Consumer attitudes are changing and the energy ratings of domestic appliances are becoming an increasingly important aspect of modern purchasing decisions - whereas previously it would have come a long way down the list (somewhere below, features, price, aesthetics, etc.). For such items to attain high scores in relation to their energy rating, variable speed operation is necessary (in contrast to the less sophisticated 'all or nothing' approach of the past). This allows great efficiency levels to be realised, with a number of different benefits subsequently being derived.
Firstly by drawing less electricity, the energy that needs to be generated to run them can be reduced - leading to less impact on the environment (in terms of lower CO2 emissions and a smaller quantity of fossils fuel reserves being used up in the process). Then there are the reduced utility bills to take into consideration. Reliability is also improved, resulting in longer working lifespans. Finally, variable speed appliances offer quieter running, which is a very attractive trait for the majority of consumers.
Manufacturers of refrigerators, washing machines, dish washers and air conditioning units are all seeing the value of incorporating energy-saving variable speed motors into their products. Through the specifying of simple brush-less DC (BLDC) motors it has been possible to mitigate a reasonable proportion of the extra costs associated with developing/producing variable speed drives (which are obviously not as straight forward as fixed-speed drives they are replacing). Permanent magnet synchronous motors (PMSM) controlled using sinusoidal waveforms that simple BLDCs require, seem destined to be the way forward - satisfying market demands for still further improvements. The latest generation of high voltage intelligent power devices (HV-IPD) present engineers with heightened levels of flexibility when looking to implement synchronous motor control systems.
To learn about the progress Toshiba has made in developing HV-IPDs (based on advanced semiconductor process technologies) for sine-wave control, you can download its new white paper on the subject. Just go to: