THYRISTOR-BASED power converters play an important role to the transient and steady state operation of modern power networks.
State of the art thyristor converters based on powerful microcomputers will become a main element of intelligent excitation systems in the near future.
The develop-ment
and integration of such microcomputers-based controllers may find fertile ground in practical problems such as upgrad-ing obsolete electric traction drives [1], battery charging for electric vehicles [2]
and interfacing small-scale wind turbine generators [3].
Regulated current sources are used in industry to control direct current machines,
where three-phase rectifiers operate as main static power sources.
In the 60s, regulated current sources based on analog circuitry were very popular.
As a consequence, traditional modelling for AC/DC rectifiers was made with a time-delay element in the s-domain.
This approach adequately characterized the system because the many large machinery systems show slow time responses [4].
However, systems based in power electronics devices such as regulated current sources were no longer analyzed as continuous systems in the 80s,
since it was noted that converters operate in a discrete state.
This new trend led the modelling and analysis of converters from a continuous do-
main to a discrete domain.
Therefore, the per-unit modelling of digital controlled power converters is implemented with a zero-order hold.
The modelling in the discrete domain demanded the design of discrete controllers and management of digital signals.
Digital controllers reported in [5]-[7] exploited the processing capabilities, low power consumption and low cost of dedicated microcontrollers [8].
Developments reported in literature [9]-[11] with the use of Digital Signal Processors
have exploited their features for industrial and research appli-cations.
In a recent contribution, a thyristor converter based on dsPIC controller is proposed, focusing on functions for intelligent detection and control modules [12]
In this paper, a three-phase thyristor converter based on a Digital Signal Controller (DSC) for constant-current, closed-loop control is presented. This paper introduces the devel-opment of the control system in the DSC, as well as the implementation of the prototype in the laboratory.
A wide range of simulation results and experiments in the laboratory are reported in order to evaluate the performance of the DSC-based thyristor converter in terms of speed response, harmonic content and time domain waveforms.
The DSC-based thyristor converter incorporates advanced features such as high-speed peripherals and a bandwidth for intensive computations.