Predictive Control of Power Converters and Electrical Drives

5.6 Summary

The predictive current control method presented does not require any kind of linear controller or modulation technique. It effectively controls the load current and compares well to established control methods like PWM, achieves a comparable dynamic response and reference tracking, and works at lower switching frequencies. If both methods are compared at the same switching frequency, as presented in Table 5.2, the predictive strategy reveals a lower tracking error. In addition, the proposed method shows no interaction between both components of the load current.

One of the remarkable aspects of the method is the use of costs assigned to each objective to achieve reference tracking, balance in the DC link, and a reduction in the switching frequency. The simplicity of the theory makes it easy to understand and implement. The strategy allows the designer to adjust the λ parameters to fit the requirements in terms of switching frequency, voltage balance, and reference tracking. A systematic way to determine the weighting factors is a challenge for future work. Some guidelines on the adjustment of these parameters are given in Chapter 11.

The method can be easily implemented by taking advantage of the present technologies available for DSPs. The higher sampling frequencies required should not be a problem nowadays. This control strategy uses, in a very convenient way, the discrete nature of power converters and microprocessors used in their control.