Product specifications

ManualsBrandsVoltmaster ManualsPortable GeneratorSG-Series

Multiple Solar inputs with

multiple MPPTrackers

The QS3200 & 5000 are equipped with resp.

two and three MPPTracked solar inputs.

This makes it possible to connect strings

with different number of modules in series,

different orientations or different module

types. With this feature you can connect

virtually any number of modules or any

array configuration to the QS inverters. If

necessary the QS3200 and QS5000 can also

be configured to have one single input.

Intelligent control

The QS inverters are controlled by the

central processor on the control board. The

processor controls the Mosfets and IGBTs

in the input and output converters through

dedicated PWM chips, MPPTracker con-

trol, self diagnostics and communication

with the LED bar, QS Display and QS

Data Bus.

QNS/ENS redundant

grid monitoring

The presence of the grid is detected using

redundant measurement of grid voltage

and frequency (QNS). Redundant means

that two independent measuring circuits

and micro-controllers measure the grid

voltage and frequency independently.

When one circuit fails, the remaining cir-

cuit will still do the job. In case of grid fai-

lure the inverter is switched off in the same

redundant way: by a double pole mechani-

cal relay and by means of the solid state

switches (Mosfet and IGBT) on the grid

side of the inverter. The ENS versions of

the grid monitoring add the measurement

of the grid impedance to the list. The grid

impedance is measured using a capacitor

that is switched in parallel to the grid for

one cycle. During this cycle the capacitor

draws and feeds back a certain amount of

‘blind’ current. This amount of current is a

measure for the grid impedance. This tech-

nology uses little power and has no influen-

ce on the harmonic behaviour on the grid

side. The measurement protocol incorpo-

rates features to deal with interference of

several ENS units performing measure-

ments on the same grid.

The switch off impedance level can be set

by a jumper (0,5 or 1 Ω).

Earth fault detection

The Solar array works with high DC vol-

tages in a ‘floating’ configuration. This

means that none of the solar connections

are grounded. In such systems, the first

ground connection is not dangerous, since

it carries no current (no closed loop). The

second earth connection however closes the

loop through ground and can be dange-

rous. The QS inverters are equipped with

earth fault detection, detecting the first

ground fault, switching the inverter off. It

is indicated to the user that the system has

become potentially dangerous (i.e. when a

second earth fault is created) and the sys-

tem should be checked (indication in the

LED Bar).

Thermally guarded

lightning varistors

To protect the inverter from lightning

induced voltage spikes, both solar and grid

connections are protected by varistors. The

proper operation of the varistors is checked

by continuous monitoring of the tempera-

ture. Possible failure of these varistors is

indicated to the user through the LED bar

indicator. These varistors are located in the

connection compartment for easy replace-

ment in case of failure.

Communication interface

All communications of the QS range are

based on the RS485 QS Data Bus. This

means that it is possible to connect one or

several units with one or several options,

such as display(s), computer(s), datamoni-

tor(s) or other devices in a straight forward

way. You just extend the QS Data Bus to

the new unit or option and connect it. The

protocol solves all configuration and com-

munication issues. A Sunmaster QS unit is

connected to the QS Data Bus using a sim-

ple plug-in communication interface,

which is also used for the communication

with the integrated display. More informa-

tion on the extensive communication sche-

me can be found on pages 6 and 7.

MASTERVOLT SOLAR SUNMASTER QS SERIES

TECHNOLOGY

3 4

point of the array.

Static MPPTracker

Typical for the Mastervolt products is the

simple but stable and reliable MPPTracker

algorithm. The characteristics of a PV ar-

ray exhibit a strong dependency on irradia-

tion, temperature, cell type, shading, cell

defects or mismatch. Especially at start up

(low irradiation) and strongly fluctuating

circumstances (cloudy days), dynamic trac-

kers might show instable and inefficient

behaviour. Mastervolt solved this by imple-

menting a static MPPTracker, that calcula-

tes the MPP set point from the measured

open circuit voltage of the array (every two

seconds). The open circuit voltage of the

array is well defined under all circumstan-

ces, so the inverter can always set a stable

MPP set point, resulting in stable and

reliable operation.