CCM operation analysis of a family of converters for power recycling during the burn-in test of synchronized UPSs

This paper analyzes the CCM (continuous current mode) operation of the family of power converters proposed for power recycling during the burn-in test of synchronized UPSs with sinusoidal output voltage. Though the DCM (discontinuous current mode) operation has the advantage of simplicity and no need of active control to impose the sinusoidal currents, the CCM operation reduces the current peak in the semiconductors and the filters volume. Another important characteristic of CCM operation is: by imposing a sinusoidal current in the DC/DC converter inductance, sinusoidal currents are naturally obtained at the input and output of the converter. So, the currents drained from the UPS and injected into the utility grid present a low total harmonic distortion (THD) and high power factor. The circuit operates at constant frequency, the control is based on the average current value and can be performed by a power factor controller IC. Circuit operation, mathematical analysis, design example and experimental results of a 700 W power recycler are provided in the paper.