A voltage command estimator is configured to estimate a minimum required variable DC bus voltage based on the first direct-axis current/voltage command, the first quadrature-axis current/voltage command, the second direct-axis current/voltage command, and the second quadrature-axis current/voltage command for a respective time interval. The voltage command estimator is configured to provide the estimated minimum required variable DC bus voltage to a voltage regulator to adjust the observed voltage level of the variable DC voltage bus to the estimated minimum required variable DC bus voltage to maintain the operation, as commanded by the voltage/current commands, of the first electric machine under the first variable load and the second electric machine under the second variable load at the time interval.

A partial-resonant converter is provided herein and comprises a partial resonant link formed by a magnetizing link inductor connected in parallel with a first capacitor on a primary winding side of a transformer and a second capacitor on a secondary winding side of the transformer, a pair of series connected switches coupled across the magnetizing link inductor and the first capacitor, and a plurality of forward conducting bidirectional blocking switches that connect an input source and an output load to the magnetizing link inductor during operation.

A drive system includes a first converter and at least one second converter. The first converter has, inside its housing, a first rectifier whose DC-voltage-side terminal is connected, e.g., directly connected, to the DC-voltage-side terminal of a first inverter of the first converter. A first capacitance is connected in parallel with the DC-voltage-side terminal of the first inverter. The second converter, or each second converter, has, inside its housing, a second rectifier whose DC-voltage-side terminal is connected via inductivities, i.e., for example, restrictors, to the DC-voltage-side terminal of a second inverter of the second converter. A second capacitance is connected in parallel with the DC-voltage-side terminal of the second inverter, and the DC-voltage-side terminal of the first inverter is connected via first inductivities to the DC-voltage-side terminal of the second inverter.

Reduced-power dynamic data circuits with wide-band energy recovery are described herein. In one embodiment, a circuit system comprises at least one sub-circuit in which at least one of the sub-circuits includes a capacitive output node that is driven between low and high states in a random manner for a time period and an inductive circuit path coupled to the capacitive output node. The inductive circuit path includes a transistor switch and an inductor connected in series to discharge and recharge the output node to a bias supply. A pulse generator circuit generates a pulse width that corresponds to a timing for driving the output node.

A multi-winding single-stage multi-input boost type high-frequency link's inverter with simultaneous/time-sharing power supplies, having the circuit structure formed by connecting a plurality of mutually isolated high-frequency inverter circuits having an input filter and an energy storage inductor, a common output cycloconverter and filter circuit by a multi-input single-output high-frequency transformer. Each input end of the multi-input single-output high-frequency transformer is connected in one-to-one correspondence to the output end of each high-frequency inverter circuit. The output end of the multi-input single-output high-frequency transformer is connected to the input end of the output cycloconverter and filter circuit. The inverter has the following characteristics: multiple input sources are connected to a common ground or a non-common ground. The multiple input sources supply power to load in a simultaneous/time-sharing manner. The output and input high-frequency isolation is performed. The output cycloconverter and filter circuit is shared.

A converter is configured for connecting between a solar cell and an inverter configured to convert direct-current power output from the solar cell into alternating current power, and the converter is configured to increase the potential-to-ground at the negative terminal of the solar cell to greater than the potential-to-ground at the negative terminal of the inverter when outputting the direct-current power generated by the solar cell to the inverter side.

A resonant converter and a manufacturing method of a transformer thereof are provided. The resonant converter includes a full bridge circuit, an element, a first branch circuit, a second branch circuit and a secondary winding. The full bridge circuit includes a first node and a second node. The element includes an inductor or a capacitor. The first branch circuit includes a first primary winding. The second branch circuit includes a second primary winding, and the first and second primary windings have the same turn number. The transformer is constructed by the first and second primary windings and the secondary winding. The first branch circuit, the element and the second branch circuit are sequentially coupled in series between the first and second nodes. The first branch circuit and the second branch circuit are symmetrically located with respect to the element. The first and second branch circuits have the same impedance.

A resonant inverter apparatus supplies a high AC voltage to a discharge load. In this apparatus, an inverter circuit converts a DC voltage to an AC voltage using a plurality of switching elements. A transformer steps up the AC voltage and generates a high AC voltage. A DC voltage detecting unit detects a value of a DC voltage supplied to the inverter circuit. A control unit generates a driving pulse for performing on/off switching of the switching elements. The switching elements include first and second switching elements. The control unit performs phase angle control of the driving pulse. In response to the detected value of the DC voltage being greater than a reference value, the control unit sets a switching phase angle of the second switching element relative to the first switching element serving as reference, based on the magnitude of the valued of the DC voltage.

A threshold detection system can be configured to monitor a location (e.g., a DC link) for overcurrent. The threshold detection system can be configured to generate a pulse width modulated signal with a duty cycle that is proportional to current through the DC link. The threshold detection system can be configured to determine whether the duty cycle exceeds a selected threshold.

A circuit structure of a voltage type single-stage multi-input low-frequency link inverter with an external parallel-timesharing select switch is formed by connecting a plurality of input filters connected to ground and a common output low-frequency isolation voltage-transformation filter circuit through a multi-input single-output high-frequency inverter circuit. Each input end of the multi-input single-output high-frequency inverter circuit is connected to an output end of each of the input filters in a manner of one-to-one correspondence. An output end of the multi-output single-input high-frequency inverter circuit and the output low-frequency isolation voltage-transformation filter circuit are connected. The multi-input single-output high-frequency inverter circuit includes an external multi-path parallel-timesharing select four-quadrant power switch circuit and a bidirectional power flow single-input single-output high-frequency inverter circuit successively connected in cascade.