Totempole based PFC in On Board Charger in an EV

Theory and Matlab simulation of Totempole PFC converter in EV.

In this module, you will learn all about the power factor correction in On Board chargers of an EV. The module starts with a theory of PFC , it application , necessity and advantages. On a practical level, the module then covers an interesting Matlab Simulink simulation to showcase the results.

Lecture 1 :This section of the course gives an overview about the Power factor in AC circuits.

How the Power factor is calculated ?

How a non-unity power factor comes into being in AC transmission?

How the different non-linear circuit elements create a phase shift in the current?

How lagging and leading power factors are created?

Why EVs always do a power factor correction at source?

Why EVs like a Unity power factor?

Lecture 2: This section describer about the totempole topology of power factor correction in EVs.

How a Totempole converter looks like?

Advantages of a single stage totempole converter vs a multistage doubke boost converter.

Method of operation of a totempole converter.

Sneek peak into the totempole control algorithm.

Lecture 3: This section starts with the building up of a totempole power factor correction topology in Matlab Simulink and then discusses the design of control loop.

A 4 switch totem pole power electronic converter is built in Simulink.

Suitable and required sensors are positioned in the topology.

The control alogrithm is just starting to be built - will be continued in part 2

Lecture 4 : This section continues with the control algorithm of the totempole power factor correction.

It describes a dual PI Loop to fulfil unity power factor as well as a magnitude based closed loop control strategy to ensure a stable DC output.

Results of the simulation are discussed.

A unity Power factor is illustrated in the simulation results.

Lecture 5: This section illustrates the simulation results wherein the unity power factor is achieved by the designed control strategy.

The zero crossings and peaks of the current and voltage sinusoids can be seen to be exactly in phase.

Lecture 6: This section illustrates quite beautifully how the impact of a PI loop can be observed on the ripple of the AC current. This shows how the control algotithm actively changes the switiching pulses so as to ensure a Unity power factor at all times.

Lecture 7: This section describes how a PFC topology is integrated into an OBC of a EV.

What are the stages of an OBC?

How PFC output is linked to the next stage in an OBC?

Why PFC output cannot be directly used to charge the HV battery in the EV?