TMS320F28335 Digital Signal Processor Research Articles

DSP based Implementation of Vector Controlled Induction Motor Drive using Sliding Mode Speed Control Strategy

This paper deals with the implementation of Vector Controlled Induction Motor Drive (VCIMD) system using a TMS320F240 digital signal processor (DSP). The closed loop control scheme utilizes Sliding Mode Control (SMC) strategy in its outer speed loop while the inner loop is equipped with the Pulse Width Modulated (PWM) current controller. The power circuit of the system consists of a three-phase IGBT based voltage source inverter (VSI), feeding a three-phase squirrel cage induction motor. The control circuits comprise of sensors (for sensing speed and current signals), interfacing circuits and control software (processed in DSP). The sensed speed and sensed winding currents in two of the three phases are used as feedback signals for the closed loop control structure. Test results are presented for starting, speed reversal and load perturbation on the developed VCIMD system.

Sliding-mode observer for speed-sensorless induction motor drives

A sliding-mode observer for the speed-sensorless direct torque vector control of induction motors is proposed. The observer estimates the motor speed, the rotor flux, the angular position of the rotor flux and the motor torque from measured terminal voltages and currents. The use of the nonlinear sliding-mode technique provides very good performance for both low- and high-speed motor operation and robustness in motor losses and load variations. The proposed observer does not uses a PI controller and complicated observer gains and that establishes an easy setup for any type of motor. Also, the convergence of the proposed observer is examined using the Lyapunov theory. Experimental results using a TMS320F240 digital signal processor are presented for low–speed operation (5 Hz), full speed operation (50 Hz), and forward to reverse operation. Finally, the proposed observer is compared with other recently reported model-reference adaptive system techniques.

DSP-based PLL-controlled 50–100 kHz 20 kW high-frequency induction heating system for surface hardening and welding applications

A digital signal processor (DSP)-based phaselocked loop (PLL)-controlled high-frequency induction heating system is described. The rectifier and insulated gate bipolar transistor (IGBT) inverter are controlled by a TMS320F240 DSP system, which has the hardware feature of providing a dead-band delay independent of the frequency of operation. This feature, together with the high speed of the DSP, allows the use of zero current resonant switching at a high power factor for frequencies up to 100 kHz. Resonant operation of the inverter is maintained by a simple digital PLL scheme implemented on the DSP. The frequency converter enables safe operation at all load conditions with digital overcurrent, overvoltage and overtemperature protection features. The cost-effective system described is operated successfully at outputs up to 19.8 kW at 72 kHz and 500 V.

Digitally-controlled single-phase single-stage AC/DC PWM converter

The paper presents the implementation of a fully digital controller for a boost integrated AC/DC PWM converter. The considered converter has the following basic features: high power factor, full control of the DC output voltage, high-frequency line filter inductor and insulation transformer. Its main advantage is the complete integration of a rectifier and an inverter stage, requiring only four IGBTs and six diodes. The converter is described in detail and the structural limitations of its operation are highlighted. The paper focuses on the converter control strategy describing in detail the implementation, by means of the TMS320F240 digital signal processor, of a fully digital, predictive, input current control technique. An application specific modulation strategy is also developed that allows simultaneous input current and output voltage control. The control system is finally tested on a 0.5 kW laboratory converter prototype. The presented results validate the design procedure and illustrate the achievable converter performance.

POWER CONTROL OF A BRUSHLESS PERMANENT MAGNET ELECTRIC MACHINE FOR EXERCISE BIKES

This paper presents a power control structure for a brushless permanent magnet electric machine, where both generating and motoring operation modes using the same power stage coexist using a digital control scheme. In the generating mode, desired dynamic output such as constant power and constant torque can be achieved for use in an exercise bicycle, where the input power generated by pedaling is transferred into the battery in the form of electrical energy to provide braking resistance, known as the regenerative braking. The user controls the resistance via a closed-loop torque controller to the desired exercise, also the study uses three position Hall sensors instead of an expensive encoder, to perform the commutation and speed estimation. Both the theoretical derivation and experimental verification for the proposed control scheme are presented in this paper, which is implemented using a TI TMS320F240 digital signal processor.

A novel high-performance voltage regulator for single-phase AC sources

Regulation of load voltage in single-phase applications is becoming an important issue for critical loads. This paper presents a novel high-performance single-phase voltage regulator which has a common arm between the rectifier and inverter, and adopts an appropriate switching strategy. The proposed voltage regulator employs six switches and can be implemented by only one three-phase inverter module. The proposed voltage regulator has the capability of delivering sinusoidal input current with unity power factor, good output voltage regulation, and bidirectional power flow. For these purposes, a fully digital controller is designed and implemented using a TMS320F240 digital signal processor. In addition, a novel low-cost AC capacitor is also presented. This type of capacitor requires two DC capacitors and two diodes, enabling low-cost and compact manufacturing. Consequently, the complete voltage regulator system, which is mainly suitable for an uninterruptible power supply as well as reactive or nonlinear loads, can be constructed compactly and inexpensively. Experimental results are presented to verify the feasibility of the proposed voltage regulator system.

Adaptive sliding-mode observer for speed-sensorless control of induction motors

This paper presents an adaptive sliding-mode observer for the speed-sensorless field-oriented control of induction motors. The observer detects the rotor flux components in the two-phase stationary reference frame by the motor electrical equations. The motor speed is estimated by an additional relation obtained by a Lyapunov function. The analytical development of the sliding observer and the speed estimation algorithm is fully explained. Experimental results are presented, based on a TMS320F240 digital signal processor controller implementation. The system performance with different observer gains and the influence of the motor parameters deviations are shown and discussed.

Motoring to Louisville

This paper presents a power control structure for a brushless permanent magnet electric machine, where both generating and motoring operation modes using the same power stage coexist using a digital control scheme. In the generating mode, desired dynamic output such as constant power and constant torque can be achieved for use in an exercise bicycle, where the input power generated by pedaling is transferred into the battery in the form of electrical energy to provide braking resistance, known as the regenerative braking. The user controls the resistance via a closed-loop torque controller to the desired exercise, also the study uses three position Hall sensors instead of an expensive encoder, to perform the commutation and speed estimation. Both the theoretical derivation and experimental verification for the proposed control scheme are presented in this paper, which is implemented using a TI TMS320F240 digital signal processor.