The up-front investment in a custom solution can pay off if your power electronics cost is above $0.50/Watt, if you have reliability or performance issues, or if you are using off the shelf devices that are “overkill” for your application. A custom solution is also beneficial if you have unique requirements not met by commodity products – e.g. an unusual power supply voltage; a load or power source that has unique characteristics that a standard power supply, inverter, or converter cannot deal with satisfactorily. Another advantage of a custom solution is taking advantage of advanced power conversion topologies (such as multi-level or resonant topologies) that may provide a significant cost or performance advantage.
Yes, sometimes. There is a large variety of power supplies, inverters, drives, etc. available. If a commodity power supply or other product meets your needs, and has a diverse market for its applications, then it will likely be lower cost than a custom solution. However, sometimes you need to modify the product, use additional components, or get a product that is over rated or has a number of features you don't use. In these cases there may be cost savings in designing something that precisely meets your needs. Even if an off the shelf power supply meets your requirements, the cost may still be high if the product has a limited market and does not enjoy the advantages of economies of scale.
Traditional power electronics topologies are well known, reliable, and have been perfected over many years of application. However, it is possible that your application has outgrown traditional topologies. Like all technologies, power electronics is constantly advancing, with new devices and topologies. For example, multi-level inverter topologies are used to build higher voltage inverters, often with lower losses, lower cost, and better performance than with a standard 2 level topology. Resonant conversion was a key technology for many of the successful entries in Google’s Littlebox challenge. If size or power losses are a significant problem in your application, consider resonant technology as a potential solution.
When purchased in sufficient volume, power supplies, inverters, and other devices rated 1000W and higher can be obtained for as low as US$0.10/Watt. In lower volume applications, $0.20/Watt - $0.50/Watt is a reasonable target price to meet. Although $1/Watt has often been given as a guideline, this cost is only justified if the power electronics is highly specialized and in unique application. If you are paying more than $0.50/Watt, it is likely a custom design could save you money.
Reflected waves are an artifact resulting from high speed switching in VFDs. As drive technology advances, opportunities for development of reflected waves actually increase. Please refer to this presentation for more details on causes and possible solutions. Contact us if you would like to discuss your particular situation.