Brushed universal motor controller for DC-grids

In this paper we discuss the DC readiness of a typical household appliance, the vacuum cleaner. Traditional vacuum cleaners which are connected to the AC single phase grid contain a brushed DC series motor. For a transition towards a DC grid, one would think that the DC series motor should operate directly from the DC grid. However there are two main problems, which are addressed in this paper, the inrush current and the turn-off of the current using a mechanical switch. A low cost design is proposed that can be applied to transform an AC brushed DC series motor into a DC-ready brushed DC series motor, by adding a power electronics current controller. A prototype was build and placed inside the housing of the vacuum cleaner to validate the design. Experimental tests prove the functionality of the circuit by evaluating the control of the motor current.