2872 results about "Fixed frequency" patented technology

An automated meter reading network system to collect utility usage data from multiple utility meters having utility meter sensors is provided. The system includes multiple meter data collectors each in communication with one or more utility meters to collect utility usage data and forming a wireless mesh communications network characterized by having a varying frequency mode of operation. The system also includes a host computer in communication with the meter data collectors either directly or through multiple field host data collectors, which can be connected to the host computer through a wide area network. The system also includes a meter data collector program product at least partially stored in the memory of the host computer adapted to manage the mesh communication network that is adapted to vary the frequency mode of at least portions of the mesh communication network between a fixed frequency mode and a frequency hopping spread spectrum mode to enhance network performance.

A controlling system and method for controlling an electrochromic element, utilizes a simplified architecture, including at least a microcontroller, a A / D converter and a charging circuit, to reduce complexity of the whole system for reaching both of a respond time and cost savings for the electrochromic element. And the controlling system and method only utilizes a fixed frequency to drive the electrochromic element for reaching a better reliability than a variable duty cycle driver used in prior art.

The present invention provides_a power converter that can be used to interface a generator (4) that provides variable voltage at variable frequency to a supply network operating at nominally fixed voltage and nominally fixed frequency and including features that allow the power converter to remain connected to the supply network and retain control during supply network fault and transient conditions. The power converter includes a generator bridge (10) electrically connected to the stator of the generator (4) and a network bridge (14). A dc link (12) is connected between the generator bridge (10) and the network bridge (14). A filter (16) having network terminals is connected between the network bridge (14) and the supply network. A first controller (18) is provided for controlling the operation of the semiconductor power switching devices of the generator bridge (14). Similarly, a second controller (46) is provided for controlling the operation of the semiconductor power switching devices of the network bridge (14). The first controller (18) uses a dc link voltage demand signal (VDC13 GEN*) indicative of a desired dc link voltage to control the semiconductor power switching devices of the network bridge (10) to achieve the desired level of dc link voltage that corresponds to the dc link voltage demand signal (VDC13 GEN*). The second controller (46) uses a power demand signal (P*) indicative of the level of power to be transferred from the dc link to the supply network through the network bridge (14), and a voltage demand signal (VTURB*) indicative of the voltage to be achieved at the network terminals of the filter (16) to control the semiconductor power switching devices of the network bridge (14) to achieve the desired levels of power and voltage that correspond to the power and voltage demand signals (P* and VTURB*).