K. Rafał

Improved Voltage Oriented Control of AC-DC converter under balanced and unbalanced grid voltage dips

In this paper an implementation of Improved Voltage Oriented Control for AC-DC converter has been presented and investigated. Algorithm is based on independent control of positive and negative current sequences. It contains different blocks responsible for grid synchronization, mitigation of 100Hz component, current control and sequence extraction. Different line voltage feedforwards have been implemented and discussed according to harmonic components and operation of current controllers.

Hybridization of an aircraft emergency electrical network: Experimentation and benefits validation

This paper proposes a structure and two strategies for hybridization of a RAT (Ram Air Turbine) with supercapacitor storage. The structure consists in coupling a High Voltage DC (HVDC) source (RAT) with a low voltage storage device through a specific topology of bidirectional DC-DC static converter. The energy management strategies consists in entrusting the storage with the “high frequency” harmonics of the load power while the RAT only produces the average power: the RAT sizing and its mass can then be reduced. Lab test bench architecture, control strategy, topology of the converter and experimental results are presented in this paper.

Component minimized AC/DC/AC converter with DC-link capacitors voltages balancing

This paper investigates component minimized topology of single-phase to three-phase AC/DC/AC Pulse Width Modulated (PWM) converter. It consists of half-bridge rectifier and two-leg (B4) inverter and is designed for low-power induction machine (IM) drive application. Effect of voltage imbalance between split capacitor bank is discussed and improved control algorithm is proposed to minimize imbalance and compensate its impact on output power quality. Proposed method is verified experimentally with 3 kW model.

Grid interfacing of distributed energy sources by three-level BtB NPC converter under distorted grid voltage

This paper presents complete control algorithm for grid-connected Pulse Width Modulated (PWM) 3-level BtB (back to back) converter intended for industrial drives and renewable energy applications. The objective of control is to limit current harmonics distortion and provide ride through capability during voltage dips. Moreover, Maximum Power Point Tracking (MPPT) and Active Power Feedforward (PF) has been implemented end tested for optimizing energy flow control. Grid Side Converter (GSC) is controlled by Voltage Oriented Control (VOC) supported by synchronization loop with positive sequence extraction, resonant current controllers for higher harmonics compensation, grid voltage feedforward loop for dips compensation and DC voltage filter. At Machine Side Converter (MSC) Direct Torque Control Space Vector Modulated (DTC-SVM) has been used. Algorithm is tested in simulations and experiment from 3kVA up to 15kVA platform using three-level BtB NPC converter with LCL filter. Both controls of GSC and MSC are interacting by Power Feedforward for energy flow optimization between grid and active load.

Coordinated control of grid-connected three-level NPC converter under distorted grid voltage

This paper presents complete control algorithm for grid-connected Pulse Width Modulated (PWM) AC/DC converter intended for industrial drives and renewable energy applications. The objective of control is to limit current harmonics distortion and provide ride through capability during voltage dips. Following improvements to Voltage Oriented Control are presented: synchronization loop with positive sequence extraction, resonant current controllers for higher harmonics compensation, grid voltage feedforward loop for dips compensation and DC voltage filter. Algorithm is tested in simulations and on experimental 15kVA platform using three-level NPC converter with LCL filter.

Model Predictive Control of Four-Leg Three-Level Flying Capacitor Converter: Influence of Model Parameter Mismatch

Abstract This paper presents a control method for a four-leg three-level flying capacitor converter (FCC) operating as a shunt active power filter (SAPF), based on model predictive control with finite number of control states (FS-MPC). Current control and capacitor voltage balancing are described. Influence of the mismatch of the inductive filter model parameters on the current control precision is analysed. Results are supported by the experimental waveforms obtained with a 10kVA set-up.