Patent Application
20230322098
The invention belongs to the technical field of electric vehicle charging, and particularly relates to a high-efficiency electrical topology of an integrated DC charging station and an operation control method thereof.
An existing DC charging station for electric vehicles is mainly composed of a plurality of DC charging piles. In order to meet the charging safety requirements, a high-frequency electrical isolation method is preferably used in the DC charging pile for high-frequency isolation between a DC bus on a supply side and a DC, bus on a charging side.
At present, high-frequency DC isolation is realized by installing isolation DC/DC modules between the DC bus on the supply side and the DC bus on the charging side. There are mainly two types of electrical topologies. One is, that the isolation DC/DC modules are installed in the DC charging piles respectively, which saves the floor space of the DC charging station, but the isolation DC/DC modules cannot be shared by the charging piles, and the isolation capacity of the charging pile is fixed. The other way is that all the isolation DC/DC modules are installed together and connected to each charging pile by changeable electrical connection; and although the capacities of the isolation DC/DC modules can be shared by the charging piles, this installation method requires an independent station building to install the isolation DC/DC modules and wiring between the isolation modules and the charging piles is complicated.
Therefore, an electrical topology which not only allows the isolation DC/DC modules to be installed in the DC charging piles respectively to save the building area, but also allows the capacities of these isolation DC/DC modules to be shared by the DC charging piles is of, great value.
Purpose of the Invention: To allow the isolation capacity to be shared by DC charging piles in a DC charging station, the invention provides an electrical topology of an integrated DC charging station and an operation control method thereof.
Technical Scheme: An electrical topology of an integrated DC charging station comprises a supply side DC bus connected to a DC source, K discrete charging pile units and a mutual aid total DC bus;
each charging pile unit comprises an input DC bus, a mutual aid sub-DC bus, an output DC bus, N isolation branches, a non-isolation DC/DC module and, an output terminal, the input DC bus of each charging pile unit is connected to the supply side DC bus, and the mutual aid sub-DC bus of each charging pile unit is connected to the mutual aid total DC bus;
the isolation branches have a same configuration, comprising an isolation DC/DC module, an output switch and a mutual aid switch;
in each isolation branch, an input side of the isolation DC/DC module is connected to the input DC bus, an output side is connected to the output DC bus through the output switch to form an output branch, and the output side is connected to the mutual aid sub-DC bus through the mutual aid switch to form a mutual, aid branch; the mutual aid sub-DC bus is connected to the output DC bus through a switch, and the output DC bus is connected to the output terminal through the non-isolation DC/DC module; and
when all the output branches of a charging pile unit connected to an electric vehicle are started and output power cannot meet required power of the electric vehicle, the mutual aid branches of other charging pile units are started to meet the required power of the electric vehicle.
Further, the DC source is a DC distribution network feeder or a DC side feeder of an AC/DC module of the charging station.
Further, a rated current I11 of the supply side DC bus is greater than or equal to a rated current of the DC source.
Further, a rated current I12 of the mutual aid total DC bus satisfies:
I12≥I11/U12, where U11 is a rated voltage of the supply side DC bus and U12 is a rated voltage of the mutual aid total DC bus.
Further, a rated current of each output switch and mutual aid switch is greater than or equal to a rated current I32 of an output side of the isolation DC/DC module.
Further, the rated current I32 of the output side of each isolation DC/DC module satisfies: I32=I21×U11/(U12×N), where I21 is a rated current of the input DC bus, I21=I11/K, U11 is a rated voltage of the supply side DC bus, and I11 is a rated current of the supply side DC bus; and
the rated current I23 of each output DC bus satisfies: I23≥I32×N+I22; where I22 is a rated current of the mutual aid sub-DC bus.
Further, a rated voltage U42 and a rated current I42 of an output side of each non-isolation DC/DC module satisfy: U42×I42≥U12×I22×r, where U12 is a rated voltage of the mutual aid total DC bus, I22 is a rated current of the mutual aid sub-DC bus, and r is a coincidence factor.
The invention further discloses an operation control method of the electrical topology of an integrated DC charging station described above, comprising:
when the integrated DC charging station runs normally, all output switches and mutual aid switches being off, and all isolation DC/DC modules and non-isolation DC/DC modules not working;
when a current charging pile unit is connected to, an electric vehicle, the following steps being performed:
step 1, assuming that the required power of the electric vehicle is Pv,
determining whether Pv is greater than I32×N;
if Pv is greater than I32×N, determining whether the number d of isolation DC/DC modules in an idle state in other charging pile units satisfies:
(Pv/U12−I32×N)≤d×I32; if so, proceeding to step 2; if not, that is,
(Pv/U12−I32×N)>d×I32, proceeding to step 3;
if Pv is less than or equal to I32×N, starting b isolation DC/DC modules in the current charging pile unit, closing an output switch connected to the b started isolation DC/DC modules, and starting the non-isolation DC/DC module of the current charging pile unit so that the current charging pile unit outputs the required power of the electric vehicle, where b satisfies: (b−1)×I32<Pv/U12≤b×I32;
step 2, starting N isolation DC/DC modules in the current charging pile unit, closing an output switch connected to the N started isolation DC/DC modules, and starting the non-isolation DC/DC module of the current charging pile unit; meanwhile, starting c isolation DC/DC modules in an idle state in other charging pile units, c satisfies: (c−1)×I32<(Pv/U12−I32×N)≤c×I32, and closing a mutual aid switch connected to the c started isolation DC/DC modules so that the current charging pile unit outputs the required power of the electric vehicle; and
step 3, starting N isolation DC/DC modules in the current charging pile unit, closing an output switch connected to the isolation DC/DC modules, and starting the non-isolation DC/DC module of the current charging pile unit; meanwhile, starting d isolation DC/DC modules in an idle state in other charging pile units, and closing a mutual aid switch connected to the d isolation DC/DC modules so that the current charging pile unit outputs a power smaller than the required power of the electric vehicle.
