Production Test Stands for Electric Motors

Electric drives such as DC and EC motors are more and more extensively deployed in the automotive industry. At the same time there is an increasing requirement for a 100% analysis of motors for fault detection and error analysis as well as statistics on quality, without increasing production cycles times. The model-based Parameter Identification method (PI method) from imc allows testing to be performed under load, yet without an “explicit” separate load machine. Instead, the motor is loaded dynamically by exploiting its own inherent inertia. This allows motor parameters such as resistance, inductivity and friction to be determined within a few seconds. A mathematical model and its parameters reflect motor behaviour in its completeness and make it possible to monitor motor production based on limit values and trend statistics. The identified parameters of the model equation can then be used to calculate derived key performance indicators of the motor characteristic curve.

 

Innovative Test Methods

Recent years have seen a shift from DC motors to electrically commutated motors (EC motors) in critical and safety critical vehicle applications. The chosen motor should be optimally exploited, above all in terms of optimized efficiency for the required torque profile.

In this regard, several challenges need to be faced. Along with precisely determining the relationship between magnetic flux and current, the power electronics (ECU) must be programmed with the optimum control sequence based on the assessed flux ratios. If possible, this should be individually tailored to each motor specimen and its associated ECU unit. On top, all this should be accomplished with shorter test cycles and simple test processes and setups.

Test stands from imc achieve this by avoiding the classic design consisting of load machine, torque measuring shaft and coupling provisions. A model based approach to determining motor parameters using dynamic measurement data has taken its place.

Classic Design with Load machine

Model-based method

Other Test Stand Solutions from imc

imc Test & Measurement is an Axiometrix Solutions company.

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