Students: Thomas Carley Luke Ketcham Brendan Zimmer Advisors: Dr. Woonki Na Dr. Brian Huggins Bradley University Department Of Electrical Engineering 2/28/12

Presentation Outline Brief Summary of Project Goals Functional Description, System Block Diagram, and Performance Specifications Implementation, Construction, and Testing Schedule and Milestones

Project Summary Supplies DC and AC Power Photovoltaic Array Boost Converter to step up PV voltage Maximum Power Point Tracking DC-AC converter for 120Vrms 60Hz LC filter

System Block Diagram

DC Subsystem Requirements The boost converter shall accept a voltage from the photovoltaic cells. – The input voltage shall be 48 Volts. – The average output shall be 200 Volts +/- 25 Volts. The voltage ripple shall be less than 20 Volts The boost converter shall perform maximum power point tracking. – The PWM of the boost converter shall be regulated based on current and voltage from the PV array. – The efficiency of the MPPT system shall be above 85%.

AC Subsystem Requirements The AC side of the system shall invert the output of the boost converter. – The output of the inverter shall be 120 Volts RMS. – The output shall be 60Hz +/- 0.1Hz. The inverter output shall be filtered by a LC filter. – The filter shall remove high switching frequency harmonics. – Total harmonic distortion of the output shall be less than 15%.

Boost Converter Test Boost Converter 10V to 30V

Boost Converter Output Voltage (V)

Boost Converter Output Current (A)

Boost Converter 48V – 200V Soft Start

Boost Converter Without Soft Start (V)With Soft Start (V)

Boost Converter Without Soft Start (A)With Soft Start (A)

Boost Converter Output VoltageInductor Current

Boost Converter Future Work RC snubber circuit to reduce voltage spikes Adjustment of load resistor value Adjustment of output capacitor Implementation of soft start either through – Switched Resistor – Slowly increasing duty cycle with DSP

Power Supplies 120Vrms 60Hz input from wall 15V, 5V, and 3.3V output Consists of Transformer, Diode Rectifier, 470uF capacitor, and voltage regulators Needed for Gate Drivers, Op Amps, Sensing ICs, and other logic devices

Power Supply

Implementing MPPT with DSP Voltage Divider Current Sensor Simulink Modeling for TMS320F2812

Voltage Divider

Current Sensing Current Sensor thru current Current Sensor Vout A2.513 V

Current Sensing Circuit

Simulink Model

Single Phase Inverter Inverter H-Bridge and gate drives Tested with complementary PWM signals To do: Add isolation Add logic compatibility circuitry

Inverter Experimental Results V source = 10 V R load = 496 Ω

Sinusoidal PWM The magnitude of a triangle carrier signal is compared to a sinusoidal reference If Vreference > Vcarrier PWM signal = high If Vreference < Vcarrier PWM signal = low

Sinusoidal PWM – Simulink

SPWM – Simulink Results

LC Filter Second order LC filter transfer function: G(s) = 1/(L*C*s^2+1)

LC Filter - Simulation

Simulation Results Unfiltered frequency spectrum Filtered frequency spectrum

Schedule and Milestones

Questions?

PV data collection Mostly sunny, with a high near 36. West southwest wind between 8 and 11 mph, with gusts as high as 15 mph.

Boost Converter Current Before DiodeDrain Voltage