Alberto Soto Lock

Torque control of induction motor drives based on One-Cycle Control method

The first work on direct torque control (DTC) of induction motor (IM) was based on hysteresis controllers and Switching Tables. Although it has the advantage of simplicity, it has a few drawbacks such as current, torque and flux distortions, and variable frequency operation. Posterior DTC works have solved most of these problems, but with added complexity to the control algorithm. This paper presents a new flux and torque controllers, for DTC of IM drives, based on One Cycle Control (OCC). The proposed control method (DTC-OCC) is capable of solving most of the original problems of DTC such as operation at fixed frequency with reduced ripple on flux, torque and current, while recovering at the same time, the simplicity of the DTC algorithm. As OCC has been considered as a generalized PWM modulator, the theoretical foundations of the new method are provided from both PWM and OCC approaches. Simulation and DSP-based experimental results show good performance of the proposed control and confirm the theoretical analysis and assumptions.

One Cycle-Control method for obtaining Discontinuous PWM strategies to control a three-phase rectifier

This paper presents an alternative One-cycle Control applied to a controlled rectifier so that Discontinuous PWM (DPWM) techniques are obtained, equivalent to those obtained with Carrier Modulation or Space Vector Modulation. With the help of the Hybrid PWM, the DPWM mathematical description is greatly simplified giving to that technique a graphical interpretation and a simple mathematical formulation. Also, unity input power factor is obtained. Simulation and experimental results, using DSP, confirm the good performance of proposed technique.

Improved Hysteresis Current Control of a Single Phase, Three Level, Double PFC Converter

Single ended, single phase, power factor corrector (PFC) Boost Converter, is one of the most popular AC/DC converters, because of a number of advantages i.e. its step up voltage ratio, simplest topology and high efficiency. However, for high voltage or high power applications, three level PFC converter is one of the most promising solutions. For high power applications, current operation frequency and Bandwidth must be limited to avoid Electromagnetic EMI interference. This paper presents a fixed frequency hysteresis current control for Three level Single-Phase, Boost double PFC Converter. The proposed methodoly presents hysteresis current control with adaptive band error to constrain switching frequency for a given range. A fast response, a relative small bandwidth and reduced harmonic content are qualities of the technique proposed; furthermore, coupling Output Voltage problem is avoided, by means of compensating current reference. Simulation results confirm the proposed technique.

Sensitive load voltage compensation with a suitable control method

This work proposes the usage of a repetitive-based control to dynamically restore the voltage applied to grid sensitive loads. The control is able to wipe off harmonic distortion and relies on simple transfer function. As a consequence, there is no need to apply harmonic selective filters. Moreover, the filter is able to work on sinusoid references and avoids employment of the dq transform. The design of the control parameters along with the system stability are discussed. A Simulink-based simulation has been built to verify the designed control performance. The experimental results are extracted from a setup of three-phase compensator which copes correctly with different scenarios of sagged and harmonic distorted voltages.

An OCC-APF control strategy for unbalanced grid conditions

In this work it is proposed a DSP based, OCC control strategy for APF, which is able to work in case of unbalanced grid voltage, i.e. when it is affected by a common mode voltage. Proposed strategy is based on an OCC rectifier control which utilizes an input resistance control to set up dc-link voltage and achieve a unity power factor as well, and a lead-lag compensator to average phase current. In this sense, APF proposed strategy uses input resistance control while lead-lag compensator is used to filter harmonics in grid current. Simulation and experimental results confirm present proposal.

A clamping current control technique, based on one cycle control OCC

This paper proposes a clamping phase technique that results in power factor control at the input of a controlled rectifier by means of a current control based on One Cycle Control (OCC) technique. It minimizes phase interference, fixes operation frequency as well as improves phase coordination. Control simplicity and voltage input sensor elimination is the feature of the proposed control. Theoretical background of the clamping phase technique as well as of OCC principle has been reviewed and analyzed. Simulated results confirm the proposed technique.

Voltage quality enhancement with minimum power injection

This work proposes the usage of a repetitive-based control to dynamically restore the voltage applied to sensitive and critical loads of power systems. Besides, sag and voltage swells, the proposed control can intrinsically mitigate harmonic distortions. Furthermore, the filter is able to work out on sinusoid references and, thus, avoids the need of employing the dq transform. A recursive least-squares is also included to the control system in order to assure the synchronization of the injected voltages to be restored. The design of the control parameters along with the system stability are discussed throughout the paper. Also, this work aims to analyze two different types of voltage insertion into the grid through the series compensator. In the first one, the voltage injection is in synchronization with the pre-faulted grid voltage, while the second injects the voltage in a manner that the compensator spends a minimum of active power. Both types produce reference voltages that are used by the repetitive control. Additionally, simulated and experimental results are presented and corroborate the method efficacy.

An APF-OCC Strategy for Common-Mode Current Rejection

This paper proposes a DSP-based one-cycle control (OCC) strategy for a shunt active power filter (APF), which is able to reject common-mode currents caused by common-mode voltages. The proposed strategy is based on an OCC rectifier control, which utilizes an input resistance control to set up dc-link voltage and achieve a unity power factor as well as a lead-lag compensator to average phase current. In this sense, the proposed APF strategy employs input resistance to control the power factor, while a lead-lag compensator is used to filter harmonics in phase current. Simulation and experimental results confirm the presented proposal.

One Cycle Control Based Maximum Power Point Tracker Applied in Photovoltaic Systems

The utilization of solar energy has grown in the last decades, and due to the scarcity of fossil fuels and the awareness of the increasing greenhouse gases in the atmosphere, this energy tends to become predominant. For generating photovoltaic energy, photovoltaic modules are connected to converters to define the amount of energy provided to a load. A maximum power point tracking method is used to maximize the photovoltaic module output power considering the solar radiation and panel temperature. This work proposes the implementation of one-cycle control (OCC) to track the maximum power point of a photovoltaic module in direct current converters. This paper contains an analysis of response speed, reference tracking and transient, showing the applicability of the OCC technique

A current based OCC technique implemented by DSP for a three-phase OCC rectifier

In this work it is proposed a control strategy for a shunt Active Power Filter (APF) based on an One Cycle Control (OCC) Rectifier, implemented by DSR An input resistance controller to set up dc-link voltage and a lead-lag compensator to average grid current is part of this work. In addition, as DSP implementation can increase the possibilities of control of complex systems. An example of this feature is further investigated, as the ability of proposed OCC based APF to control unbalanced non-linear load. Simulation and experimental results validate the proposed work.