In a power converter apparatus including a PFC circuit operating in a current-critical mode, a zero point of an inductor current is accurately detected. The control circuit includes a current detector unit including a first detection circuit that detects an inductor current, amplifies a voltage corresponding to the detected current with a gain, and outputs it as a detection voltage and a comparison circuit that compares the detected voltage with a predetermined reference voltage and outputs a comparison result signal. The control circuit calculates the reference voltage for making a delay when detecting the zero value of the inductor current substantially zero, based on the detected input voltage, the detected output voltage, the preset delay time, the inductance value of the inductor, the conversion factor in current/voltage converting, the power supply voltage, and the gain, and then, outputs it to the comparison circuit.

A bidirectional AC power converter, having a front-end comprising parallel sets of three switches in series, which connects multi-phase AC to coupling transformer through a first set of tank circuits, for synchronously bidirectionally converting electrical power between the multi-phase AC and a DC potential, and for converting electrical power between the DC potential to a bipolar electrical signal at a switching frequency, controlled such that two of each parallel set of three switches in series are soft-switched and the other switch is semi-soft switched; the coupling transformer being configured to pass the bipolar electrical power at the switching frequency through a second set of the tank circuits to a synchronous converter, which in turn transfers the electrical power to a secondary system at a frequency different from the switching frequency.

A neutral-point voltage balance control method and system for a three-level converter in a full power factor range. The method includes: using a large, medium, and zero vector modulation method to synthesize a reference voltage vector, and duty cycles of a large vector, a medium vector, and a zero vector; obtaining a voltage difference between two dc-link capacitors of signal acquisition, and the voltage difference as a neutral-point potential of the three-level converter; according to a value relationship between the neutral-point potential of the three-level converter and a specified threshold, selecting a small vector and calculating a duty cycle of the small vector; and updating a duty cycle of each basic vector, and obtaining a switching sequence for controlling a power switch of a three-phase bridge arm. An amplitude of a common-mode voltage of an NPC three-level converter is equal to one sixth of a dc-link voltage.

A power converter comprises a primary stage including four switches forming a first H bridge; a control circuit capable of applying a first control signal to the first H bridge; a secondary stage including four switches forming a second H bridge; a control circuit capable of applying a second control signal to the second H bridge; and a power transmission stage coupling the primary stage to the secondary stage, wherein the control circuit of the secondary stage is electrically isolated from the control circuit of the primary stage. During a measurement period of a synchronization phase, the switches of the secondary stage are maintained in a short-circuit configuration while the switches of the primary stage are controlled in switched mode.

The instant disclosure concerns a power converter including: a primary stage (110) including at least one first cut-off switch (S.sub.11, S.sub.12, S.sub.13, S.sub.14); a control circuit (112) capable of applying a first control signal to said at least ore first switch; a secondary stage (130) including at least one second cut-off switch (S.sub.21, S.sub.22, S.sub.23, S.sub.24); a control circuit (132) capable of applying a second control signal to said at least one second switch; a power transmission stage (120) coupling the primary stage (110) to the secondary stage (130), wherein the control circuit (132) of the secondary stage is electrically isolated from the control circuit (112) of the primary stage.

A neutral-point voltage balance control method and system for a three-level converter in a full power factor range. The method includes: using a large, medium, and zero vector modulation method to synthesize a reference voltage vector, and duty cycles of a large vector, a medium vector, and a zero vector; obtaining a voltage difference between two dc-link capacitors of signal acquisition, and the voltage difference as a neutral-point potential of the three-level converter; according to a value relationship between the neutral-point potential of the three-level converter and a specified threshold, selecting a small vector and calculating a duty cycle of the small vector; and updating a duty cycle of each basic vector, and obtaining a switching sequence for controlling a power switch of a three-phase bridge arm. An amplitude of a common-mode voltage of an NPC three-level converter is equal to one sixth of a dc-link voltage.

An AC/DC power converter includes input terminals, output terminals, a power factor correction circuit coupled between the input and output terminals and including at least one power switch defining a switched current path, and a current transformer including a primary winding and a secondary winding. The primary winding is coupled in series with the switched current path. The power converter also includes a first sense switch coupled with a first end of the secondary winding, a second sense switch coupled with a second end of the secondary winding, and a control circuit. The control circuit is configured to turn on the first sense switch and turn off the second sense switch during a positive polarity of the AC voltage input, and to turn off the first sense switch and turn on the second sense switch during a negative polarity of the AC voltage input.

Embodiments described herein provide a modular storage for power tool devices including a charging compartment for power tool battery packs. The modular storage includes a housing, a storage compartment in the housing, and a charger compartment in the housing including a battery pack interface configured to receive a power tool battery pack. The modular storage also includes an AC input receiving universal AC power and an active power factor correction (PFC) converter receiving AC power from the AC input and configured to convert the AC power to a high-voltage DC output. The modular storage further includes a DC-DC converter electrically connected between the active PFC converter and the battery pack interface, the DC-DC converter including an active clamp flyback converter.

A bidirectional AC power converter, having a front-end comprising parallel sets of three switches in series, which connects multi-phase AC to coupling transformer through a first set of tank circuits, for synchronously bidirectionally converting electrical power between the multi-phase AC and a DC potential, and for converting electrical power between the DC potential to a bipolar electrical signal at a switching frequency, controlled such that two of each parallel set of three switches in series are soft-switched and the other switch is semi-soft switched; the coupling transformer being configured to pass the bipolar electrical power at the switching frequency through a second set of the tank circuits to a synchronous converter, which in turn transfers the electrical power to a secondary system at a frequency different from the switching frequency.

A bidirectional power factor correction (PFC) module is coupled to an AC power source, an energy storage unit, and a DC bus. The bidirectional PFC module includes a bridge arm assembly and a control unit. The bridge arm assembly includes a first bridge arm, a first inductor, a second inductor, and a second bridge arm. The control unit provides a plurality of control signals to control the first bridge arm and the second bridge arm to make the bidirectional PFC module operate in an AC power supply mode, a DC power supply mode, or a power feed mode.