Modified digital space vector pulse width modulation realization on low-cost FPGA platform with optimization for 3-phase voltage source inverter

The realization of power electronic applications on hardware is a challenging task. The digital control circuit strategies are used to overcome the analog control strategies by providing great flexibility with simple equipment and higher switching frequencies. In this manuscript, an area optimized, modified digital space vector (DSV) pulse width modulation is designed and realized on low-cost FPGA. The modified digital space vector pulse width modulation (DSVPWM) uses a phase-locked loop (PLL) to generate clocks using the digital clock manager (DCM). These DCM clocks are used in the DSVPWM module to synchronize the other sub-modules. The voltage generation unit generates the three-phase (3-Ф) voltages and is used in the alpha-beta generation and sector determination unit. The reference active vectors are made by the reference generation unit and used in switching time calculation. The PWM pulses are generated using switching time generation, and lastly, the dead time occurrence unit generates the final SVPWM gate pulses. The modified DSVPWM is synthesized and implemented on Spartan-3E FPGA. The modified DSVPWM utilizes 17% slices, works at 102.45 MHz, and consumes 0.070 W total power. The simulation results and the resource utilization of modified DSVPWM are represented in detail. The modified DSVPWM is compared with existing PWM approaches on different Spartan-series FPGAs with better chip area improvemen

Implementation and verification of a hardware-basedcontroller for a three-phase induction motor on an FPGA

L’objectiu d’aquesta tesi és estudiar diverses tècniques de control motor per tal d’implementar i verificar un controlador basat en hardware per a un motor d’inducció trifàsic desenvolupat en llenguatge VHDL i funcionant en una FPGA Artix-7 (Xil-inx). Aquest controlador està basat en tècniques de variació de freqüència. Els mòduls que defineixen la descripció de hardware funcionen simultàniament entre ells, i permeten agilitzar el sistema, millorant el rendiment i la resposta del motor, en comparació amb un microcontrolador. Aquesta tesi està relacionada amb els sistemes digitals, l’electrònica de potència i els sistemes de control.Outgoin

Control in multi-motor electric vehicle with a FPGA platform

A new FPGA based platform is presented for controlling a Multi-Motor Electric Vehicle (EV). By exploring the FPGA parallel processing capabilities, two induction motor controllers, based on Field Orientation Control and Space Vector Modulation techniques, were merged in a single and compact chip. Implementation issues related with the limited number of dedicated multipliers were overcome using an efficient computational block, based on resource sharing strategy. The developed IP Cores were carefully optimized to fit in a low cost XC3S1000. Experimental results, obtained with a multi-motor EV prototype, demonstrate the proper operation of the proposed propulsion system

Neutral Point Clamped Transformerless Multilevel Converter for Grid-Connected Photovoltaic System

Transformer-less (TL) inverter topologies have elicited further special treatment in photo-voltaic (PV) power system as they provide high efficiency and low cost. Neutral point clamped (NPC) multilevel-inverter (MLI) topologies-based transformer-less are being immensely used in grid-connected medium-voltage high-power claims. Unfortunately, these topologies such as NPC-MLI, full-bridge inverter with DC bypass (FB-DCBP) suffer from the shoot-through problem on the bridge legs, which affect the reliability of the implementation. Based on the previous above credits, a T type neutral point clamped (TNP) - MLI (TNP-MLI) with Transformer-less topology called TL-TNP-MLI is presented to be an alternate which can be suitable in the grid connected PV power generation systems. The suggested TL-TNP-MLI topologies free from inverter bridge legs shoot-through burden, switching frequency common-mode current (CMC), and leakage current. The control system of the grid interface with hysteresis current control (HCC) strategy is proposed. The effectiveness of the proposed PV connected transformer-less TNP-MLI topology with different grid and PV scenario has been verified through the MATLAB/Simulink simulation model and field-programmable gate area (FPGA) based experimental results for a 1.5 kW system.publishedVersio

POWER QUALITY CONTROL AND COMMON-MODE NOISE MITIGATION FOR INVERTERS IN ELECTRIC VEHICLES

Inverters are widely utilized in electric vehicle (EV) applications as a major voltage/current source for onboard battery chargers (OBC) and motor drive systems. The inverter performance is critical to the efficiency of EV system energy conversion and electronics system electro-magnetic interference (EMI) design. However, for AC systems, the bandwidth requirement is usually low compared with DC systems, and the control impact on the inverter differential-mode (DM) and common-mode (CM) performance are not well investigated. With the wide-band gap (WBG) device era, the switching capability of power electronics devices drastically improved. The DM/CM impact that was brought by the WBG device-based inverter becomes more serious and has not been completely understood. This thesis provides an in-depth analysis of on-board inverter control strategies and the corresponding DM/CM impact on the EV system. The OBC inverter control under vehicle-to-load (V2L) mode will be documented first. A virtual resistance damping method minimizes the nonlinear load harmonics, and a neutral balancing method regulates the unbalanced load impact through the fourth leg. In the motor drive system, a generalized CM voltage analytical model and a current ripple prediction model are built for understanding the system CM and DM stress with respect to different modulation methods, covering both 2-level and 3-level topologies. A novel CM EMI damping modulation scheme is proposed for 6-phase inverter applications. The performance comparison between the proposed methods and the conventional solution is carried out. Each topic is supported by the corresponding hardware platform and experimental validation

