A steering knuckle pin bearing assembly includes a bearing and a steering knuckle pin pivotably supporting a steering knuckle relative to an axle beam. The common support is so constructed as to enable mounting of the coolant reservoir and pump in any selected one of a number of different locations. , an influence of a deviation of the axis of an alternating current due to a rotor magnetic pole position \u03b8 on the estimation of a magnetic pole position, is eliminated, and, in particular, the magnetic pole position of a double saliency electric motor can be estimated with high precision. A controller can generate an output force signal in response to the input voltage signal to help cancel the input voltage signal.