HEV/EV System

Shown in the following are the block diagrams of a hybrid electric vehicle (HEV), an electric vehicle (EV) and a plug-in hybrid electric vehicle (PHEV).

A hybrid electric vehicle (HEV) combines the advantages of an electric motor and an internal combustion engine (ICE).
HEVs are primarily driven by an electric motor whenever an ICE is not as efficient as an electric motor and otherwise run on the ICE.
During braking, the electric motor works as a generator and recharges a battery by converting the vehicle kinetic energy into electric energy.
HEVs can use a smaller drive battery pack than EVs because HEVs rely less on an electric motor.

Click the "Inverter" and "DC-DC Converter" boxes below to jump to their descriptions.

An electric vehicle (EV) uses an electric motor(s) for propulsion in lieu of an internal combustion engine.
EVs do not use fossil fuel; instead they are 100% powered by electric energy stored in on-board battery packs.
During braking, the electric motor works as a generator and recharges the battery by converting the vehicle kinetic energy into electric energy.
There are two types of drivetrain design: one in which an electric motor simply replaces an internal combustion engine, and one that uses in-wheel motors, or motors housed directly in each wheel.

Click the "Inverter" and "DC-DC Converter" boxes below to jump to their descriptions.

A plug-in hybrid vehicle (PHEV) shares the characteristics of both an electric vehicle and a conventional hybrid vehicle.
A PHEV has a large, high-capacity battery pack and thus much longer all-electric driving range.
A PHEV normally runs on electric power; the combustion engine works as a backup when the battery runs short.

Click the "Inverter" and "DC-DC Converter" boxes below to jump to their descriptions.

Generally, EVs and HEVs use three-phase brushless motors for electric propulsion.
Because the vehicle drive battery supplies a dc current, it needs to be converted to a three-phase ac current. An inverter is used for this purpose.
A three-phase inverter, which is composed of power devices, converts dc to ac during acceleration (powering) and converts ac to dc during braking (regeneration).

• An MCU receives commands via the CAN bus and controls motors by means of an inverter (Motor 1 and Motor 2 in the above figure).
• Offers an A-PMD(*1), which features a Vector Engine, an RDC(*2) and one-shot pulse control, to generate PWM signals for the purpose of accurately controlling the drive current for three-phase motors on an HEV or EV for improved efficiency.
• Functional safety (IEC61508/ISO26262-compliance)
  (Technology certified by TÜV -SÜD Automotive)

*1：A-PMD / Advanced Programmable Motor Driver

*2：RDC / Resolver to Digital Converter

Vehicles driven by electric motors can generate electricity using an internal combustion engine or during braking. This eliminates the need for an alternator that has been equipped in conventional automobiles.
The electric power generated by a vehicle drive motor and stored in a battery pack has a high voltage (usually over 100 V). It needs to be converted to the typical battery voltage for accessories (either 12 V or 24 V). A DC-DC converter is used for this purpose.