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Introduction
The development of Charging station infrastructure plays a major role in the development of the EV ecosystem. The Committee on standardization of protocol for Electric Vehicles (EV) Charging Infrastructure has come out with recommendations entailing specifications for AC and DC charging for electric vehicles. These standards are called – Bharat EV Charger AC-001 and Bharat EV Charger DC-001. India will deploy both CHAdeMO and Combined Charging System (CCS) fast-charging technologies, besides the existing Bharat Standard, at its public electric vehicle charging stations.
Bharat Standards
Home Charging
The home private chargers are generally used with 230V/15A single phase plug which can deliver a maximum of up to about 2.5KW of power. Thus, the vehicles can be charged only up to this rate. The billing for power is part of home-metering. This will be continued till a policy evolves to charge the home users differently for EV use. Also, Bharat EV Specs recommends using the IEC 60309 Industrial connector from both ends.
Public Charging
For charging outside the home premises, Bharat EV standards recommend that the electric power needs to be billed and payment needs to be collected. The power utilities may also want to manage power drawn by these chargers from time to time.
DC Charging
General Requirements
The method for charging an EV is to use an off-board charger for delivering direct current. The EV shall be connected to the EVSE so that in normal conditions of use, the conductive energy transfer function operates safely.
- Energy transfer mode: Conductive
- EVSE type: Dual-connector DC EVSE
- No. of outputs: 2
- Charging mode: Mode 4 – DC Charging [DC charging is defined as Mode 4 as per IEC61851-1 section6.2]
System Structure
The System requirement parameters are derived from Table D1 of Annex DD of IEC 61851-23.
- Regulation: Regulated DC EV Charging station with a combination of the modes: controlled voltage charging (CVC) and controlled current charging (CCC)
- Isolation: Isolated DC EV charging station, according to the type of insulation between input and output: a) Basic insulation, b) Reinforced insulation, c) Double insulation
- Each DC output should be isolated from each other [Section 7.5.101 of IEC 61851-23].
- Environmental conditions: Outdoor use. EVSEs classified for outdoor use can be used for indoor use, provided ventilation requirements are satisfied.
- Power supply: AC mains to DCEV charging station
- DC output voltage rating: Up to and including 100 V
- Charge control communication: Communicate by digital and analog signals
- Output Current: 200A
- Interface Inter-operability: Interoperable with any EV (non-dedicated, can be used by any consumer).
- Operator: Operated by a trained operator or EV owner
Input Requirements
Rating of the AC supply voltage
- The AC supply system would be 3-Phase, 5 Wire AC system (3Ph+N+E) Nominal Input Voltage is 415V (+6% and -10%) as per IS 12360
- The Rated value of the frequency is 50 Hz ± 1.5Hz.
Battery back-up
The Input supply system to have a battery backup for a minimum of 1 hour for the control and billing unit. The data logs should be synced with CMS during back-up time, in case the battery drains out.
Output Requirements
The Charger can provide two DC outputs suitable for 48V and 72V vehicle battery configurations.
There can be two categories of chargers based on the limit on the output power of the chargers as shown in Figure below.
The chargers should allow charging of one vehicle with maximum power (10 kW or 15 kW) or 2W vehicle with limited power (3.3 kW at 48V only) as per the output configurations types given in section 3.4.1
- DC Output voltage: 48V or 72 V
- Output current: limited to 200A
- Converter Efficiency: > 92% at nominal output power
- Power factor: > 0.90 (Full Load)
Charger Configuration Types
- Type 1: Single vehicle charging at 48V or 72V with a maximum of 10kW power, or a 2W vehicle charging at 48V with a maximum power of 3.3 kW.
- Type 2: Single vehicle charging at 48V with a maximum of 10kW power or 72V with a maximum of 15 kW power or a 2W vehicle charging at 48V with a maximum power of 3.3 kW.
Output Connector Requirements
- Number of Outputs: 2 outputs
- Output 1: to be used for 10 kW or 15 kW charging, Connector is GB/T20234.3. The Connector details are provided in Annex B1
- Output 2: connector to be used for 3.3 kW charging will be defined in due course of time.
