Dual‐Inverter Circuit Topologies for Supplying Open‐Ended Loads

Power electronic converters are nowadays the most suitable solution to provide a variable voltage/current in industry. The most commonly used power converter is the three-phase two-level voltage source inverter which transforms a direct-current input voltage into alternating-current output voltage with adjustable magnitude and frequency. Power inverters are used to supply three-phase loads which are typically connected in wye or delta configurations. However, in previous years, a type of connection consisting on leaving both terminal ends of the load opened has been studied as an alternative to standard wye or delta connection. To supply loads with this type of connection, two power inverters (one at each terminal end of the load) are required in a circuit topology called dual-inverter. In this chapter, a general study of the dual-inverter topology is presented. The advantages and issues of such converter are studied and different modulation strategies are shown and discussed. Moreover, multilevel dual-inverter converters are presented as an extension to the basic two-level idea. For evaluation purposes, simulations results are presented

Modulation strategies for an open-end winding induction machine fed by a two-output indirect matrix converter

This paper presents a two-output indirect matrix converter feeding an open-ended winding induction machine. The modulation strategy for the converter input stage, which provides the DC voltage for the output stages, exploits the capability of the input rectifier to produce different DC voltage levels. Moreover, this paper includes a space vector modulation strategy for the converter output stages intended to eliminate the zero sequence load voltage. Furthermore, in order to decrease commutation losses, output stage commutation will take place at reduced voltage when load voltage requirements are low. Modulation strategies and overall system operation are verified via simulation in a PSim/Matlab platform with the machine operating under an open loop V/f control strategy. Experimental results are also presented to validate the control strategies

An Active/Reactive Power Control Strategy for Renewable Generation Systems

The development of distributed generation, mainly based on renewable energies, requires the design of control strategies to allow the regulation of electrical variables, such as power, voltage (V), and frequency (f), and the coordination of multiple generation units in microgrids or islanded systems. This paper presents a strategy to control the active and reactive power flow in the Point of Common Connection (PCC) of a renewable generation system operating in islanded mode. Voltage Source Converters (VSCs) are connected between individual generation units and the PCC to control the voltage and frequency. The voltage and frequency reference values are obtained from the P–V and Q–f droop characteristics curves, where P and Q are the active and reactive power supplied to the load, respectively. Proportional–Integral (PI) controllers process the voltage and frequency errors and set the reference currents (in the dq frame) to be imposed by each VSC. Simulation results considering high-power solar and wind generation systems are presented to validate the proposed control strategy

VCN-01 disrupts pancreatic cancer stroma and exerts antitumor effects

Background Pancreatic ductal adenocarcinoma (PDAC) is characterized by dense desmoplastic stroma that limits the delivery of anticancer agents. VCN-01 is an oncolytic adenovirus designed to replicate in cancer cells with a dysfunctional RB1 pathway and express hyaluronidase. Here, we evaluated the mechanism of action of VCN-01 in preclinical models and in patients with pancreatic cancer. Methods VCN-01 replication and antitumor efficacy were evaluated alone and in combination with standard chemotherapy in immunodeficient and immunocompetent preclinical models using intravenous or intratumoral administration. Hyaluronidase activity was evaluated by histochemical staining and by measuring drug delivery into tumors. In a proof-of-concept clinical trial, VCN-01 was administered intratumorally to patients with PDAC at doses up to 1x10(11) viral particles in combination with chemotherapy. Hyaluronidase expression was measured in serum by an ELISA and its activity within tumors by endoscopic ultrasound elastography. Results VCN-01 replicated in PDAC models and exerted antitumor effects which were improved when combined with chemotherapy. Hyaluronidase expression by VCN-01 degraded tumor stroma and facilitated delivery of a variety of therapeutic agents such as chemotherapy and therapeutic antibodies. Clinically, treatment was generally well-tolerated and resulted in disease stabilization of injected lesions. VCN-01 was detected in blood as secondary peaks and in post-treatment tumor biopsies, indicating virus replication. Patients had increasing levels of hyaluronidase in sera over time and decreased tumor stiffness, suggesting stromal disruption. Conclusions VCN-01 is an oncolytic adenovirus with direct antitumor effects and stromal disruption capabilities, representing a new therapeutic agent for cancers with dense stroma