Inverter with independent current and voltage controlled outputs

A bimodal inverter operative to convert DC power from a battery to a voltage-controlled AC output, comprising:

• a first half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery;
• an inductor connected between a node between the switches of the first half-H-bridge and a neutral AC output terminal;
• a second half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery;
• a first damped low-pass filter connected between a node between the switches of the second half-H-bridge and a first voltage-controlled AC output terminal;
• and
• a controller operative to control the first half-H-bridge to alternately connect the positive and negative battery terminals to the neutral AC output terminal through the inductor to provide an electronic center-tap of the battery;
• and
• wherein the controller is further operative to control the second half-H-bridge to alternately connect the positive and negative battery terminals to the first voltage-controlled AC output terminal through the first damped low-pass filter according to a bit-density modulation stream of binary bits chosen to approximate a sinewave voltage waveform.

A bimodal inverter operative to convert DC power from a battery to a current-controlled AC output, comprising:

• a first half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery;
• a first inductor connected between a node between the switches of the first half-H-bridge and a neutral AC output terminal;
• a second half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery;
• a second inductor connected between a node between the switches of the second half-H-bridge and a current-controlled AC output terminal;
• and
• a controller operative to control the first half-H-bridge to alternately connect the positive and negative battery terminals to the neutral AC output terminal through the first inductor to provide an electronic center-tap of the battery;
• and
• wherein the controller is further operative to control the second half-H-bridge to alternately connect the positive and negative battery terminals to the current-controlled AC output terminal through the second inductor according to a bit-density modulation stream of binary bits chosen to approximate a sinewave current waveform.

A bimodal inverter operative to convert DC power from a battery to either or both of a current-controlled AC output and a voltage-controlled AC output, the AC outputs sharing a neutral output terminal, comprising:

• a first half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery;
• a first inductor connected between a node between the switches of the first half-H-bridge and the shared neutral AC output terminal;
• a second half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery;
• a damped low-pass filter connected between a node between the switches of the second half-H-bridge and a voltage-controlled AC output terminal;
• and
• a third half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery;
• a second inductor connected between a node between the switches of the second half-H-bridge and a current-controlled AC output terminal;
• and
• a controller operative to control the first half-H-bridge to alternately connect the positive and negative battery terminals to the shared neutral AC output terminal through the inductor to provide an electronic center-tap of the battery;
• wherein the controller is further operative to control the second half-H-bridge to alternately connect the positive and negative battery terminals to the voltage-controlled AC output terminal through the damped low-pass filter according to a bit-density modulation stream of binary bits chosen to approximate a sinewave voltage waveform;
• and
• wherein the controller is further operative to control the third half-H-bridge to alternately connect the positive and negative battery terminals to the current-controlled AC output terminal through the second inductor according to a bit-density modulation stream of binary bits chosen to approximate a sinewave current waveform.

A method of controlling a bimodal inverter operative to convert DC power from a battery to either or both of a current-controlled AC output suitable for backfeeding power to an electric utility grid and a voltage-controlled AC output suitable for directly powering AC loads, comprising:

• monitoring an AC current at the current-controlled AC output;
• comparing the monitored current to a desired current waveform;
• if the monitored current deviates from an instantaneous value of the desired current waveform by more than a predetermined current deviation, controlling a second half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery to reduce the current deviation;
• monitoring an AC voltage at the voltage-controlled AC output;
• comparing the monitored voltage to a desired voltage waveform;
• if the monitored voltage deviates from an instantaneous value of the desired voltage waveform by more than a predetermined voltage deviation, controlling a third half-H-bridge of semiconductor switches connected in series between positive and negative terminals of the battery to reduce the voltage deviation.