Importance

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Abstract

A vehicle system (10) is provided. The vehicle system comprises an electrical DC motor (11) driving a load (12), such as a hydraulic pump, and a control system (100) for controlling the speed of the electrical motor (11). The control system (100) comprises a system (20) for monitoring and controlling the speed of the electric DC motor in view of a reference commutation signal (S_R), wherein the electrical DC motor is associated with a drive current signal (I_D), and wherein the drive current signal (I_D) comprises information relating to the commutation signal of the electrical DC motor. The system (20) comprises a speed estimation unit (23) for estimating a commutation signal (S_E) from the drive current signal (I_D), said commutation signal (S_E) corresponding to an estimated motor speed; a filter unit (25) configured to apply a first filter on the drive current signal (I_D), said first filter being selected based on the estimated commutation signal (S_E), thereby resulting in a filtered drive current signal, and a speed detector unit (26) for detecting the actual commutation signal (S_M) from the filtered drive current signal. If the detection of the commutation signal (S_M) is unsuccessful the speed estimation unit (23) is based upon the receipt of a signal (S_M-NO) from the speed detector unit (26) configured to transmit an estimated commutation signal (S_E) to a control unit (28), wherein the control unit is configured to provide a control signal comprising information of a comparison between the reference commutation signal (S_R) and the estimated commutation signal (S_E) and indicating a required updated drive signal (I_D).

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First Claim