circuito de medição, circuito de controle de motor, combinação de um motor elétrico, sistema de direção auxiliado por energia elétrica, e, método para medir pelo menos uma posição rotacional e velocidade rotacional do rotor de um motor elétrico

摘要

A measurement circuit for measuring at least one of the rotational position and rotational speed of the rotor of an electric motor, typically such as may be used in an electric power assisted steering apparatus, the circuit comprising: first and second inputs for receiving first and second input signals which vary cyclically with the rotational position of the rotor, the first and second input signals at the first and second inputs varying in quadrature with each other; a phase detector circuit; and an observer circuit; in which the observer circuit is arranged to generate estimates indicative of the frequency and phase of the first and second input signals; in which the phase detector circuit is arranged to determine the phase difference between first and second estimated signals varying cyclically and at the frequency indicated by the estimates with a phase difference dependent on the phase difference indicated by the estimates, the first and second estimated signals varying in quadrature with each other on the one hand and the first and second input signals on the other by adding a multiplicative combination of the first input signal with the first estimated signal to a multiplicative combination of the second input signal with the second estimated signal to result in a sum signal dependent upon the phase difference; and in which the observer circuit is arranged to vary the estimates dependent upon the sum signal.