Beneficial Effects: Compared with the prior art, the invention has the following beneficial effects:
The technical scheme of the invention will be further explained with reference to the drawings and embodiments.
As shown in
The charging pile units have a same configuration. The first charging pile unit comprises an input DC bus 2161, a mutual aid sub-DC bus 2162, an output DC bus 2163, N isolation DC/DC modules (2111-211N in
The input DC bus of each charging pile unit is connected to the supply side DC bus 1001, that is, the input DC bus 2161 of the first charging pile unit, the input DC bus 2261 of the second charging pile unit . . . the input DC bus 2K61 of the Kth charging pile unit are all connected to the supply side DC bus 1001. The mutual aid sub-DC bus of each charging pile unit is connected to the mutual aid total DC bus 1002, that is, the mutual aid sub-DC bus 2162 of the first charging pile unit, the mutual aid sub-DC bus 2262 of the second charging pile unit . .. the mutual aid sub-DC bus 2K62 of the Kth charging pile unit are all connected to the mutual aid total DC bus 1002.
An internal topology of the charging pile unit of the invention will be explained in detail by taking the first charging pile unit as an example. The input DC bus 2161 is connected to input sides of the N isolation DC/DC modules (2111-211N in
The capacity configuration principle of the electrical topology of an integrated
DC charging station with the above structure is explained below.
The charging process of an electric vehicle using DC charging piles is mainly divided into three stages: constant-current charging, constant-voltage charging and trickle charging. The charging power gradually increases and then decreases, and the required power is much lower than the maximum power in most of the charging process.
Therefore, the rated working voltage and insulation and voltage resistance of all components in, the electrical topology of an integrated DC charging station of the invention should be greater than the requirements of relevant standards. Specifically,
a rated voltage of the supply side DC bus 1001 is U11, a rated current is I11, I11 is greater than or equal to a rated current of a superior DC distribution network feeder or a DC side feeder of an AC/DC module of the charging station, a rated voltage of the mutual aid total DC bus 1002 is U12 a rated current is I12, and I12 satisfies: I12≥I11×U11/U12.
A rated voltage of each input DC bus (2161-2K61 in
The invention also discloses an operation control method of an integrated DC charging station.
During operation, all output switches and mutual aid switches are off, and isolation DC/DC modules and non-isolation DC/DC modules are not working.
When a current charging pile unit is connected to an electric vehicle, the following steps are performed:
step 1, assuming that the required power of the electric vehicle is Pv,
determining whether Pv is greater than I32×N;
if Pv is greater than I32×N, determining whether the number of isolation DC/DC modules in an idle state in other charging pile units satisfies:
(Pv/U12−I32×N)≤d×I32; if so, proceeding to step 2; if not, that is,
(Pv/U12−I32×N)>×I32, proceeding to step 3;
if Pv is less than or equal to I32×N, starting b isolation DC/DC modules in the current charging pile unit, closing an output switch connected to the b started isolation DC/DC modules, and starting the non-isolation DC/DC module of the current charging pile unit so that the current charging pile unit outputs the required power of the electric vehicle, where b satisfies: (b−1)×I32<Pv/U12≤b×I32;
step 2, starting N isolation DC/DC modules in the current charging pile unit, closing an output switch connected to the N started isolation DC/DC modules, and starting the non-isolation DC/DC module of the current charging pile unit; meanwhile, starting c isolation DC/DC modules in an idle state in other charging pile units, c satisfies: (c−1)×I32<(Pv/U12−I32×N)≤c×I32, and closing a mutual aid switch connected to, the c started isolation DC/DC modules so that the current charging pile unit outputs the required power of the electric vehicle; and
step 3, starting N isolation DC/DC modules in the current charging pile unit, closing an output switch connected to the isolation DC/DC modules, and starting the non-isolation DC/DC module of the current charging pile unit; meanwhile, starting d isolation DC/DC modules in an idle state in other charging pile units, and closing a mutual aid switch connected to the d isolation DC/DC modules so that the current charging pile unit outputs a power smaller than the required power of the electric vehicle.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202011618136.0 | Dec 2020 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2021/104273 | 7/2/2021 | WO |
