Power inverter with reduced body diode conduction

A method for controlling a power inverter, the method comprising:

• providing a first voltage to a first metal-oxide-semiconductor field-effect transistor (MOSFET) which is coupled to an inverter node;
• providing a second voltage to a second MOSFET which is coupled to the inverter node, wherein the inverter node is coupled to a first output terminal via an inductor, wherein the first output terminal is an alternating current (AC) terminal;
• generating an output voltage at the first output terminal, wherein the output voltage is an AC voltage;
• providing, by a current sensor coupled to the inductor, a sensor signal that is a function of an inductor current that flows through the inductor;
• comparing the sensor signal with a first limit value which is positive with respect to a reference potential, wherein the comparing is performed by a comparator arrangement coupled to an output of the current sensor;
• comparing, using the comparator arrangement, the sensor signal with a second limit value which is negative with respect to the reference potential;
• switching, by a control arrangement, the first MOSFET from a conducting state to a non-conducting state and the second MOSFET from a non-conducting state to a conducting state in case the sensor signal rises above the first limit value, the control arrangement comprising a modulator and a voltage regulator with an input which is coupled to the first output terminal and an output at which a control signal is provided;
• switching, by the control arrangement, the first MOSFET from the non-conducting state to the conducting state and the second MOSFET from the conducting state to the non-conducting state in case the sensor signal falls below the second limit value;
• providing, by the voltage regulator, the control signal with a pulse duration which depends on a comparison of the output voltage with a desired alternating current output voltage;
• and
• controlling, by the modulator, the first MOSFET and the second MOSFET as a function of the control signal and at least one output signal of the comparator arrangement, the modulator comprising:
• a first input coupled to the output of the voltage regulator;
• a second input coupled to the comparator arrangement;
• a first output coupled to a control terminal of the first MOSFET;
• and
• a second output coupled to a control terminal of the second MOSFET.

A power inverter, comprising:

• a first and a second input terminal and a first output terminal;
• an inverter node;
• a first metal-oxide-semiconductor field-effect transistor (MOSFET) which couples the first input terminal to the inverter node;
• a second MOSFET which couples the second input terminal to the inverter node;
• an inductor that couples the inverter node to the first output terminal;
• a current sensor coupled to the inductor and configured to provide a sensor signal that is a function of an inductor current that flows through the inductor;
• a comparator arrangement coupled to an output of the current sensor and configured to compare the sensor signal with a first limit value, wherein the first limit value is positive with respect to a reference potential;
• and
• a control arrangement which is connected on its output side to a control terminal of the first MOSFET and to a control terminal of the second MOSFET and is configured to switch the first MOSFET from a conducting state to a non-conducting state and the second MOSFET from a nonconducting state to a conducting state in case the sensor signal rises above the first limit value,
• wherein the first output terminal is an AC terminal,
• wherein the power inverter is configured to generate an output voltage at the first output terminal, and
• wherein the output voltage is an AC voltage,
• wherein
• that the comparator arrangement is configured to compare the sensor signal with a second limit value which is negative with respect to the reference potential,
• wherein the control arrangement is configured to switch the first MOSFET from the nonconducting state to the conducting state and the second MOSFET from the conducting state to the non-conducting state in case the sensor signal falls below the second limit value, and
• wherein the control arrangement is configured:
• to count a number of cycles during which the sensor signal rises above the first limit value or falls below the second limit value,
• to compare the number of cycles with a predetermined cycle value, and
• to set the first and the second MOSFET in the non-conducting state in case the number of cycles is higher than the predetermined cycle value,
• wherein the predetermined cycle value is at least one.