Switching converter using partial power processing

A power conversion circuit comprising:

• a first converter stage configured to provide a constant DC bus voltage;
• a second converter stage that is configured to receive the DC bus voltage and to generate an output voltage therefrom, and
• a controller;
• wherein the second converter stage includes at least a first main branch, a second main branch and a partial power branch,
• wherein the first and the second main branch are each configured to provide, at their outputs, a respective first voltage from the DC bus voltage based on a fixed conversion ratio,
• wherein the second converter stage includes a switching circuit that is configured to connect the outputs of the first and second main branch either in series or in parallel,
• wherein the partial power branch is configured to provide, at its output, an adjustable second voltage from the DC bus voltage and wherein the partial power branch is coupled to the first and second main branches so that the second voltage adds to a common voltage provided by the first and second main branches to generate the output voltage, and
• wherein the controller is configured, in order to set the output voltage to a desired value, to configure the switching circuit in order to connect the first and second main branch either in series or in parallel and control the partial power branch to adjust the second voltage.

A method comprising:

• generating a DC bus voltage using a first converter stage of a power conversion circuit;
• generating, using a second converter stage of a power conversion circuit, an output voltage from the DC bus voltage, wherein the second converter stage includes at least a main branch and a partial power branch;
• wherein generating the output voltage includes:
• generating a first voltage from the DC bus voltage using a first DC transformer circuit with a fixed conversion ratio in the main branch;
• generating, in the partial power branch, a second voltage from the DC bus voltage, wherein the first voltage and the second voltage are superposed to generate the output voltage;
• and
• wherein the DC bus voltage and the second voltage are adjusted such that the output voltage is set in accordance with a desired value.