摘要:
Disclosed are useful constructs and methods for the expression of proteins using primary translation products that are processed within a recombinant host cell. Constructs comprising a single open reading frame (sORF) are described for protein expression including expression of multiple polypeptides. A primary translation product (a pro-protein or a polyprotein) contains polypeptides such as inteins or hedgehog family auto-processing domains, or variants thereof, inserted in frame between multiple protein subunits of interest. The primary product can also contain cleavage sequences such as other proteolytic cleavage or protease recognition sites, or signal peptides which contain recognition sequences for signal peptidases, separating at least two of the multiple protein subunits. The sequences of the inserted auto-processing polypeptides or cleavage sites can be manipulated to enhance the efficiency of expression of the separate multiple protein subunits. Also disclosed are independent aspects of conducting efficient expression, secretion, and/or multimeric assembly of proteins such as immunoglobulins. Where the polyprotein contains immunoglobulin heavy and light chain segments or fragments capable of antigen recognition, in an embodiment a selectable stoichiometric ratio is at least two copies of a light chain segment per heavy chain segment, with the result that the production of properly folded and assembled functional antibody is made. Modified signal peptides, including such from immunoglobulin light chains, are described.
摘要:
A phase locked loop (PLL) circuit provides ac devices, such as power inverters and power measurement devices, with a reliable means for synchronizing to ac electrical systems. In an exemplary embodiment, the PLL circuit is configured for operation with single-phase electrical systems and offers substantial noise immunity by basing its locking operations on measured fundamental components, i.e., measured x-y phasors, of the electrical system voltage. Further, with its phasor-based locking operations and with its timer/counter-based operation, the PLL circuit can be implemented partly or wholly in digital processing logic.
摘要:
A multivariable control system provides regulation for a plurality of control variables of interest based on selecting a particular one of the variables for regulation relative to a corresponding setpoint, while continuing to monitor the other variables and switching regulation control over to another one of the variables as needed to maintain all of them within their allowed ranges. The system includes one or more PID regulators that tune themselves for the particular variables selected for regulation control. In an exemplary embodiment, the control system is configured for controlling an alternative energy system, wherein it includes one or more power flow devices that control power flow between electrical energy storage devices (EESDs) and a common dc bus and/or power flow between the dc bus and an external ac electrical system.
摘要:
A control circuit synchronizes an ac power inverter to the mains voltage of an electrical grid by matching the fundamental phasor components of the inverter's output voltage to the fundamental phasor components of the mains voltage. Once such matching meets an acceptable voltage error threshold, the control circuit initiates contactor closure, verifies contactor closure, and then initiates a changeover from voltage-mode control used in synchronization operations to a current-mode control of the inverter's output. The control circuit provides corresponding disconnection control when disconnection from the grid is desired, wherein the regulated power of the inverter is ramped down in controlled fashion until it reaches a lower threshold whereupon contactor opening is initiated. Once contactor opening is verified, regulation control reverts to stand-alone voltage mode control or to shut down, as needed or desired.
摘要:
A power inverter includes a regulator circuit that controls real and reactive power output by the inverter. The regulator measures real and reactive output power by calculating x-phasor components of the inverter's voltage and current output waveforms. Phasor calculation can be adapted for one or more pairs of single-phase voltages and currents. Determining the fundamental in-phase and quadrature components of output voltage and current reduces computational complexity by permitting the regulator to perform its power control processing largely in a dc signal domain, and enables separate real and reactive power control. The power inverter can include islanding detection logic, which exploits the ability to separately control reactive power. Exemplary islanding detection logic is based on determining whether changing the amount of reactive power output by the inverter induces an output frequency shift.