User manual

Battery charger NG5-7-9

D01274-00 4

Operating principle

The battery charger considerably affects battery life and performances, which is the main part of every

electric vehicle.

A non controlled traditional battery charger (rectifier) provides a simple direct AC/DC conversion.

Disadvantages of this solution are:

• Low efficiency

• Large physical size

• Long charge times

• Charge depends on changes in the mains supply (with

overcharge danger in the final charge phase)

In modern battery chargers these disadvantages are solved with an indirect AC/DC conversion, by

passing through an intermediate DC/DC conversion.

This is the usual method of operation for

the SMPS (Switching Mode Power

Supply) at high power. This solution

gives a good performance for minimum

costs and physical dimensions using

switches more faster and powerful

(modern technology).

The main advantages of this solution are:

• High efficiency

• Reduced dimensions

• Short charge times

• Charge independent from the changes of the mains supply

• Electronic control that provides the desired charge curve

The advent of electrical problems (due to commutation) has imposed the introduction of adequate filtering

to satisfy requirements of EMC 89/336/EEC directive for electromagnetic compatibility.

Block Diagram

STAGE

POWER F1

LOGIC

CONTROL

FILTER

RECTIFIER

AND

FILTER FILTER

EMI EMI

Batteria