Cable Requirements
- Charging Cable Assembly: As per Section 10 of AIS 138 Part 1, except the functional characteristics defined as below
- Functional characteristics: The maximum cord length will be 5 meters, straight cable
- Cable Connection Type: supply cable will be with EVSE as per Case C defined in section
- Cord Extension Set: No extension cord to be used, as per Section 6.3.1. of AIS 138 Part 1
- Adaptors: No adapters to be used as per Section 6.3.2 of AIS 138 Part 1
- Storage means of the cable assembly and vehicle connector: EVSE should have storage for cable and connector when not in use, at a height between 0.4m to 1.5m above ground level, as per IEC 61851-23 Section 101.1.3
Functional Requirements
The functional requirements should be as per Section 6.4.3 of IEC 61851-1 and Section 6.4.3 of IEC 61851-23 except for the following functions, to be implemented as follows.
Measuring current and voltage: The accuracy of output measurement of system B shall be within the following values:
- Voltage measurement: ± 0,5%
- Current measurement: ±1 A if the actual current is less than or equal to (≤) 50 A
Protection against overvoltage at the battery: The DC EV charging station shall reduce the DC output current to less than 5 A within 2 s, to prevent overvoltage at the battery, if the output voltage exceeds the maximum voltage limit of the battery system for 1 s
Communications
The Bharat EV Specifications also discusses the communications that need to occur between the EVSE and an electric vehicle. Also, the communication that needs to happen between the EVSE and a remote server.
- The EVSE needs to communicate with BMS of the battery pack in the EV, to enable it to charge at the right rate for maintaining SOC of batteries. The physical layer for this communication will be CAN, as it is commonly used by vehicle manufacturers in India.
- Communication between EVSE and Central management system (CMS) located at the power utility company, so as to enable the maximum charging rate to be controlled depending upon the rates of grid supply. This will also enable metering at different rates. This is critical as whenever vehicles consume large currents and the grid should be able to supply it. This will also enable the reservation of chargers by users.
- The communication protocol used will be OCPP. This will be carried on the Internet, using wired media or wireless (Wi-Fi or GPRS or 3g/4g wireless).
DC001 Specification Summary
| Sl.NO | Parameter | Description | |
| General Requirements | |||
| 1 | EVSE Type | Dual-connector DC EVSE | |
| 2 | Energy Transfer Mode | Conductive | |
| 3 | Charging mode | Mode 4 | |
| 7 | Reliability and Serviceability | Modularity, self-diagnostic features, fault codes and easy serviceability in the field | |
| System Structure | |||
| 1 | Regulation Method | Regulated d.c EV charging station with a combination of CVC or CCC but not simultaneously | |
| 2 | Isolation | Each output isolated from each other with proper insulation | |
| 3 | Environmental conditions | Outdoor use | |
| 4 | Power supply | DC EV charging station connected to AC mains | |
| 5 | DC output voltage rating | Up to and including 100 V | |
| 6 | Charge control communication | Communicate by digital and analog signals | |
| 7 | Interface inter-operability | Inter-operable with any EV(non-dedicated, can be used by any consumer) | |
| 8 | Operator | Operated by a trained person or EV Owner | |
| Input Requirements | |||
| 1 | AC Supply System | 3-Phase, 5 Wire AC system (3Ph+N+E) | |
| 2 | Nominal Input voltage | 3Ø, 415V (+6% and -10%) as per IS 12360 | |
| 3 | Input Frequency | 50Hz, ±1.5Hz | |
| 4 | Supply-side AC Connector forInput | IEC 62196 Type 2 as per Annex 1 | |
| 5 | Input Supply Failure backup | Battery backup for a minimum of 1 hour for the control system and billing unit, to enable activities such as billing, to be provided. | |
| Output Requirements | |||
| 1 | Output Details | Suitable for 48V and 72V vehicle battery configuration | |
| 2 | Charger Configuration Types | i. Type 1: Single vehicle charging at 48V or 72V with a maximum of 10kW power, or a 2W vehicle charging at 48V with a maximum power of 3.3 kW.ii. Type 2: Single vehicle charging at 48V with a maximum of 10kW power or 72V with a maximum of 15 kW power or a 2W vehicle charging at 48V with a maximum power of 3.3 kW. | |
| 3 | Output Current | 200 Amp Max | |
| 4 | Number of Outputs | 2 | |
