English
Operation 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.
i
AC
i
v
DC
i
In modern battery chargers these disadvantages are solved with an indirect AC/DC conversion, by
passing through an intermediate DC/DC conversion.
i
AC
i
v
DC
i
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 Scheme
F0
R
EMI
F1
S
FILT ER
F2
T
E
14
Battery charger NG5-7-9
Disadvantages of this solution are:
Low efficiency
•
Large physical size
•
Batteria
Long charge times
•
Charge depends on changes in the mains supply (with
•
overcharge danger in the final charge phase)
DC
Batteria
DC
RECTIFIER
AND
FILTER
RECTIFIER
AND
FILTER
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).
POWER
RECT IFIER
AND
STAGE
FILT ER
CONTROL
LOGIC
F4
EMI
FILTER
D01274-05