Variable Frequency Drive Market Size, Share & Covid-19 Impact Analysis, By Type (AC Drive, DC Drive, Servo Drive), By Power Range (Micro, Low, Medium, High), By Application (Pumps, Conveyors, HVAC, Electric Fan, Extruders, Others), By End-User (Food & Beverage, Oil & Gas, Power Generation, Infrastructure, Agriculture, Mining, Others) and Regional Forecast, 2020-2027