Optimized control of a power converter in response to load conditions

摘要

A power converter and a method of operating the same is described, for use in a power conversion system that is capable of receiving power from various sources, including renewable sources, for delivering power to a load. Power type detection circuitry is provided for identifying the type of power source at the input of each power detector, based on attributes of the time-varying power received. The power converter is constructed of a boost stage followed by a galvanically isolated DC-DC converter stage. If a renewable input power source is detected, the boost stage is controlled to operate at a maximum power point, and the DC-DC converter stage is operated in an open loop manner when load exceeds available power at input. The load falls below available input power, the boost stage is controlled to regulate its output voltage and DC-DC converter stage is also placed under closed loop control. If the AC grid is detected as the input power source, the boost stage is controlled to attain maximum power factor, and the DC-DC converter stage is placed under feedback control of the output voltage.

主权项

1. A power converter system for producing a direct current (DC) output voltage from one or more of a plurality of power sources, comprising:
a plurality of isolating power converters, each power converter of the plurality of isolating power converters comprising:
a power converter circuit having an input and an output, the power converter circuit configured to receive input power from a power source at the input and to provide DC power at the output;a boost stage configured to generate a bus voltage from the input power received at the input of the power converter circuit;a converter stage having an input configured to receive the bus voltage from the boost stage and an output galvanically isolated from the converter stage input, wherein the converter stage is configured to generate DC power at the converter stage output from the bus voltage; andcontroller circuitry coupled to the power converter circuit and configured to receive the bus voltage, the controller circuitry configured to operate the power converter circuit at an operating point selected to facilitate maximizing power converted from the power source when the bus voltage is above a predetermined threshold, the controller circuitry further configured to control the voltage at the output of the power converter circuit according to a setpoint voltage when the bus voltage is below the predetermined threshold, wherein the controller circuitry comprises:
a pulse width modulator having an output coupled to the boost stage;a maximum power point tracking controller having: i) a first input coupled to power type detection circuitry, ii) a current sense input coupled to an input of the boost stage, and iii) an output;one of power factor compensation circuitry and feedback control circuitry, the one of power factor compensation circuitry and feedback control circuitry having: i) a first input coupled to the input of the boost stage, ii) a second input coupled to an output of the boost stage, and iii) an output; andcontrol mode select circuitry having an input coupled to the boost stage to receive the bus voltage, the control mode select circuitry configured to couple the output of the maximum power point tracking controller to an input of the pulse width modulator when the bus voltage is above the predetermined threshold, and configured to couple the output of the one of power factor compensation circuitry and feedback control circuitry to the input of the pulse width modulator when the bus voltage is below the predetermined threshold; and wherein the outputs of the plurality of isolating power converters are connected together for coupling to a load.