WEG CFW11 Applications Manual page 11

Photovoltaic Water Pumping System
2 PHOTOVOLTAIC WATER PUMPING SYSTEM
This document presents information necessary to configure all the functions of the frequency inverter CFW11
applied to photovoltaic water pumping systems. For more detailed information on the function of expansion
and communications accessories, refer to the following manuals:
■ CFW11 Frequency Inverter Documentation;
■ Solar Pump Drive Installation Guide;
■ CFW11 SoftPLC Manual;
■ CFW11 Programming Manual;
These files are available on the WEG's website - www.weg.net.
2.1 OVERVIEW OF THE CFW11 IN PHOTOVOLTAIC SYSTEMS
The frequency inverter CFW11 is a high-performance converter AC/DC and AC/DC that allows a speed and
torque control of induction three-phase motors. The frequency inverter CFW11 also features PLC
(Programmable Logic Controller) through the SoftPLC feature (integrated).
The function of the CFW11 in photovoltaic water pumping systems is to convert energy generated by
photovoltaic modules into alternating form, and to apply this energy in the activation of water pumps, according
to Figure 2.1.
Where:
(1) Solar photovoltaic plant
(2) Frequency Inverter CFW11 WEG
(3) Water pump
(4) Water tank
2.2 GENERAL CHARACTERISTICS OF THE SOLAR PUMP
The main characteristic of the Solar Pump Drive developed for the CFW11 inverter SoftPLC function is the
control of one pump using a frequency inverter supplied by a photovoltaic system, thus allowing control of the
speed of the pump.
Which is notable for the following characteristics:
■ Acceleration and deceleration ramps for the pump driven by inverter;
■ Maximum and minimum speed limits for the pump driven by inverter;
■ Selection the manual control mode or automatic. If the control is in manual mode the control setpoint will be
speed, if it is in automatic the control setpoint will be pressure;
■ Selection of the control setpoint via logical combination of the two digital inputs (maximum of 4 setpoints);
■ Selection of the control process variable via analog input AI1;
■ Selection of the engineering unit and range of the control process variable sensor via CFW11 parameters;
■ Voltage setpoint Vdc minimum and maximum;
■ Gain, offset and filter adjustments for the control signals via analog inputs;
■ PID controller gains setting of the pressure control;
■ PID controller gains setting of the voltage control;
■ Enable or not of the sleep mode with the PID controller enabled;
■ Wake up/Start level mode to activate the pump;
Figure 2.1 – Block Diagram of a photovoltaic pumping system
Solar Pump Drive | 11