The power system in a modern electric vehicle has two important components: The electric motor, and the controller. The electric motor feeds power from the batteries to convert electrical energy into mechanical energy. On the other hand, the controller is responsible for literally ‘controlling’ or regulating how the electric motor’s power is applied to produce forward motion.
You can think of controllers as the carburetor in an older engine. The carburetor combines the right fuel and air mixture to control a vehicle’s speed and acceleration as you press on the accelerator pedal. The controller in an electric vehicle works in the same principle. But instead of mixing fuel and air, EV controllers regulate the flow of energy from the battery by analyzing the pulse width modulation of the power system.
Determining the right type of EV controller depends on many factors, but it has mainly to do with the type of electric motor. There are two main types of electric motors for vehicle applications: The DC or direct current motor, and the AC or alternating current motor. Earlier models of electric cars are equipped with a DC motor and controller to reduce developmental and manufacturing costs. True to form, the combination of a DC motor and controller is more cost-efficient, but there are drawbacks. For starters, DC motors and controllers are heavier and less efficient than an AC motor.
On the other hand, the AC motor is lighter, cheaper, more compact, and more reliable. Hence, a large majority of modern electric vehicles – including Tesla – have AC motors. However, AC motors require complex and more expensive controllers to get the job done. In an AC motor, the controller not only operates as a ‘floodgate’ between the motor and battery pack, but it also transforms the DC current from the battery into AC current for the motor. EV controllers are also responsible for reversing the rotation of the motor (when the vehicle is backing up or moving in reverse).
More importantly, controllers allow the engine to function as a generator to recharge the batteries. In regenerative mode, the controller converts the kinetic energy of the spinning wheels to feed the battery pack, and it happens instantly and simultaneously when cruising or pressing the brake pedal.
The simplest and most common type of controller is the variable-resistor-type controller, most commonly found in older EVs with DC motors. With this system, the controller draws full current from the battery, while a resistor is used to reduce the current at slower vehicle speeds. Modern EVS have more advanced controllers equipped with silicone rectifiers that analyze the pulse width modulation of the EV power system. Controllers for AC motors work by rapidly switching the flow of electricity on and off to offer a forward motion or regenerative braking depending on how the pulse signal is analyzed.
Cloud Electric has a wide inventory of controllers for both DC and AC motors from the most trusted brands like Curtis, General Electric, Yamaha, Toyota, Crown, Genie, Nissan/Hitachi, Cat/Mit/Daewoo, RoboPac, Kalmar AC, Jungheinrich, Navitas, Parker, and many more.