DC converter (2), condition the collected voltage, current and voltage signal at the DC side and transmit the conditioned signals to the controller (10), and the controller (10) generates a control signal according to a control requirement and the received voltage, current and voltage signal at the DC bus side; the alternating current driving circuit (7) is used for transmitting a control signal of the controller (10) to a gate electrode of a power device in the AC/DC converter (2) after being isolated and amplified so as to control the output voltage and current of the AC/DC converter (2); the direct current sampling circuit (9) is used for collecting the inductive current and the battery side voltage signal of the direct current filter circuit (5) and transmitting the collected signals to the controller (10), and the controller (10) generates control signals according to control requirements and the received direct current inductive current and battery side voltage signals; the direct current driving circuit (8) is connected with the controller (10) and the DC/DC converter (4) and is used for transmitting a control signal of the controller (10) to a gate electrode of a power device in the DC/DC converter (4) after being isolated and amplified so as to control the output voltage and current of the DC/DC converter (4).