Current sharing among bidirectional double-base bipolar junction transistors. One example is a method comprising: conducting current through a first bidirectional double-base bipolar junction transistor (first B-TRAN); conducting current through a second B-TRAN the second B-TRAN coupled in parallel with the first B-TRAN; measuring a value indicative of conduction of the first B-TRAN, and measuring a value indicative of conduction of the second B-TRAN; and adjusting a current flow through the first B-TRAN, the adjusting responsive to the value indicative of conduction of the first B-TRAN being different than the value indicative of conduction of the second B-TRAN.

A photonic AC-DC voltage and current equivalence converter includes: a photonic chip; a weak thermal link; an isothermal region; a resistive electrode; an isothermal region photonic nanoresonator; an isothermal region waveguide; a chip photonic nanoresonator; and a chip waveguide, such that an ac voltage is determined from matching a temperature rise of the isothermal region due to a primary elevated temperature of the isothermal region when ac voltage is received by the resistive electrode.

A photonic AC-DC voltage and current equivalence converter includes: a photonic chip; a weak thermal link; an isothermal region; a resistive electrode; an isothermal region photonic nanoresonator; an isothermal region waveguide; a chip photonic nanoresonator; and a chip waveguide, such that an ac voltage is determined from matching a temperature rise of the isothermal region due to a primary elevated temperature of the isothermal region when ac voltage is received by the resistive electrode.

A piezoelectric actuator control device comprising a first voltage converter supplying a DC voltage on a DC power supply bus to which is connected a second voltage converter capable of generating a variable excitation voltage under the control of a control computer, the second voltage converter comprising two switch half-bridges mounted in parallel with the terminals of a bus capacitor, the control computer being suitable for controlling the two switch half-bridges according to a first control configuration, in which they are controlled independently in order to each supply a voltage in a range between zero and a maximum positive value and according to a second control configuration, in which they are jointly controlled as a full-bridge for supplying a voltage between a minimum negative value and said maximum positive value.

A piezoelectric actuator control device comprising a first voltage converter supplying a DC voltage on a DC power supply bus to which is connected a second voltage converter capable of generating a variable excitation voltage under the control of a control computer, the second voltage converter comprising two switch half-bridges mounted in parallel with the terminals of a bus capacitor, the control computer being suitable for controlling the two switch half-bridges according to a first control configuration, in which they are controlled independently in order to each supply a voltage in a range between zero and a maximum positive value and according to a second control configuration, in which they are jointly controlled as a full-bridge for supplying a voltage between a minimum negative value and said maximum positive value.

A driving system includes a first alternating-current rotary electrical machine and a second alternating-current rotary electrical machine. The driving system includes: a first inverter electrically connected to the first alternating-current rotary electrical machine; a second inverter electrically connected to a first end of each of phase windings constituting the second alternating-current rotary electrical machine; a step-up converter; and a third inverter that is electrically connected to a second end of each of the phase windings and transfers power to a second direct-current power source different from the first direct-current power source to drive the second alternating-current rotary electrical machine. The step-up converter raises an output voltage of the first direct-current power source and outputs the output voltage to the first inverter and the second inverter. The second direct-current power source and the first alternating-current rotary electrical machine are connected by a single connection route.

A driving system includes a first alternating-current rotary electrical machine and a second alternating-current rotary electrical machine. The driving system includes: a first inverter electrically connected to the first alternating-current rotary electrical machine; a second inverter electrically connected to a first end of each of phase windings constituting the second alternating-current rotary electrical machine; a step-up converter; and a third inverter that is electrically connected to a second end of each of the phase windings and transfers power to a second direct-current power source different from the first direct-current power source to drive the second alternating-current rotary electrical machine. The step-up converter raises an output voltage of the first direct-current power source and outputs the output voltage to the first inverter and the second inverter. The second direct-current power source and the first alternating-current rotary electrical machine are connected by a single connection route.

Some embodiments of the invention include a pre-pulse switching system. The pre-pulsing switching system may include: a power source configured to provide a voltage greater than 100 V; a pre-pulse switch coupled with the power source and configured to provide a pre-pulse having a pulse width of T.sub.pp; and a main switch coupled with the power source and configured to provide a main pulse such that an output pulse comprises a single pulse with negligible ringing. The pre-pulse may be provided to a load by closing the pre-pulse switch while the main switch is open. The main pulse may be provided to the load by closing the main switch after a delay T.sub.delay after the pre-pulse switch has been opened.

Some embodiments of the invention include a pre-pulse switching system. The pre-pulsing switching system may include: a power source configured to provide a voltage greater than 100 V; a pre-pulse switch coupled with the power source and configured to provide a pre-pulse having a pulse width of T.sub.pp; and a main switch coupled with the power source and configured to provide a main pulse such that an output pulse comprises a single pulse with negligible ringing. The pre-pulse may be provided to a load by closing the pre-pulse switch while the main switch is open. The main pulse may be provided to the load by closing the main switch after a delay T.sub.delay after the pre-pulse switch has been opened.

An ignition device for welding equipment includes a capacitor, a transformer, a high voltage output circuit connected to a secondary winding of the transformer, a discharging switch enabling discharge of the capacitor to a primary winding of the transformer, a charger and an operation control circuit that controls the charger and the discharging switch.