Advertised vs. Actual Efficiency in Practice

AC induction motors are designed to operate at one “rated” speed and load, and the advertised efficiency of the motor is at that one particular speed and load. If the motor needs to be operated at any combination of speed and load other than the one for which it was designed (i.e. almost any real-world application), a piece of hardware called a motor drive is used.  When a drive is used to operate the motor at combinations of speed and load other than the one for which it was designed, the maximum possible efficiency declines–sometimes significantly.

While many electric motors or power trains are stated as being 90% efficient or better, this is only the case under those “rated” operating conditions (motor manufacturer’s rated speed and load). In practice, motors are invariably oversized for their application and underloaded.  Load and speed both vary.  Imagine an elevator or escalator as people enter and leave, or a pump operating as debris impedes it. In the case of EVs, the speed and load are always changing. And the theoretical efficiency of the motor under these different operating conditions is much lower than the advertised efficiency.

No drive can control a motor to exceed the maximum possible efficiency for a given speed and load, as this is a physical limitation of the design of the motor. However, the AC Kinetics software enables a drive to operate the motor as closely as possible to the maximum achievable efficiency in any operating condition, while improving dynamic performance. This is not accomplished by any of today’s leading drives.

The AC Kinetics software enables a drive to use the minimum amount of energy necessary to achieve any performance specification.  It delivers superior performance to today’s leading drives using much less energy than these drives consume, and it configures itself automatically. The software delivers the maximum amount of output power using the minimum amount of input energy.

Our hardware testing shows that the AC Kinetics drive solution outperforms today’s leading drives under all operating conditions, including steady state, and the more the speed and load varies, the better the AC Kinetics drive software performs relative to these other drives. On the EPA urban traffic cycle we tested, we used half of the energy of other drives, which would equate to increased range in an electric vehicle.  However, the actual increase in range will vary depending on the nature of the driving cycle.