Phase Converters & Power Factor
Phase Converter Efficiency
Installing a Phase Converter
Rotary Phase Converters
Static Phase Converters
VFDs as Phase Converters
     • Harmonic Distortion
Three-Phase Motors
Phase Converters & Voltage Balance
Phase Converter Applications
     • Submersible Pumps
     • Woodworking Equipment
     • Dual Lift Stations
     • Phase Converters & Welders
     • Phase Converters & CNC Machines
     • Phase Converters & Air Compressors
     • Phase Converters & Elevators
     • Phase Converters & Wire EDM
     Phase Converters & HVAC
Phase Converters & Transformers
     • Step-up Transformers
     • Buck-Boost Transformers
     • Isolation Transformers
Phase Converter Experts
Digital Phase Converters
Regenerative Power
Three-Phase Power
     • Delta vs. Wye Configured Power
Motor Starting Currents

Digital Phase Converters


Digital Phase ConverterDigital phase converters are a recent development in phase converter technology that utilizes proprietary software in a powerful microprocessor to control solid state power switching components.  This microprocessor, called a digital signal processor (DSP), monitors the phase conversion process, continually adjusting the input and output modules of the converter to maintain perfectly balanced three-phase power under all load conditions.

Like rotary and static phase converters, a digital phase converter generates a third voltage, which is added to L1 and L2 of single-phase service to create three-phase power.  There the similarity ends.

A process called double-IGBT conversion generates the third voltage. Double conversion means that AC power from the utility is converted to DC, then back to AC. The power switching devices used in this process are insulated gate bipolar transistors (IGBT).

The input module, or rectifier, consists of IGBTs in series with inductors. Operating at a

switching frequency of 10,000 Hz, the IGBTs are controlled by software in the DSP to draw current from the single-phase line in a sinusoidal fashion, charging capacitors on a constant voltage DC bus. Because the incoming current is sinusoidal, there are no significant harmonics generated back onto the line as there are with the crude rectifiers found in most VFDs. The electronic power factor correction on the input module also corrects the power factor of any inductive loads so that the utility sees a system that operates at near unity power factor. The power factor correction makes digital phase converters very efficient and utility friendly

The output module, or inverter, consists of IGBTs that draw on the power of the DC bus to create an AC voltage. A voltage created by power switching devices like IGBTs is not sinusoidal. It is a pulse-width-modulated (PWM) waveform very high in harmonic distortion. This PWM voltage is then passed through an inductor/capacitor filter system that produces a sine wave voltage with less than 3% total harmonic distortion (standards for computer grade power allow up to 5% THD). By contrast, VFDs generate a PWM voltage that limits their versatility and makes them unsuitable for many

applications. Software in the DSP continually monitors and adjusts this generated voltage to produce a balanced three-phase output at all times. It also provides protective functions by shutting down in case of utility over-voltage and under-voltage or a fault. With the ability to adjust to changing conditions and maintain perfect voltage balance, a digital phase converter can safely and efficiently operate virtually any type of three-phase equipment or any number of multiple loads.

The solid state design results in a relatively small package with no moving parts except for small cooling fans.  The converters are very efficient, operating at 95-98% efficiency.  When the converter is energized with no load, it consumes very little power.

Digital phase converters are a patented technology developed by Phase Technologies, LLC, who is the only manufacturer of true digital phase converters.