Introduction

DANFOSS VACON solar drives convert DC Maximum available DC power from solar panels into 3-phase AC POWER

General Description

With changing solar power, the output frequency changes making the motor run at different speeds which in turn have varying throughputs – flow of water in case of pumps. VACON drives have integrated maximum power point tracking blocks, that continuously draw the maximum power that is available from PV modules. This DC power is converted into 3ph output with varying frequency using Variable Frequency Drive (VFD) that follows the MPPT block. The reason for altering frequency is to match the output power delivered to the motor/pump to the input power from the solar panels. The higher the power, the higher the frequency and therefore higher is the speed/thrust at which the motor is receiving the power. In case of pumps, this changing frequency results in changing RPM of the pump which in turn changes the flow of output water.

Dual Supply Mode

Unique feature of Danfoss inverters is that it allows a ‘simultaneous’ connection of both grid/generator and solar sources for driving the pump. This will draw the maximum power from PV modules and any extra power needed would be drawn from the grid/DG. This allows the non-stop full-speed performance of the system. Alternatively, using an ATS switch, it is possible to switch between AC sources and solar.

Robust IP 66 with Large Capacitor Bank

IP66 4x enclosure allows outdoor installation. The design is optimized for maximum heat dissipation and maintenance-free operation. The largest capacitor bank (plastic foil type – known for its resilience in harsh conditions) prevents sudden shocks due to changing PV power from propagating into the device which may lead to regular trips and in some cases, burnouts – keeping the unit maintenance free offering longer service life. 60C temperature resistance allows almost universal usage in all environments.

Unique 4-Concurrent-Algorithm MMPT

Vacon Drives implements 4 algorithms that are concurrently running to make sure the power drawn from the panels is always the maximum. Feed-forward controller – to follow the solar irradiation, correction controller – to compensate for the changes in temperature, Oscillation damping controller – to manage the smooth transitions between various MPPT points and local Maxima bypass controller – that assures only the overall highest power point is used.