Emerson Giovani Carati

Hybrid Adaptive Efficiency Control technique for energy optimization in induction motor drives

Induction motors are efficient in rated load, but its efficiency is reduced in light loads. Some controllers and techniques are presented in literature as a method to improve this performance, such the Search Controller (SC) and Loss Model Based Controller (LMC). To compare the response of efficiency controllers, the motor model is presented with current, speed and flux PI controllers. It is also presented the SC Control and LMC Control approaches. Moreover, this paper presents a new optimization technique for energy saving in induction motor drives defined Hybrid Adaptive Efficiency Controller (HAEC), which uses main characteristics of SC and LMC. The included results compare performance and energy savings of each controller and demonstrate the efficiency improvement with HAEC.

An energy based LQR tuning approach applied for Uninterruptible Power Supplies

This paper proposes a tuning method for a linear quadratic regulator (LQR) and its application to Uninterruptible Power Supplies (UPS). A performance index is established based on the desired behavior of system variables, such as maximum values permitted on the states and control law saturation. The tuning method is based on the Q and R weighting matrices, which relate the energy of the state variables involved on the process. From this index it is possible to find an optimal point to reach the required performance. The design procedure is exemplified with an output voltage control of an Uninterruptible Power Supply and dynamic results are presented.

Digital control system using a thermoelectric cell for temperature electronic devices testing

This paper presents a temperature digital control system for performance evaluation of electronic devices under different operating temperatures. The system is based on a thermoelectric module of Peltier effect, which is used for heating or cooling the device under test (DUT). A digital PI controller is designed through simulations with an electric model of the structure, developed in Simulink®. Based on the parameters and results from simulations, the controller is implemented in Labview® and experimental results are obtained using a servo amplifier like actuator.

Repetitive control techniques applied to uninterruptible power supplies

This paper presents recent repetitive control (RP) techniques applied to uninterruptible power supplies (UPS). A proportional-derivative (PD) technique including a feedforward term is implemented as the main controller. In addition, recent repetitive control laws are presented and applied to a single phase PWM inverter. It is also presented a new RP approach for repetitive gain adaptation in the presence of cyclic and random disturbances. Results demonstrate the efficiency of each control approach.

Dynamic behavior of the PV Grid-connected inverter based on L and LCL filter with active damping control

PV Grid-connected inverters must fulfill the standards specifications of current harmonics injected to the grid. In order to satisfy these grid requirements, passive filters are connected between the inverter and the grid. This paper compares the response characteristic of the traditional inductive (L) filter with the inductive-capacitive-inductive (LCL) filter. It is shown that the increasing the inductance L leads to a good ripple current suppression around the inverter switch frequency. The LCL filter provides better harmonic attenuation and reduces the filter size. The main drawback is the LCL filter impedance, which is characterized by a typical resonance peak, which has to be damped to avoid instability. Passive or active techniques can be used to damp the LCL resonance. To address this issue, this paper presents a comparison of passive and active damping strategies. Experimental results are given to support the theoretical analysis and to illustrate the performance of grid connected PV inverter system.

A new model based control strategy for energy efficiency improvement of induction motors with variable load

This paper proposes a new control strategy for energy efficiency improvement of three-phase induction motors (TIM) with variable load. Main control is based on Indirect Field-Oriented (IFOC) which shows a good performance of torque and speed. Additionally it is proposed a new loss model based controller in order to optimize the active power consumed by TIM for different load conditions. Matlab simulations are performed to test the proposed strategy for different loads where the optimal flux is found. The strategy is also tested using PSIM simulation where the drive system is included. To verify the approach in real conditions a motor drive prototype was assembled and experimental results are presented.

A power electronics and digital control experiment applied to teaching interdisciplinary in electrical engineering

This paper presents a interdisciplinary teaching experience applied to power electronics and digital control. The boost converter with a discrete-time PI controller implemented in a microcontroller is used in this experiment. It is presented a boost converter model and the controller design, beyond the description of instrumentation circuit used. Finally are presented experimental and simulated results. This experiment is applied to UTFPR electrical engineering students.

Input command strategies and analysis for energy optimization of induction motor drives

This paper proposes an analysis of energy consumption in three-phase induction motors (TIM) drives. The main control is based on the indirect field-oriented (IFOC) approach. A performance analysis is carried out for different types of input commands to the speed motor drive, such as the usual step and ramp inputs. Moreover, sigmoid and model reference step based inputs are proposed to smooth the transient behavior as well as to improve the overall drive energy efficiency. In this way, Matlab simulations are carried out to analyze reference inputs for several operation conditions. In order to verify the approach in real situations, a three-phase 4hp motor drive platform is implemented using a PWM inverter and a F28069 DSP. The energy consumption performance is demonstrated through simulations and experimental results.

Emulation of Wind Turbines

This chapter presents the modeling, simulation, and emulation for small wind turbine (WT) systems. The main objective of the emulation system is to reproduce the WT torque dynamic behavior in the generator shaft, which must be similar to one of real horizontal WTs used for distributed generation. The aerodynamic, mechanical, and electrical models for horizontal axis wind turbines (HAWTs) are presented in detail. The models are used for simulation analysis and emulation synthesis. The emulator consists a (i) computational platform, which is based on LabVIEW® environment and runs the model of the WT and (ii) an induction motor (IM) with AC power drive with torque control. The IM shaft is directly coupled with the real small wind generator and corresponding load. Experimental waveforms are also presented to demonstrate the functionality of the system.

Comparison of diode full-bridge rectifier and voltage-doubling diode rectifier in the output stage of active-clamping current-fed half-bridge isolated DC-DC converter

This paper proposes the use of voltage-doubling diode rectifier in the output stage of the zero-voltage-switching active-clamping current-fed half-bridge isolated DC-DC converter and presents a comparison with the classic diode full-bridge rectifier. The design methodology was revised to include the voltage-doubling rectifier and lower side clamp capacitor connection. Two converters (diode bridge rectifier and voltage-doubling rectifier) were designed and experimented to show the expected results and waveforms.