English
Battery charger NG5-7-9
12
D01274-00
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.
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 Scheme
F0
F2
F4
E
T
S
R
STAGE
POWER
F1
LOGIC
CONTROL
FILTER
FILTER
FILTER
RECTIFIER
RECTIFIER
RECTIFIER
AND
AND
AND
FILTER
FILTER
EMI
EMI
Batteria
i
i
i
v
DC
AC
Batteria
i
i
i
v
DC
DC
DC
AC
