[introduction] inserting electric type electric car (in PEV) system, charger can divide for 3 level: AC Level 1 (<1.92 KW) , AC Level 2 (<19.2 KW) and DC Level 3 (>19.2 KW) . 1 as a result of its bulk and weight, do not suggest to be in high power uses a car to carry charger in 3 class system.

Inserting electric type electric car (in PEV) system, charger can divide for 3 level: AC Level 1 (<1.92 KW) , AC Level 2 (<19.2 KW) and DC Level 3 (>19.2 KW) . 1 as a result of its bulk and weight, do not suggest to be in high power uses a car to carry charger in 3 class system.

The article is not what be as high as 22 KW for power Che Zaifei to keep apart type to shed fast charger to put forward two kinds of develop to attack continuously structure. The typical module plan of this charger includes an AC/DC rectifier form, it is converter of a DC/DC next. AC/DC class is used normally single-phase or three-phase application will come true, specific depend on requirement of electrified wire netting. Three-phase option provided the benefit that shares identical hardware for interface of electrified wire netting and DC/DC class. Herein is read textual.

Leakage current

Leakage current dispute keeps apart the typical issue that dc fills quickly. Graph the way that 1 medium red line represents to leakage current can have shed ground of electrified wire netting and EV batholith. 2, a of 3 this problems common solution is to introduce segregation type transformer (power source changes course) . However, with blame segregation type develop attacks to be compared, the cost that isolates type system should be gotten high much, volume is heavier also / bigger. In addition, transformer can cause additional power loss, reduce efficiency thereby.

Graph 1: EV charges the leakage current method in the system

According to IEC 61851-1 standard, electric car charger not requisition transformer, 4 if unit of odd electric current is included in electric car system (RCD) , criterion need not additional electric segregation. Be based on afore-mentioned elements, the proposal uses blame segregation type to shed fast charger to solve leakage current problem continuously, and need not use additional transformer.

Charger configuration

Offerred charger solution accords with international (IEC) and United States (IEEE, NEMA) standard. To IEC standard, power source voltage is 240 V or 400 V (three-phase) , circuit frequency is 50 Hz. In the dc charger of the proposal, choice 390 V and 650 V regard dc as bus.

Arm of basic two class switch, Supper and Slower, and the charger that LC filter made a proposal. In view of its tall rated electric current is mixed voltage, wolfspeed C2M0025120D SiC MOSFET is chosen to be the main switch of circuit. Considering the power level that charges quickly 3 requirements are mixed the rated electric current of equipment, chose electric current of arm of 32A Rms rated switch for side of interface of electrified wire netting. Below one explained the choice is rated electric current is worth (the fundamental of 32 A Rms) .

The place on put together is narrated, two-way blame keeps apart 2 class to shed the design of fast charger to be based on the configuration option that the graph shows 2 times all the time continuously.

Graph 2: Fast dc charger configures option

Develop attacks structure

Charge in the light of what what put forward the solution introduced single-phase with three-phase two kinds of develop attack structure.

Attack to single-phase develop, can use a figure 3 medium formula decide phase current, among them U Grid, I Grid and α are single-phase voltage, electric current and power factor respectively. According to this equality, below the case that gives power demand and voltage of electrified wire netting, can calculate a needs electricity.

Graph 3: The phase current that single-phase develop attacks is calculated

Corresponding develop attacks the structure is shown 4 times like the graph.

Two switch arm forms commutator of a complete bridge in AC/DC side combination. DC/DC converter needs arm of a switch to be able to provide direct current source for batteries only (8 KW) .

Graph 4: Be not the develop that keeps apart single-phase charger to attack structure

As similar as before one kind of circumstance, when power rate and voltage of electrified wire netting are foregone, can decide phase current, if pursue,5 are shown. The gross that can evaluate shunt-wound switch arm next (32 A Rms) .

Graph 5: The powermeter that three-phase develop attacks calculates

In the graph 6 in, showed relevant develop attacks structure. The communication that 3 switch arm makes three-phase commutator / dc side. Paralell connection of 3 switch arm is used at DC/DC converter to provide direct current source for batteries (22 KW) .

Graph 6: The develop that is not charger of segregation type three-phase attacks structure

Can see, AC/DC and DC/DC converter share same dc bus bar.

Hardware design

Experimental hardware divides composition by the following ministry:

Three-phase inverter board, be based on capacitor of bus line of dc of driver of grid of 6 6 C2M0025120D SiC MOSFET, CRD-001, nine (B32774D8505K) and sensor of a volts d.c. (RP1215D)

Package board, be based on nine three-phase capacitor (B32774D8126K000, f of 12 μ ) , 3 voltage sensor (RP1215D) , sensor of 3 electric current (CKSR 25-NP) with 3 power relay (T9SV1K15-12)

Three-phase plane inductor, fast charger applies and design to be not segregation type only

Small controller: TMS320F28377S MCU is used at generating PWM signal for AC/DC converter and DC/DC converter.

Protector: To sever the link between output and batteries automatically, breaker of a dc was installed between batteries itself and DC/DC converter (M9U21240) . Between interface of electrified wire netting and AC/DC converter, joined a breaker (F204A-63/0.03) and RCD (M9F22463) . Communication breaker will prevent the alternating current that flows between electrified wire netting and interface to had produced electricity. If leakage of electricity of electrified wire netting exceeds threshold value, RCD can detect and disconnect the join of electrified wire netting and inverter.

The symmetrical circuit sketch map of AC/DC side is shown 7 times like the graph. Inverter board and component board is separated by high-pressured area, the distance is 8 Mm, offer 800-V segregation.

Graph 7: Sketch map of charger of three-phase of side of electrified wire netting

Besides hardware protection, software protection is used at be being banned when occurrence accident circumstance to use charger.

The develop of the proposal attacks structural advantage

Two kinds of blame that put forward keep apart develop to attack do not have transformer, this decreased to charge greatly systematic space and weight. All component can be placed in 200-mm of × of 400 of × of a 450 in enclosing, and the density of 0.6 KW/L power of estimation is showing prep above what compete on the market at present is fast charge equipment.

Compare with independent charger, the develop that puts forward has plumped the loss that eliminates transformer to cause will improve efficiency. Graph the 8 assessment that showed DC/DC changes course efficiency.

Graph 8: Via the DC/DC class efficiency of the test

Peak value efficiency is achieved 99.3% , and when rated power is 22kW, peak value efficiency is 98.8% . The average efficiency below rated power is 98.5% . Control of 0 foreword electric current can avoid leakage current, because the public site of net side capacitor is connected,receive dc bus bar. Leak electric current will is in by limitation requirement of more low-level contented standard.

(provenance: Powerelectronicsnews)

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