Improvements to the energy efficiency levels of inverter motor drives are making them increasingly attractive in applications where the power budget needs to be reined in - so that more stringent environmental guidelines can be adhered to. These applications include small HVAC (heating, ventilation and air conditioning) systems, light industrial drives and certain domestic appliances. The price tags normally associated with the inverter drives for these sort of tasks can be fairly high however, plus the overall size of the solution can be substantial. These characteristics are proving very restrictive in what can be highly competitive, low margin business areas, where board real estate is at a premium. The problems stem from the fact that conventional methodologies for addressing key functions like optical isolation, over-current protection and fault feedback all contribute to ramping up the costs involved.
Over-current protection mechanisms have generally been based on large, cumbersome current transformers that take up space and are inherently expensive, or current-sense resistors that result in greater power losses due to the load current that flows through the resistor. Other protection and fault detection elements require the use of complex circuitry. Demand is therefore growing for a new breed of smart gate-driver couplers - incorporating compact, power-efficient and cost-effective protection mechanisms that will help to make inverter drives more affordable, streamline their design, reduce the component count and save valuable space too.
Toshiba has created a comprehensive white paper on this subject. You can download it for free here: