Branko Blanusa

Power loss model for efficiency improvement of boost converter

The analytical expressions for boost converter loss are presented in this paper. All significant sources of conduction and dynamic losses within the converter elements, including losses in choke magnetic material and switching losses which occur due to diode recovery time, are discussed. Sources of losses in continuous and discontinuous current mode of converter are examined. The equivalent input resistance of the generator is included in converter loss model. In the paper, the case when single-phase rectifier is input circuit of the converter is presented. Loss model of converter and its efficiency was compared with experimental measurements on a prototype of the boost converter.

Boost converter efficiency optimization in wind turbine

A method for efficiency optimization of boost converter applied in wind turbine with permanent magnet generator (PMG) is proposed in this paper. This method gives the best results when output power of generator is less than rated value. Its validation is verified through simulation and experimental results.

A novel direct torque and flux control algorithm for the induction motor drive

In this paper a new sensorless Direct Torque Control (DTC) algorithm for induction motor drive is proposed and tested. This algorithm provides decoupled control of the torque and flux with constant inverter switching frequency and a minimum torque and flux ripple. Compared to the other DTC methods, this algorithm is much simpler and has less mathematical operations, and can be implemented on most existing digital drive controllers. Algorithm is based on imposing the flux vector spatial orientation and rotation speed, which defines the unique solution for reference stator voltage. The implementation of the control scheme using DSP-based hardware is described, with complete experimental evidence and the straightforward implementation instructions.

Model of elevator drive with jerk control

A strong jerk which can cause passengers discomfort occurs when electric elevator starts and stops. If uncontrolled, the jerk have influence on the electrical and mechanical subsystem performance and reduce the system life expectance. Modern drives have ability to control speed, so we can indirectly control the jerk. This paper describes the control of real gear-less electric elevator drive with vector-controlled induction motor. Position trajectory is determined by the need that jerk is changed by the predefined function. A mathematical model of the drive is presented, and it is tested through computer simulations.

Algorithm for efficiency optimization of the boost converter in wind turbine

Implementation of a method for efficiency optimization of boost converter in wind turbine with permanent magnet generator is described in this paper. This method is based on variable switching frequency technique suitable in conditions when input power of the converter is less than rated. The proposed concept is verified through computer simulation of the boost converter and experimental measurements on the prototype.

Optimal flux control of elevator drive

Modern gearless elevator drives have ability to control speed and other parameters of motion like a jerk. Also techniques for indirect vector-control of induction motor provides possibility for efficiency optimization. This paper describes control algorithm based on optimal control. It combines two crucial elements for elevator drive, smooth motion which increase comfort of elevator passengers and minimum energy consumption for one elevator drive. Validity of suggested algorithm is tested through computer simulations.

Simple Hybrid Model for Efficiency Optimization of Induction Motor Drives with Its Experimental Validation

New hybrid model for efficiency optimization of induction motor drives (IMD) is presented in this paper. It combines two strategies for efficiency optimization: loss model control and search control. Search control technique is used in a steady state of drive and loss model during transient processes. As a result, power and energy losses are reduced, especially when load torque is significant less related to its rated value. Also, this hybrid method gives fast convergence to operating point of minimal power losses and shows negligible sensitivity to motor parameter changes regarding other published optimization strategies. This model is implemented in vector control induction motor drive. Simulations and experimental tests are performed. Results are presented in this paper.

An algorithm for boost converter efficiency optimization

In this paper, an algorithm based on the technique of variable switching frequency is applied, so that working point of boost converter is at the boundary between continuous and discontinuous working mode aiming at achieving maximum efficiency of the converter. Controller is based on variable switching frequency and measuring the voltage on the main converter switch. The proposed algorithm is verified by the simulations and experimental measurements on a converter prototype.

Elevator drives: Present trends and perspectives

In this paper some of the problems related to electrical drives in modern elevators are presented. These are the modeling of jerk and the definition of the motion trajectory, power savings, efficiency optimization and possibilities for energy storage in generator mode, and application of suitable converters and control techniques for the implementation in elevator drives. Suggested solutions are tested through computer simulations and experimentally on the prototype of elevator drive.

Introduction to Multilevel Converters

Multilevel converters have found an important position among applications as high-power converters. Also, they are widely used in renewable energy sources where multilevel converters appear as a link between renewable sources, such as wind, fuel cells, photovoltaic modules from one side and high-power loads from the other side. Power converters for high-power AC motors, systems for reactive power compensation, Flexible Alternative Current Transmission Systems (FACTS) devices and inverters in tracking vehicles have become typical applications in which multilevel converters are used.