Some people who wanna buy a product would do a bit of research on the specifics of the product. An EV Charger is no different, a spec sheet sure tells a lot but they don’t tell what’s under the hood of an EV Charger that actually does the charging or helps with the process. So here’s a quick analysis of some of the components within an EV Charger.

Stage 1: Power Input Stage

AC Mains (230V) → Surge Protector → EMI Filter → Contactor

Malaysian electrical phase systems for the majority use single phase 230V/50hz. The first of many processes involves regulating the power received throughout the household electrical system and towards the Level 2 Home EV Charger.

Unlike a DC Fast Charger an AC Charger does not require the needs of a rectifier to convert AC to DC for the charging as your EV already has built-in-rectifiers that convert typically from 3.3 kW to 22kW.

Surge Protection Device

The surge protection device diverts high voltage transients aka lightning strikes or electrical grid operations. These occur when there’s an unexpected increase within voltage that occurs in electrical systems.

An SPD monitors the voltage level from within the charging system and will divert the excess energy away from sensitive components. The energy is dissipated through proper channeling towards the ground.

EMI/RFI (Electromagnetic Interference & Radio Frequency Interference)

You’ve probably heard of noise-cancelling headphones before or even tried it on, it basically drowns or eliminates noise from the outside so you can get clear-cut audio from your headphones. Well the concept is similar here utilizing EMI/RFI. It blocks out high frequency noise from sensitive vehicle electronics while maintaining regulations. Ensures that safe and reliable energy is channeled towards your EV.

Contactor Relay

Relays and connectors are used to disconnect the cable from your EV in the event of a fault, problem or when the EV is at the end of its charge cycle. Breaking apart from the AC current load to the onboard EV charger is important. 

A larger relay than Level 1 charging is required as it is able to supply more current. Level 2 Chargers are required to break from both Live and Neutral simultaneously reducing risk of an error to occur if only a single conductor is disconnected , a double pole relay is ideal for this.

Stage 2: Communication and Control 

The EV Charger doesn’t immediately start charging once energized, it takes a few steps to identify and facilitate interaction between the vehicle and EV Charger.

Microcontroller

The microcontroller in short is the brains of the EV Charger. It manages charging logic, safety checks, user interface and serves as a medium to communicate between it and the EV’s battery management system. This checks if the connector is connected and ensure prevents power flow if the plug is half connected.

 It aids in controlling what's called a control pilot which sends a PWM signal to communicate with the EV. Safety is also made sure through ground continuity and faults within the insulation. All of the connectivity options are packed within this component that allows for smart charging features such as Wi-Fi,4G and Bluetooth.

Charging Controller

This is also implemented with the microcontroller at times but also exists as an independent integrated circuit. This is usually found in DC Fast Chargers. Its primary role is to regulate voltage as well as manage the parameters in charging the EV given from communication between the microcontroller and the EV. 

Power conversion is minimal as it happens on the EV’s onboard charger for AC EV Chargers. This handles the contactor relay control and monitors the thermals for the cable and connector.

Stage 3: Charging Safety

CT Clamp

This is an important component that serves to monitor real time of the current flowing through your home’s electrical system whilst charging. The CT clamp enables the EV Charger to respond accordingly if it detects any abnormal readings that exceed safe limits. This is similar to how our consumption of electricity is measured and billed towards us every month.

Smart charging management. The CT Clamps are used in the features such as load balancing by monitoring the total load and prevents your home’s electrical system being overloaded by decreasing the amount of power output to your EV.