Product specifications

• Participation in several international
product development projects
enables us
to follow international trends, innova-
tions and markets.
• Engineering of product ideas towards
full grown industrial products, does not
only require sound conceptual, electrical
and embedded software engineering, but
also fast knowledge and experience with
production techniques. The quality of a
product is strongly determined by the
way it is produced: a good design deals
with possible problems during produc-
tion in advance: during the engineering
stage.
Co-development with our produc-
tion partners is crucial in this respect.
Production: a joint effort
All Mastervolt products are produced in
close partnership with dedicated produc-
tion companies. All these companies are
ISO9001 certified and selected on basis of
their experience with state-of-the-art tech-
nologies and their capacity to work togeth-
er with our research and engineering de-
partment on the engineering of our pro-
ducts. As explained, co-development with
our production partners is crucial to get a
high quality design. In a joint effort, de-
sign of the products is optimised, produc-
tion lines and test facilities are set up, befo-
re production starts. The Sunmaster QS
products consist of power or main boards,
with all power electronics, and several con-
trol boards, with microprocessors and con-
trol electronics. They are assembled at dif-
ferent production lines using different
production methods. The main boards are
produced on insert machines for the small
components and hand-insert lines for lar-
ger components (transformers, capacitors,
etc.). The control boards are produced
using the fast and compact SMD (Surface
Mounted Devices) technology.
Quality Control
The quality of our products is guarded during
three stages:
• During product development: evaluation and
testing of the prototype products.
• During the last development stages and pro-
duction start-up: co-development with our
producing partners.
• Production: testing protocol for each unit
under production.
The test protocol during production is depicted
in the scheme shown here.
Visual inspection
When all boards arrive from the production
lines, they are visually inspected for incorrect
inserts, physical damage of the components and
soldering errors.
In Circuit Testing (ICT)
During the ICTesting, the boards are placed on
a needle bed. The needles from the needle bed
contact certain points in the circuitry.
The ICTesting is first used to test individual
components and parts of the circuitry. But, since
the whole power conversion, including transfor-
mers, is on one board, the ICTest can also be
used for a partial functional test. This is one of
the benefits of the HF power technology with
small transformers that are mounted on the
actual board. The ICTest is automated and pro-
duces a report of all individual measurements.
The ICTest is the most detailed testing method
available and is the most crucial test in the
whole program.
Programming and functional testing
The microprocessors on the control board are
programmed on the ICTester. After this, their
input/output behaviour is tested on a separate
functional tester.
Anti-Moisture Coating
The power board contains high voltage DC parts
that are sensitive to moisture. Therefore all po-
wer boards of the Sunmaster QS inverters are
treated with a special anti-moisture coating (so-
called ‘humi-sealing’).
Functional Testing
After the assembly of the control boards on the
power board, the unit is complete. The complete
unit is functionally tested, which means that its
main input/output behaviour is verified. Input
power and current are measured as a function of
the input voltage, to verify the input characteris-
tics. DC input is compared to the AC output to
calculate and verify efficiency. Harmonic beha-
viour and anti-islanding is tested and verified.
Burn-in Testing
Typical to electronics is that for newly produced
units the chance on failure is the highest by far
within the first hours of operation. After this the
failure rate is very low and increases again when
the life time of the unit has expired (typically af-
ter 15 years for Mastervolt products). The higher
failure rate in the first few hours is explained by
the fact that some components might have mate-
rial defects, that only show up when they opera-
te at full load (i.e. not during functional or
ICTesting). The Burn-in Testing is used to solve
this problem: the units are tested for 24 hours at
full load and at higher ambient temperatures
(40-50°C), to literally burn out all component
defects, that still might be present in the pro-
duct. The result is a thoroughly tested product
with a very low failure rate.
Strong Evaluation
One out of every 50 units is tested extensively in
our own laboratory. All production testing is
repeated and extended with even more detailed
testing of components and electrical behaviour.
This is to verify whether production is still wit-
hin its tolerance limits and of constant quality.
The strong evaluation is also used to verify the
effectiveness of all production tests.
Solar Product Manager
Information exchange between all processes in
the organisation is crucial to improve quality
and design. The communication between engi-
neering, service and production is co-ordinated
by a dedicated Solar Product Manager.
The Product Manager collects all test results
from production and strong evaluation testing,
assesses service problems and feeds this informa-
tion back into the engineering and production
process.
11
MASTERVOLT SOLAR SUNMASTER QS SERIES
QUALITY CONTROL
Visual
Inspection
Visual
Inspection
In Circuit
Testing
Programming
& Functional
Testing
Anti Moist
Coating
Assembly
Functional
Testing
Burn In
Testing
In Circuit
Testing
Strong
Evaluation
Power
Boards
Control
Boards
Packaging
Product Manager
Evaluates all information
Burn in testing for 24 hours at 50°C ambient.