True Power Research is a power electronics consultant and provider of custom high voltage power supply designs. High voltage power supply design is one of our specialties. The niche field of high voltage power supply design requires specialized knowledge of the interaction of electric fields with material dielectrics.
Dielectric Withstand Voltage
Dielectric withstand voltage, also known as dielectric strength, is the ability of a material to withstand electric fields in electronic systems and is an important factor in high voltage power supply design. When the dielectric withstand voltage of the material is exceeded, the material is permanently degraded unless the material is renewable such as gases like air. The renewable gases will ionize if the electric field strength becomes great enough. This effect is known as corona discharge and is generally degrading to material reliability and usually precipitates electrical arcing. We are very familiar with the destructive effects of corona — and how to mitigate those destructive effects.
Parasitic Capacitance Charging
Parasitic capacitance is the unavoidable capacitance between conductors located in close proximity, and causes a departure from ideal circuit behavior. Stray capacitance is a subset of parasitic capacitance and generally refers to the capacity of an element to its surroundings. Parasitic capacitance charging becomes an important effect in high voltage power supply designs. The energy required to charge and discharge parasitic capacitances at high voltage and high switching frequency can be a significant part of the converted energy, and this energy must be accounted for in the design. Circuit behavior effects can include, among others, greater than ideal duty cycle to produce a given output voltage, and greatly increased transformer losses.
Leakage Current and Surface Tracking
Leakage current is the undesirable flow of current in the reverse direction through a semiconductor device (referred to as reverse leakage current), or the undesirable flow of current over the surface of an electronic component. In high voltage power supply designs, leakage current becomes much more significant and can be the source of a departure from ideal circuit behavior.
Components are typically fabricated with increased spacing between electrodes to help increase the resistance to leakage current. Additional special measures are often required such as slotting of PCB to greatly increase the creepage distance (the length of the path required for current to travel), and priming and encapsulation to keep component surfaces clean and increase dielectric strength between components.
Failure to keep parts clean usually results in surface tracking which is a failure mode described by flow of electrical current enabled by surface contaminants.
Dielectric Material List
We have designed with dielectric materials such as:
- Air
- Dry air
- Dry nitrogen
- Sulfur hexaflouride (SF6)
- De-ionized water
- Dielectric oils
- Encapsulation compounds
- Insulation tapes
Capabilities
We have provided high voltage power supply designs with output voltage up to and over 100kV, and with power levels up to 50kW and we are ready to assist you with your high voltage power supply design needs.
As part of the design package, you will receive complete documentation including power supply schematics, bills of material, magnetic source control drawings, PCB layout, etc. We are also available to provide in-house prototype testing depending upon our resources to support the testing.
Call or email us today for your requirements for high voltage power supply design.