Reducing switching losses in series connected bridge inverters and amplifiers

A staggered-voltage multiple-phase circuit comprising:

• a first-phase portion for generating a voltage signal in a first phase, and a second-phase portion for generating the voltage signal in a second phase out of phase with the first phase, each of the first-phase and second-phase portions comprising:
• a first circuit configured to generate a first output corresponding to a plurality of segments of the voltage signal minus a corresponding plurality of constant values;
• and
• a second circuit comprising a full-bridge switch circuit connected in series with the first circuit and configured to receive a DC voltage and to generate a second output corresponding to at least some of the plurality of constant values, such that the sum of the first output and the second output corresponds to at least a portion of the voltage signal;
• control circuitry arranged to control the first and second circuits in the first-phase and second-phase portions so as to cause the first and second circuits to generate the first and second outputs respectively;
• and
• independent and isolated power supplies connected to each first and second circuit in each of the first-phase and second-phase portions to supply DC voltage to the first and second circuits of the first-phase and second-phase portions.

A staggered-voltage multiple-phase circuit comprising:

• a first-phase portion for generating a voltage signal in a first phase, and a second-phase portion for generating the voltage signal in a second phase out of phase with the first phase, each of the first-phase and second-phase portions comprising:
• a first circuit configured to generate a first output corresponding to a plurality of segments of the voltage signal minus a corresponding plurality of constant values;
• and
• a second circuit comprising a full-bridge switch circuit connected in series with the first circuit and configured to receive a DC voltage and to generate a second output corresponding to at least some of the plurality of constant values, such that the sum of the first output and the second output corresponds to at least a portion of the voltage signal;
• control circuitry arranged to control the first and second circuits in the first-phase and second-phase portions so as to cause the first and second circuits to generate the first and second outputs respectively;
• and
• an output transformer having first and second independent and isolated primary coils connected to respective outputs of the first-phase and second-phase portions to receive the voltage signal in the first phase generated by the first-phase portion and to receive the voltage signal in the second phase generated by the second-phase portion.

A staggered-frequency multiple-phase circuit comprising:

• a first-phase portion for generating a voltage signal in a first phase, and a second-phase portion for generating the voltage signal in a second phase out of phase with the first phase, each of the first-phase and second-phase portions comprising:
• a first pulse width modulated bridge circuit configured to receive a DC voltage and to operate at a first pulse width modulated switch frequency to generate a first output corresponding to an AC signal in a first region of the AC signal;
• at least a second pulse width modulated bridge circuit connected in series with the first pulse width modulated bridge circuit and configured to receive a DC voltage and to operate at a second pulse width modulated switch frequency substantially lower than the first pulse width modulated switch frequency to generate a second output corresponding to the AC signal in a second region of the AC signal in which the AC signal changes less rapidly than in the first region, minus a maximum voltage magnitude of the first region;
• and
• pulse width modulation circuitry arranged to modulate the first pulse width modulated bridge circuit in the first-phase and second-phase portions at the first pulse width modulated frequency to generate the first output when the AC signal is in the first region and to modulate the second pulse width modulated bridge circuit in the first-phase and second-phase portions at the second pulse width modulated frequency to generate the second output when the AC signal is in the second region different from the first region;
• and
• independent and isolated power supplies connected to each first and second pulse width modulated bridge circuit in each of the first-phase and second-phase portions to supply DC voltage to the first and second pulse width modulated bridge circuits of the first-phase and second-phase portions.

A staggered-frequency multiple-phase circuit comprising:

• a first-phase portion for generating a voltage signal in a first phase, and a second-phase portion for generating the voltage signal in a second phase out of phase with the first phase, each of the first-phase and second-phase portions comprising:
• a first pulse width modulated bridge circuit configured to receive a DC voltage and to operate at a first pulse width modulated switch frequency to generate a first output corresponding to an AC signal in a first region of the AC signal;
• at least a second pulse width modulated bridge circuit connected in series with the first pulse width modulated bridge circuit and configured to receive a DC voltage and to operate at a second pulse width modulated switch frequency substantially lower than the first pulse width modulated switch frequency to generate a second output corresponding to the AC signal in a second region of the AC signal in which the AC signal changes less rapidly than in the first region, minus a maximum voltage magnitude of the first region;
• and
• pulse width modulation circuitry arranged to modulate the first pulse width modulated bridge circuit in the first-phase and second-phase portions at the first pulse width modulated frequency to generate the first output when the AC signal is in the first region and to modulate the second pulse width modulated bridge circuit in the first-phase and second-phase portions at the second pulse width modulated frequency to generate the second output when the AC signal is in the second region different from the first region;
• and
• an output transformer having first and second independent and isolated primary coils connected to respective outputs of the first-phase and second-phase portions to receive the voltage signal in the first phase generated by the first-phase portion and to receive the voltage signal in the second phase generated by the second-phase portion.