Highly Reliable and Compact Universal Power Converter

INV-16060

 

In the modern era, electrically-powered devices have become ubiquitous. A power source for an electrically-powered device often has a set of static characteristics such as a voltage level, a minimum or maximum current, and a frequency that do not align with those required by the device and thus a power convertor is required to convert to have characteristics compatible with the electrical device.

Power convertors may utilize switches typically in the form of bipolar transistors or field effect transistors (FETs) or insulated gate bipolar transistor (IGBT) to control the type of power conversion (i.e. DC-AC, AC-AC, AC-DC, DC-AC), the voltage change, and the frequency change. While such power convertors provide more universal control over the type of power conversion, a single switch failure may prevent the power convertor from operating correctly.

 

This invention is related to a novel capacitive‑link universal power converter. A modified configuration based on this converter contains fewer switches.The configuration has fewer switches, increasing the power density and reliability. The link capacitor is still the main power transfer component and will be charged from the two input phases and then it will be discharged into two output phases. In this soft switching configuration, there is a resonating mode between each two power transfer modes.

 Some power converters utilize switches— typically in the form of bipolar transistors or field effect transistors (FETs) or Insulated Gate Bipolar Transistor (IGBT)— in order to control the type of power conversion (e.g. DC-DC, AC-AC, AC -DC, and DC-AC), the voltage change, and the frequency change, among other power characteristics. These switches, when coupled with diodes, can be configured to facilitate rectification, inversion, or simply allow current to flow without changing its frequency. These power converters typically involve one or more reactive components that facilitate the change in voltage in a similar manner as buck or boost converters. While such power converters provide a more universal control over the type of power conversion, the switches increase the failure rate of the power converter. Depending on the desired power conversion, a single switch failure may prevent the power converter from operating correctly. 

A universal power converter of the present application may include a link stage between an input stage and an output stage that operates at a higher frequency than the frequency of the input power source. As a result, a more compact capacitor may be used, thus reducing the size of the power converter. In some embodiments, the link stage may be a partially resonant link that permits zero current switching (ZCS). ZCS operation may reduce switching losses during operation. Universal power converters of the present application utilizing ZCS may be implemented using naturally commutated switches, such as silicon controlled rectifiers (SCRs), instead of transistor switches. Such power converters utilizing SCRs may be more reliable than power converters utilizing transistor switches. Additionally, control circuitry required to operate such power converters may be simplified. Accordingly, a more compact, efficient, and reliable universal power converter may be achieved. 

 

New topology requires smaller number of controllable switches; thus:

- Lower cost

- Higher power density

- Longer lifetime 

- Faster and simpler

- More reliable

 

Energy systems installation

- Reduce the shipping cost

- Also increase the lifetime of the convertors

- Reduces the cost for repair and replacement of the convertors

 

- License

- Partnering

- Research collaboration