FPGA-based startup for AC electric drives: Application to a greenhouse ventilation system

• A startup algorithm is design for AC synchronous machine.
• The algorithm is implemented with a custom VHDL design.
• The FPGA-based solution yields to a smooth acceleration ramp for the rotor velocity in the motor.
• The AC synchronous machine is applied as a fan drive in a greenhouse.
• The AC synchronous machine presents smooth transient currents.

In this work, a simplified startup method for AC synchronous machines is solved by means of a simplified algorithm based only in feeding the AC synchronous machine with stator voltages with a ramp frequency. The implementation of the algorithm along with the Space Vector Pulse Width Modulation technique is carried out by means of a Field Programmable Gate Array (FPGA) device, where Very High Speed Integrated Circuit, Hardware Description Language (VHDL) modules are custom designed. Experimental results were carried out for the ventilation of a greenhouse. The fan drive is turned on according to an existing control strategy designed for an optimal ventilation of the greenhouse. The designed algorithm with custom VHDL modules yields to a great performance for the fan drive in terms of smooth transient currents. The proposed algorithm was also implemented with an embedded microprocessor or softcore in an FPGA device for comparison purposes, yielding to same results. But in the case of optimal utilization of FPGA resources and the speed of execution of the algorithm, the VHDL modules custom design showed the best results.