| 5 | Output Connectors | 2 output connectors | |
| 6 | Output Connector Compatibility | one connector with GB/T 20234.3 as per Annex 1 + 1 connectors to be defined | |
| 7 | Converter Efficiency | > 92 % at nominal output power | |
| 8 | Power factor | ≥ 0.90 (Full load) | |
| Cable Requirements | |||
| 1 | Charging Cable Length | 5 Meter, Straight Cable | |
| 2 | Cable Type | Charging cable and connector permanently attachedto DC FC | |
| Environmental Requirements | |||
| 1 | Ambient Temperature Range | 0°C to 55°C | |
| 2 | Ambient Humidity | 5 to 95% | |
| 3 | Ambient Pressure | 86 kpa to 106 kpa | |
| 4 | Storage Temperature | 0 to 60°C | |
| Mechanical Requirements | |||
| 1 | Ingress Protection | IP 54 | |
| 2 | Mechanical Stability | Shall not be damaged by mechanical impact as defined in Section 11.11.2 of IEC 61851-1 | |
| 3 | Cooling | Air Cooled | |
| 4 | Mechanical Impact | Shall not be damaged by mechanical impact as defined in Section 11.11.3 of IEC 61851-1 | |
| 5 | Dimension(W*H*D)/Weight | To be decided e.g W*H*D mm, xxx Kg | |
| User Interface & Display Requirements | |||
| 1 | ON- OFF (Start-Stop) switches | Simple Push button type | |
| 2 | Emergency stop switch | Simple Push button type in Red Color | |
| 3 | Visual Indicators | Error indication, Presence of input supply indication, State of charge process indication | |
| 4 | Display | Minimum 6 inches with 720 x 480 pixels TFT LCDTouch Screen | |
| 5 | Support Language | English | |
| 5 | Display Messages | EVSE should display appropriate messages for the user during the various charging states like• Vehicle plugged in / Vehicle plugged out• Duration since start of charge, Time to charge, kWh.• User authorization status• Idle / Charging in progress: SOC• Fault conditions• Metering Information: Consumption Units | |
| 7 | Authentication | As per OCPP (through a mobile application or cardreader) | |
| Performance Requirements | |||
| 1 | DC Output voltage and current tolerance | DC Output current regulation in Constant Current Charging (CCC):± 2.5 A for the requirement below 50 A, and ± 5 % of the required value for 50 A or moreDC Output voltage regulation in Constant Voltage Charging (CVC): Max. 2 % for the max rated voltage of the EVSE | |
| 2 | Control delay of charging current in CCC | DC output current Demand Response Time: <1 s Ramp up rate: 20 A/s or more Ramp Down rate: 100 A/s or more | |
| 3 | Descending rate of charging current | EVSE should be able to reduce DC current with the descending rate of 100 A/s or more | |
| 4 | Periodic and random deviation (current ripple) | DC output current ripple limit of EVSE:1.5 A below 10 Hz, 6 A below 5kHz, 9A below 150 kHz | |
| 5 | Periodic and random deviation (voltage ripple) | Max. ripple voltage: ±5 V. Max slew rate: ±20 V/ms | |
| Communication Requirements | |||
| 1 | Communication between EVSE and Vehicle | CAN-based as per IEC 61851-24 Annex 3 | |
| 2 | Communication interface between charger and central management system(CMS) | Ethernet(Standard), Wi-Fi | |
| 3 | Communication between EVSE and Central Server | Open Charge Point Protocol (OCPP) 1.5 protocol. Should be upgradable to next version of OCPP whenever it is released including OCPP2.0 which is a draft version nowIt should enable handshaking between EVSE and CMS for discovery. It should authorize the operation before electric vehicles can start or stop charging. EVSE should respond to CMS for various queries and commands like reservation, cancellation. Metering: Grid responsive metering | |
| Billing Requirements | |||
| 1 | Billing | Grid responsive metering | |
| 2 | Payment | BHIM and Bharat QR compliant mobile application payment | |
| Protection & Safety Requirements | |||
| 1 | Safety Parameters | Over current, under voltage, over voltage, Residual current, Surge protection, Short circuit, Earth fault at input and output, Input phase reversal, Prevention of vehicle movement during charging, Emergency shut- down with alarm, Over temperature, Protection against electric shock | |
Bharat DC001 Specifications
Know more on the EV charging ecosystem in India from: Components of EVSE | Bharath DC001 | Bharat AC001 | EVSE Growth Trends | Battery Swapping Growth Trends | EVSE Cost components | EVSE installation costs | Battery swapping in India | Indian EVSE Stakeholders | Charger Standards | Current Indian EVSE status | EVSE Challenges | EVSE during 2020-2030 |
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