Overview of fast on‐board integrated battery chargers for electric vehicles based on multiphase machines and power electronics

Abstract

The study provides an extensive overview of on-board integrated chargers for electric vehicles that are based on multiphase (more than three phases) machines and power electronics. A common attribute of all discussed topologies is that they do not require a charger as a separate device since its role is transferred to the already existing drivetrain elements, predominantly a multiphase machine and an inverter. The study demonstrates how additional degrees of freedom that exist in multiphase systems can be conveniently utilised to achieve torque-free charging operation. Therefore, although three-phase (or multiphase) currents flow through machines' stator windings, they do not generate any torque; thus the machines do not have to be mechanically locked. Cost and weight saving is achieved in this way, while the available space is increased. For each topology operating principles are explained, and its control elaborated in detail for both charging and vehicle-to-grid mode. Finally, the validity of theoretical considerations and control algorithms of some of the existing charging solutions is experimentally verified and experimental performance of all discussed topologies is compared.

Analysis of the magnetomotive force in the multiphase machines within integrated battery chargers for the electric vehicles

“…Takođe, potrebna je i specijalna mašina sa izvodima na sredini faznih namotaja, kao i pretvarač sa 12 prekidača. Brzo punjenje se može ostvariti i korišćenjem sinhrone mašine sa pobudnim namotajem, čiji su krajevi u režimu punjenja otvoreni [7]. Mane ovog sistema su potreba za hardverskom rekonfiguracijom pri prelasku između radnih režima i potreba za pobudnim sistemom.…”

“…Primenom navedenih transformacija na sistem od 6 faznih struja dobijaju se u opštem slučaju dve međusobno normalne ravni i dve nulte komponente struje, pri čemu stvaranje obrtnog polja određuje isključivo ravan koja sadrži d-q komponente struje [7]. U motornom režimu rada nulte komponente struje se ne mogu uspostaviti ako su zvezdišta izolovana, dok će u slučaju gde su zvezdišta spojena doći do uspostavljanja jedne nulte komponente struje.…”

“…Razlika se ogleda u broju nultih komponenti struje. U opštem slučaju [7], petofazni sistem daje rezultat transformacija sa samo jednom nultom komponentom struje. Prednost petofaznog sistema je što za isti broj dodatnih stepena slobode koristi jednu granu manje u pretvaraču, dok se prednost šestofaznog sistema ogleda u uvećanju ukupne snage zbog prisustva dodatne faze.…”

“…Uvažavajući način formiranja statora sa punim navojnim korakom, navojak čine provodnici u dijametralno postavljenim žlebovima. Postojanje struja u ovako definisanom navojku dovodi do pravougaone promene MPS duž obima statora, koja se predstavlja izrazom (7). Svaki navojak statora je definisan izrazom (7) u kojem je v oznaka faze, i oznaka navojka u posmatranom faznom navojnom pojasu, dx korak ožlebljenja statora, k = f (v, i) pomeraj navojka i posmatrane faze v, a x ugaoni pomeraj koji uzima diskretne vrednosti.…”

Multidirectional power flow control among double winding six-phase induction machine winding sets

“…As already mentioned, there are several practical applications of the multiple three-phase induction machines such as, more-electric aircrafts [3][4][5] and electrical vehicles (EVs) [8][9][10][11]. In the latter application, the electrical power generation and distribution systems are expected to raise from the conventional low dc voltage to a higher dc voltage level in the near future.…”