STEP-UP MAXIMUM POWER POINT TRACKER FOR PHOTOVOLTAIC ARRAYS

This paper discusses a new maximum power point tracker (MPPT), which has been devised and tested at the laboratory. This MPPT is a high-frequency set-up dc-to-dc power conditioning unit. Simple and inexpensive analog circuitry is used to continually maximize the true PV array output power rather than maximizing the current or voltage at either the PV array or load. The control circuit is designed such that the actual current and voltage are sensed directly from the PV array. These two signals are then multiplied by a single-chip multiplier. The multiplier output charges or discharges two separate RC circuits of different time constants. These two RC signals are then mixed to set the duty cycle of a pulse width modulated signal to continually track the array maximum power point. This MPPT is simple and inexpensive; and it continuously tracks the true PV array maximum power point regardless of the load type. © 1990.