SAE J2894-1:2019 pdf free

SAE J2894-1:2019 pdf free.Power Quality Requirements for Plug-In Electric Vehicle Chargers
If voltage distortion is negligible, total power factor is equal to the product of total power factor and distortion power factor.Total power factor, which is the ratio of real power to apparent power at the fundamental frequency (50/60 Hz), is a measure of the phase shift that occurs between line voltage and line current when the AC line is loaded with a linear load having reactive characteristics, such as an AC motor. The line current is sinusoidal in shape, but either leads or lags the line voltage in phase (see Figure 1).
Current distortion is the ratio of fundamental current to total rms current. The line current distortion is normally the result of non-linear loading of the AC line. Most switching power supplies, except those that incorporate active power factor correction, use full wave bridge rectifiers with capacitive input filters to perform AC to DC conversion from the line (see Figure 2). The rectified AC peak charges the input capacitor to produce a DC voltage nearly equal to the peak line voltage. Because the capacitor is peak charged, the diodes in the bridge rectifier are reverse biased for most of the AC sine wave, forward biasing only near the peak of the line voltage where V(line) exceeds V(cap) + 2 X V(diode). The resulting currents are highly distorted from the ideal sine wave, and contain harmonics of the fundamental line frequency.
It is desirable for any current drawn from the AC line to have a fundamental frequency equal to the line frequency (50/60 Hz) with no harmonic distortion. This is because only fundamental current contributes significantly to true power delivery.Harmonic currents do not contribute to true power because the product of the undistorted line voltage and the harmonic currents, averaged over one full cycle of the AC line, is always equal to zero. In short, harmonic currents that flow on the AC line contribute nothing to true power delivery. They simply heat the wire and, in so doing, waste energy.SAE J2894-1 pdf free download.