October 2014
38
A
UTOMOTIVE
Configurable hardware for automotive
alternator regulator designs
By Dr. Eckart Voskamp,
EBVchips
The Epona alternator regulator can
increase the efficiency of generators
in 24V and 12V on-board electrical
systems in commercial vehicles and
passenger cars. A basic hardware
system that can be used in all
designs is ideal here because it
can be adjusted in line
with the specific customer system
by means of software.
Up until now, no suitably sophisticated
hardware has been available that enables gen-
erators in commercial vehicles, agricultural
and construction machinery as well as other
vehicles with internal 24V on-board electrical
systems to be operated at maximum efficiency.
To address this, EBV Elektronik collabo-
rated with STMicroelectronics to develop
the Epona generator regulator as part of the
EBVchips line. Designed for vehicles with 24V
on-board electrical systems, the component is
also suitable for use in 12V on-board electri-
cal systems in passenger cars.
Although a number of application-specific
standard products (ASSPs) are already avail-
able for regulating generators, each individ-
ual ASSP is specifically adapted in line with
the individual requirements of a single OEM.
With Epona, however, suppliers now have a
basic design for regulating generators and
so are able to cover the requirements of all
vehicle manufacturers – a first in the industry.
The basic idea behind Epona was to offer as
many degrees of freedom as possible in order
to enable a highly efficient system design on
the one hand and to implement the necessary
control algorithms on the other. Although
it would theoretically have been possible to
create a system like this as a highly efficient
controller, the numerous different vehicle
manufacturer specifications mean that the
control loop must be user-programmable to
avoid the need to develop an individual ASSP
for each solution.
This is exactly where the EBVchip comes
in, because the heart of Epona is a user-pro-
grammable microcontroller in which a state
machine can, in principle, be mapped. To help
program the microcontroller, EBV Elektronik
supplies a tool that allows simulation of the
control loop and the setting of all the other
parameters quickly and easily. Thanks to their
system expertise, the developers no longer
have to worry about creating, for example, a
standard P-controller. Now all they have to do
is set the relevant control parameters in their
software. A generator regulator ensures – usu-
ally by means of normal proportional control –
that the generator is operating at the optimum
control point. In conventional solutions, these
regulators are implemented in standard, ana-
log hardware. Standard silicon offering only
standard levels of efficiency is normally used
here. Thanks to more complex algorithms,
however, the generator regulator ensures that
the generator is always operating as close
as possible to the optimum control point,
thereby achieving the best-possible efficiency.
With Epona, all that is needed is a single sys-
tem board, which can then be easily adapted
in line with the requirements of the generator
or end-customer and so cover the individual
requirements of an application with different
equipment variants. In addition to the degree
of freedom offered by the hardware, it also
offers a degree of freedom with regard to the
software, whereby the threshold values can be
set during analysis of the measured values.
When EBV Elektronik presented the Epona
concept two years ago, various customers –
including some with whom the company had
not even discussed the chip – provided valu-
able input. The design team successfully real-
ised most of their requests to create a highly
universal component. The original plan was
to develop a single component, but thanks
to the flexible state-machine-based concept,
EBV Elektronik is in a position to create an
entire product range at reasonable cost. In
partnership with STMicroelectronics, EBV
is currently developing a 12 and 24V range
with different bus interfaces, which will soon
result in four different components: one 12V
and one 24V version of Epona, each with and
without a LIN interface.
There is currently no uniform design direc-
tion in the development of the generator
systems and LIN is still far from being avail-
able in all new designs, which means that the
concepts of tomorrow will still use different
interface solutions and protocols; this is par-
ticularly the case for 24V applications. Since
