Seite - 114 - in Hybrid Electric Vehicles

other methods where these transducers are eliminated (sensorless) exist. In these cases, the rotor position is estimated by using complex algorithms, using as input the measurement values of voltages and currents [29]. The general diagram control presented in Figure 7, usually used for PMSM and SynRM, can be divided into power and control components. The power circuit consists of the electrical machine (PMSM/SynRM), DC/DC converter, inverter, while the control loop consists of speed transducer, current transducers, PWM signal generation block, transformation of coordinate systems blocks and computing block of references current. The control strategies considered for the SynRM are: • Maximum torque control per ampere control (MPTAC) The model of control is based on imposing the same currents for the d and q axes of the machine as current references for the vector control of the machine. These currents are calcu- lated from the torque equation like i d   =  i q   =  √ _________ T ref _________p ⋅ ( L d     − L q) (2) • Maximum rate of change of torque control (MRCTC) The control strategy is implemented in order to obtain fast machine response at sudden torque steps of the load. The idea here is to compute the d and q current component functions of some machine parameters and to use these components as input of the vector control scheme. The detailed control strategy is presented in Ref. [30]. • Maximum power factor control (MPFC) The aim of this method is to maximize the power factor of the machine. For this, the d and q current components are computed as follows: I qimposed   =  T ref ⋅ 1 __p ⋅ 1 _____ L d − L q ⋅ 1 ___________ I d  (from the machine) (3) Figure 7. Block diagram of vector control system for PMSM and SynRM. Hybrid Electric Vehicles114