According to an aspect of the present disclosure, an uninterruptible power supply (UPS) system is provided. The UPS system includes a first input configured to be coupled to an input power source, a second input configured to be coupled to an energy storage device, an output configured to provide output power, a power conversion circuit (PCC) configured to convert power received from at least one of the input power source or the energy storage device, an output circuit coupled to the PCC and the output, and a controller. The PCC includes a first inductor and a second inductor magnetically coupled to the first inductor. The controller is configured to control the PCC to provide, via the first inductor, DC power derived from the input power source to the output circuit, and provide, via the first and second inductors, DC power derived from the energy storage device to the output circuit.

In the present uninterruptible power supply apparatus (U1), in a power failure of a commercial AC power supply (41), a switch (1) is turned off to electrically cut off the commercial AC power supply (41) from an AC input filter (2), and when DC voltage (E=EpEn) that is the difference between terminal-to-terminal voltages (Ep, En) of first and second capacitors (C1, C2) exceeds a threshold voltage (ETH), first and second IGBT devices (Q1, Q2) or third and fourth IGBT devices (Q3, Q4) included in the converter (3) are turned on and off to reduce DC voltage (E).

A method for selecting a power source for a load is provided. The method includes monitoring the primary power source, when the primary power source is providing power to the load, determining if a condition of the primary power source crosses a first threshold, when the condition crosses the first threshold, turning on a first power field effect transistor to couple a back-up power source to the load through a second power field effect transistor, when the primary power source is not providing power to the load, determining if a condition of the primary power source crosses a second threshold, and when the condition crosses the second threshold, switching off the first power field effect transistor to couple the primary power source to the load through a third power field effect transistor.

A control system and methods for a multilevel power converter are provided. The converter includes a rectifier coupled to a DC link having a midpoint coupled to electrical ground that divides the DC link into two halves. The control system is configured to generate a reference current command for controlling an output of the rectifier, the reference current command generated based on a difference between a desired and measured DC link voltage value. The system is also configured to determine a zero-sequence current component of input current supplied to the multilevel power converter, wherein the zero-sequence current component is associated with non-linearities in said multilevel power converter that cause ground current injection into the input current by the rectifier. The system is further configured to subtract the determined zero-sequence current component from the reference current command to reduce the ground current injected into the input current by the rectifier.

Technologies for interactive predictive control of uninterruptible power supply systems are disclosed. In an illustrative embodiment, a method of controlling a double-conversion uninterruptible power supply (UPS) system may include defining, with a digital signal processor (DSP), a curve as a function of a plurality of user-input reference points associated with an inductor coupled to either an input or an output of the double-conversion UPS system, where the curve is indicative of an electromagnetic behavior of the inductor. The method may also include determining, with the DSP, in response to an application of current to the inductor, an inductance value for the inductor based on the defined curve and the applied current. The method may further include setting, with the DSP, as a function of the determined inductance value, a duty cycle to control switching of at least one of an active rectifier and an inverter of the double-conversion UPS system.

Technologies for interactive predictive control of uninterruptible power supply systems are disclosed. In an illustrative embodiment, a method of controlling a double-conversion uninterruptible power supply (UPS) system may include defining, with a digital signal processor (DSP), a curve as a function of a plurality of user-input reference points associated with an inductor coupled to either an input or an output of the double-conversion UPS system, where the curve is indicative of an electromagnetic behavior of the inductor. The method may also include determining, with the DSP, in response to an application of current to the inductor, an inductance value for the inductor based on the defined curve and the applied current. The method may further include setting, with the DSP, as a function of the determined inductance value, a duty cycle to control switching of at least one of an active rectifier and an inverter of the double-conversion UPS system.

According to one aspect, embodiments of the invention provide a UPS comprising a plurality of inputs, a PFC converter configured to convert 3-phase input power into DC power, an inverter coupled to a positive DC bus and a negative DC bus and configured to convert the DC power received from the positive DC bus and the negative DC bus into output AC power, a first output configured to provide a first portion of the output AC power from the inverter to a load, a second output configured to provide a second portion of the output AC power from the inverter to the load, a third output configured to be selectively coupled to a neutral line via the inverter, and a controller configured to operate the inverter to generate current between the load and the neutral line via the third output and the inverter.

A power system including a rectifier and an inverter. The rectifier has a plurality of phase input terminals and a plurality of rectifier output terminals that provide respective rectified outputs, rectifier circuitry that rectifies the signals on the phase input terminals to generate respective rectified outputs on the rectifier output terminals, a rectifier neutral to receive a power source neutral, and capacitors connected between the rectifier neutral and the rectifier output terminals. The inverter includes a respective plurality of inverter input terminals respectively connected to the rectifier output terminals, a plurality of inverter output terminals, and an inverter neutral. The rectifier neutral and the inverter neutral are coupled by a conductor to form a same neutral.

The present disclosure provides to a power converter including an AC input terminal (ACin), a neutral terminal (N), an AC output terminal (ACout), an AC/DC converter circuit (210) connected between the AC input terminal, a positive DC terminal (DCP), and a negative DC terminal (DCN), a DC capacitor (C15) connected between the positive DC terminal (DCP) and the negative DC terminal (DCN), a line frequency commutated neutral circuit (220) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), and the neutral terminal (N), and a DC/AC converter circuit (230) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), the AC output terminal (ACout), and the neutral terminal (N). The power converter further includes an auxiliary converter circuit (240) connected between the positive DC terminal (DCP), the negative DC terminal (DCN), and the neutral terminal (N).

A power converter with a common DC power source includes a DC power source and at least two power modules. Each of the power modules is coupled with each other and coupled to the DC power source. Each of the power module includes a coupled inductive component coupled to the DC power source, a DC output conversion unit coupled to the coupled inductive component, and a capacitor group having a coupling point. By using the coupled inductive component, it is to solve the problem of return current between the power modules caused by coupling multiple coupling points to each other.