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From an eco-design context, the total value chain of a product is a long one. It starts with the raw materials, and continues with the design of the product, its production, the transportation to the end customer, the usage, the recycling, and the consequential consumption. At each stage of this life cycle, energy consumption and the production of hazardous waste are considered and the impact quantified. The "unwanted" output consists of emissions such as heat, waste water, greenhouse gases, process chemicals, even more greenhouse gases during transport and usage, and upon recycling even more chemicals and landfill. Quantifying all the impacts in dollars and cents, and summing it all up results in what is called the "lifecycle cost".
It is obvious that in this case less is more. What can be done? Since the biggest impact - at least with energy-using products - is typically to be gained with improved efficiency during operation and standby, a lot of the attention must turn to power supplies and electric motors.
In our daily life, most applications contain either power conversion or motion control subsystems, as the picture below implies. Structuring the application landscape into this dichotomy makes the challenge much easier to address.
The power conversion subsystem basically addresses all AC-DC and DC-DC conversion. Taking a closer look at the topologies used, in the overwhelming majority, a DC voltage is converted to another DC voltage using a switch-mode conversion circuit. Even in the offline power supply, one of the first things to find at the input is a rectifier, so - strictly speaking - an AC-DC power supply is in most cases a DC-DC converter, anyway.
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The motion control subsystem basically works the other way around. Here, a DC input voltage is used to generate alternating waveforms, appropriately shaped to make a motor turn. Sometimes the term DC-AC is used for these systems and other times, it is called frequency inverters. Most motors have three phases, and these inverters have three outputs, again using a switch-mode circuit to create the phase-shifted waveforms for the motor. Three phases really is the minimum to determine a sense of rotation and make the motor start in the desired direction (with the exception of DC brush and switched-reluctance motors).
The key drivers for improvement for all three are improved performance of the switches and control circuits used; the trend to integrate more and more into the power electronics system; and a change in the value chain of manufacturers who produce of this equipment. For instance, many manufacturers consider a power supply as a necessary evil because it is difficult to design, costs space and money and generates heat, but does not add marketable advantages and features to their end product. These manufacturers tend to focus on other aspects of the product more important to them. In these cases, the power supply design must come from somewhere else, and the semiconductor supplier can make a big difference by providing good solution support.
Switch-mode topologies have been around for a long time, but with most of the energy still being lost in the power switches, most of the potential in improving these designs is through improved power switches. It is interesting to note that over time, with characteristics of power switches improving over the decades, the choice of conversion circuits has evolved and changed as well. Today, flyback converters are being used up to 150W and beyond, with the power range up to 400W - that used to be covered with full-bridge converters - now is addressed with half-bridge converters. Not to forget the improvements in control circuits and passive components, where new control schemes and tighter tolerances have allowed a widespread use of resonant topologies, improving efficiency and reducing electromagnetic emission further.
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