An improved FPGA implementation of direct torque control for induction machines

This paper presents a novel direct torque control (DTC) approach for induction machines, based on an improved torque and stator flux estimator and its implementation using Field Programmable Gate Arrays (FPGA). The DTC performance is significantly improved by the use of FPGA, which can execute the DTC algorithm at higher sampling frequency. This leads to the reduction of the torque ripple and improved flux and torque estimations. The main achievements are: i) calculating a discrete integration operation of stator flux using backward Euler approach, ii) modifying a so called non-restoring method in calculating the complicated square root operation in stator flux estimator, iii) introducing a new flux sector determination method, iv) increasing the sampling frequency to 200kHz such that the digital computation will perform similar to that of the analog operation, and v) using two’s complement fixed-point format approach to minimize calculation errors and the hardware resource usage in all operations. The design was achieved in VHDL, based on a Matlab/Simulink simulation model. The Hardware-In-the-Loop (HIL) method is used to verify the functionality of the FPGA estimator. The simulation results are validated experimentally. Thus, it is demonstrated that FPGA implementation of DTC drives can achieve excellent performance at high sampling frequency

Improved control for multilevel inverters in grid applications

Control systems for three-phase grid connected voltage source inverters (VSI) play an important role in energy transformation systems . They are expected to be stable, robust and accurate during steady state as well as different grid faults and disturbances like voltage sags or unbalanced conditions. Caused by increasingly rising grid standards and efficiency requirements the use of multilevel inverter systems in grid connected low voltage applications are getting more and more attention. Nevertheless, the use of these inverter types leads to increased complexity of the control system and the hardware components. This thesis presents an improved control scheme for multilevel inverters in grid applications. The system combines a robust and high-dynamic direct current control scheme called scalar hysteresisEn molts casos i, cada cop més, els sistemes de transformació energètica estan basats en convertidors en font de tensió connectats a la xarxa elèctrica trifàsica. Aquests convertidors necessiten de sistemes de control per controlar els fluxos energètics. Els sistemes de control han de ser estables, però també robustos i precisos durant el seu funcionament normal, però també en condicions on la xarxa pot presentar defectes, com curtcircuits, sots de tensió o desequilibris en la tensió. Degut a l'increment dels requeriments tècnics de connexió i d'eficiència energètica, els convertidors multinivell estan guanyant molt d'interès en aquest tipus d'aplicacions connectades a la xarxa tot i que el seu control i els seus components siguin més complexes. Aquesta tesi presenta un mètode de control per convertidors multinivell connectats a la xarxa elèctrica. El mètode combina la robustesa davant de canvis en el sistema així com una alta capacitat dinàmica per controlar el corrent injectat a la xarxa. El mètode presentat esta basat en l'anomenat Scalar Hysteresis Control (SHC) i incorpora un sistema feedforward que li permet seleccionar acuradament el punt de treball i seleccionar al millor estat de commutació en cada moment. La combinació del SHC amb el feedforward garanteix un comportament robust amb una alta dinàmica en totes les condicions de funcionament. El concepte bàsic del mètode feedforward proposat no usa sensors i està basat en detectar la tensió de l'inversor que inclou les components harmòniques. El mètode està basat en l'ús d'integradors generalitzats de segon ordre (second order generatlized integrators, SOGI) per tal de detectar les components harmòniques de la tensió de sortida de l'inversor. El sistema pot operar sense sensor de tensió, fins i tot en situacions de defecte de la tensió. Fins i tot, la informació extreta del SOGI es pot usar per altres llaços de control d'ordre superior com el control de la potencia usant les components simètriques. Per a determinar els millors estats de commutació de l'inversor amb el menor esforç s'usa en el mètode proposat en aquesta tesi un canvi de coordenades que usa valor enters. Aixo permet l'ús de relacions matemàtiques senzilles que es poden implementar fàcilment i que requereixen una menor potencia de càlcul. A més, el mètode és fàcilment generalitzable . En la tesi es presenten simulacions i resultats experimentals en convertidors multinivell de tres i cinc nivells per tal d'investigar i demostrar les funcionalitats del sistema de control proposat. Tant les simulacions com els resultats experimentals es realitzen en totes les condicions possibles de la xarxa elèctrica, estat estacionari, sots i distorsions harmòniquesPostprint (published version

FPGA Applications in Hybrid Energy Storage System and Field-oriented Motor Control

This thesis demonstrates the utilization of FPGA chip in hybrid energy storage system (HESS) and motor control, which contains four sections. 1. In order to compensate for such mismatches, a HESS composed of battery and ultracapacitor (UC) is presented in this thesis. To optimize the power allocation in the HESS, a global-level fuzzy logic-based power management strategy is proposed. It has the following objectives: 1) manage the power distribution between the battery and the UC to achieve power balance without over charging/discharging the two sources; 2) make full use of the nature of the two sources to smooth out power fluctuation and extend the lifespan of batteries. Case studies are provided under various scenarios. 2. This thesis not only considered the PV-involved system, it also considered hybrid electric vehicles (HEV) system issues, which means we also developed two fuzzy logic power management strategies for HEV-involved system. The goal is to investigate the effect of two fuzzy logic strategy when considering battery degradation. In that case, the battery degradation model is presented and compared. The simulation results verified that one of the proposed strategy can greatly reduce the battery degradation. 3. Due to the fluctuation and instability of photovoltaic (PV) output power, mismatches between the power supply and the power demand may occur in a stand-alone PV system. In order to test the potential of FPGA chip, both fuzzy algorithm and field-oriented control (FOC) algorithm are implemented in FPGA. The digital design of each fuzzy logic stage is presented. The results validate the effectiveness of the proposed fuzzy logic-based power management strategy. 4. For FOC algorithm implementation, the goal is to utilize the rapidity of the FPGA chip to generate high-frequency PWM signals for power converter board. Both simulation and hardware results are presented, which shows the advancement of FPGA chip.Master of Science in EngineeringElectrical Engineering, College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttps://deepblue.lib.umich.edu/bitstream/2027.42/140770/1/masterThesis_1222.pdfDescription of masterThesis_1222.pdf : Master's Thesi