Noise & Distortion

The majority of power quality problems are a result of ripple, noise, distortion or transients which are so prevalent on many power circuits that industry in general is adapting regulatory standards as to acceptable limits of electrical pollution.

AC ripple is a result of the fundamental power conversion frequency within a rectifier. Any significant AC ripple applied to batteries will result in decreased battery life, charging inefficiency and battery heating.

Rectifier output and inverter input filtering must keep ripple to a minimum and not rely on batteries themselves to act as a ripple filter to reduce the DC load ripple, as some power converters do.

Ripple
Fundamental frequency AC voltage or current coming from inside a rectifier and imposed upon output DC voltage or current.

Staticon rectifier outputs and inverter inputs are fully filtered to reduce AC ripple to 1% or less, even without a battery connected.

Electrical noise is of particular concern in telecom DC power systems due to the sensitive nature of telecom networks and equipment.

Again, electrical noise is a result of rectifier power conversion with faster switching methods being inherently noisier than slower (low frequency) switching methods.

Electrical Noise
Aggregate sum of higher-than-fundamental frequency AC voltage or current coming from inside a power converter and imposed upon DC voltage or current.

Staticon rectifier outputs and inverter inputs are fully filtered to reduce AC ripple to 1% or less, even without a battery connected.

Rectifier input current distortion is the TDD (total demand distortion) of the AC input current. TDD is a result of the power conversion process and is reflected back into the AC prime power supply.

TDD is AC supply pollution and can adversely affect any upstream loads. Many high frequency conversion technologies produce TDD in the order of 50% to 150% due to their fast and abrupt switching characteristics.

Inverter AC output voltage distortion known as total harmonic distortion (THD) detracts from perfect sinusoidal AC waveforms. THD is due to the DC-AC power conversion process and varies according to the conversion technology used. Some inverters even produce an alternating square wave, step-wave or quasi-sine wave output which deviates substantially from a true sine wave and can adversely affect many AC loads.

Distortion
Any deviation from, or extraneous component imposed upon, a true sinusoidal voltage or current waveform.

Staticon line conditioners and inverters produce a true sine wave output with a guaranteed THD of less than 3% (phase-to-phase). The greater the noise and distortion produced by a power converter, the greater the requirement for unit input and output filtering to reduce this noise and distortion to an acceptable level.

Ripple, noise and distortion produced by power conversion equipment is due to internal power semiconductor switching. Different power conversion technologies produce different levels of ripple, noise and distortion. High frequency conversion technologies generally produce greater amounts of distortion and noise than lower frequency conversion technologies due to the comparatively faster and more abrupt switching characteristics of these techniques. Many sophisticated, high frequency power conversion technologies require filtering of such complexity that it accounts for over half of the power converter components and cost. Remember, that as sophistication increases, reliability and field serviceability decrease.