Google Inc.

Monolithic Power Systems, Inc.

Sangsun Kim

Honggang Sheng

Ken Krieger

Anand Ramesh

Cornelius Bendict O'Sullivan

Wei P Chen

Pascal C Kam

William Leslie Dailey

Craig Kaneshiro

Scott Aldous

John Zipfel

Krishnanjan Gubba Ravikumar

Shane Roland Nay

Eduardo Marcelo Lipiansky

Francisco Javier Elias

Jimmy Clidaras

Jyoti Sastry

Arunava Majumdar

Ronald Scott Collyer

Mark Ramon Imbertson

Murti Salapaka

Subhrajit Roychowdhury

Srinivasa Murthy Salapaka

Di Xu

Neilus O'Sullivan

Anthony Tonizzo

Jianshui Wang

Ho Kong Mah

A system and method for power pooling, the system including a shared power line, a plurality of backup power supplies connected to the shared power line through respective transformers and one or more controllers configured to, for each respective backup power supply, after passage of a different respective predetermined amount of time, determine whether a transformer connected to the backup power supply is energized. In response to the transformer being energized, the controllers synchronize the backup power supply with the transformer and then set a switch positioned between the backup power supply and the transformer to a fully closed state. In response to the transformer not being energized, the controllers transition the switch from a fully open state to the fully closed state according to an inrush current limiting scheme.

System and method for transitioning to backup power pooling

Disclosed are devices, systems, and methods for operating a backup power source or an uninterruptible power supply (UPS) that can be used in data centers and that provide a backup power source to power the data center when utility power is compromised. A power delivery system that provides power to a primary system may include a UPS with a state timing control system that operates a bypass static switch. The state timing control system can determine when to transition the primary system from the utility power supply to the backup UPS, based on the current AC voltage conditions. The state timing control system may perform modeling to emulate the intermediate DC voltage of an actual rectifier, and particularly emulate the holdup capacitor voltage. The emulated capacitor voltage can be obtained in real time by both an input power model based on RMS utility voltage and the actual rectifier output load.

Timing determination for UPS power transfer

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.

Transformerless power conversion

A server rack with vertically stacked shelves is disclosed. The shelves are used for housing loads (e.g. servers) and power supply units. Thus, both the power supply units and the servers are vertically stacked in the rack. An array of vertical and horizontal busses is secured to the back side of the server rack to electrically couple the servers with the power supply units. The arrangement of the PSUs and the busses provides for uniform current density across the server rack. The devices placed on the shelves are accessible and serviceable from the front of the server rack. The server rack can be placed within or secured to a device, system or a server room in a vertical orientation, a horizontal orientation or at an angle.

Server rack architecture that facilitates reduced current density

A method for converting alternating current (AC) power to direct current (DC) power in a non-isolated power converter includes receiving a three-phase power supply, transforming the three phase power supply into six voltage phases, half-wave rectifying the AC current, applying a power factor correction to achieve DC power, and outputting a DC power signal. The three-phase power supply has an AC current. The six voltage phase is transformed at a secondary side of a three-phase distribution transformer, which includes a center tap located at the secondary side of the three-phase distribution transformer and one or more AC wire conductors. The AC wire conductors carry the transformed power supply. The half-wave rectification occurs at the secondary side of the three-phase distribution transformer. An arrangement of rectifier diodes on the AC wire conductors accomplishes the half-wave rectification. The output DC power signal has an output voltage at a DC output.

Converting alternating current power to direct current power

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for non-isolated power conversion. In one aspect, a method includes generating first and second rectified outputs using a rectifier with a first input and a second input connected respectively to a first and second output of a power source, capacitively coupling the first and second rectified outputs to a neutral, generating first and second AC outputs from the first and second rectified outputs, and capacitively coupling the first and second AC outputs to the neutral. Other embodiments of this aspect include corresponding systems, apparatus, and computer programs, configured to perform the actions of the methods, encoded on computer storage devices.

In general, one innovative aspect of the subject matter described in this specification can be embodied in a load control system configured to perform load control operations comprising: measuring a voltage on an electrical grid at a plurality of times; determining, for each time of the plurality of times, a difference between a specified normal voltage and the respective measured voltage at that time; summing the differences between the specified normal voltage and the measured voltages to determine a curtailment level; determining whether the curtailment level exceeds a first threshold curtailment level; and in response to determining that the curtailment level exceeds the first threshold curtailment level, adjusting an amount of power drawn by a load.

Load curtailment on an electrical grid

Aspects of the disclosure relate generally to uninterruptible power supply units for systems requiring back up power. Each unit may include UPS circuitry for controlling charging and allowing discharging of a battery. The UPS circuitry may includes a controller and a plurality of metal-oxide semiconductor field effect transistors ('MOSFET') switches. The MOSFETs may include charging and discharging MOSFETs arranged in series with the battery all driven by a single gate driver, such as a controller. In this regard, the controller may limit the charging current though all of the MOSFETs and charge the battery. The MOSFETs may be arranged such that if the charging MOSFET fails, the redundant charging MOSFET may continue to limit the charging current to the battery. Similarly, a redundant discharging MOSFET may be arranged in series with a discharging MOSFET in order to continue to provide discharging current if the discharging MOSFET fails.

Redundant charging and discharging MOSFET driving in battery backup system

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for controlling a battery power source. In one aspect, a system includes a first MOSFET having a first gate, a first source, and a first drain. A second MOSFET having a second gate, a second source, and a second drain. The first source is connected to the second source, and the second drain is coupled to a ground. A control circuit connected to the first gate and the second gate and that provides control signals to the first gate and the second gate that cause the first and second MOSFETS to operate in saturation regions during a first operational state to cause the first power source to discharge and the first MOSFET operates in a linear region during a second operational state to limit a charging current that charges the first power source.

Redundant residential power sources

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for shaping grid currents output from parallel inverters in a power distribution system with virtual impedances. In one aspect, a method includes receiving a measurement of the current output from the inverter, processing the measurement of the current to extract a first current component having a particular frequency, obtaining a second current component based on the measurement of the current and the extracted first current component, weighing the first and second current components with respective first and second impedances to obtain respective first and second component voltages, the first impedance having a lower impedance amplitude than the second impedance, obtaining a shaped voltage based on the first and second component voltages, and outputting a control signal to the inverter, the control signal causing the inverter to output the shaped voltage to the power distribution bus.

Virtual impedance shaping

Devices and methods for monitoring and determining alternating current (AC) power system parameters are provided. In some implementations, the device can include a processor; and at least one non-transitory computer-readable medium storing computer-executable instructions for implementing a number of components. The components include a monitor configured to: sense an AC line voltage signal and an AC current voltage signal; filter the AC line voltage signal; calculate average AC line voltage and current values based, at least, on a DC voltage and current values corresponding to the AC line voltage and current signals, respectively; determine fundamental AC line voltage and current signals based, at least, on zero crossings of the respective average AC line voltage value and the average AC line current value; and determine one or more AC power system parameters based, at least, on the fundamental AC line voltage signal and the fundamental AC line current signal.

AC power monitoring and parameter determination

Methods and systems supply uninterrupted power to a load using a backup battery module. A driver circuit connects the load and the backup battery module such that the operational range of the load voltage is narrower than the operational range of the battery voltage. Different charging and discharging paths of the driver circuit may be used to limit the DC bus voltage to values lower than the battery voltage. The proposed systems and methods can increase power efficiency and decrease the cost of power supply and conversion operations.

Growing community of inventors

San Jose, CA, United States of America

Sangsun Kim