Engineering Fundamentals Of Multi-MW Variable Frequency Drives - How They Work, Basic Types, And Application Considerations.

Tutorialpg. 177-194A brief historical overview of the conversion from mechanical systems to electrical systems at low power levels is presented to gain an understanding of what is occurring at multiple megawatt (MW) power levels in industry. An overview of drive technologies as they apply to multiple MW power levels is presented to assist an application engineer in applying an electrical system. The benefits of applying a variable frequency drive (VFD) system, such as greater reliability, smaller size, lower production costs, better performance, and increased automation potential are available with existing technology. A total cost of ownership (TCO) process is discussed and it defines the steps and tradeoffs required in determining an optimum system solution. The transition in the multiple MW market from mechanical systems to VFD systems is in process, and the rate of transition will accelerate over the next 10 years as the enabling drive technologies continue to be developed

A Hardware-in-the-Loop Platform for DC Protection

Real-time (RT) simulation of power and energy conversion systems allows engineers to interface both simulation- and hardware-based controls using controller hardware-in-the-loop (CHiL) simulation of networks of power electronic converters (PECs) to de-risk highly developmental systems, such as next generation electrified transportation systems and dc microgrids. CHiL exploration and performance verification moves a design from technology readiness level (TRL) 3 to TRL 4 without incurring significant cost investments in developmental hardware platforms, which otherwise discourages such endeavors. An RT CHiL simulation platform suitable for explorations of protective equipment, protection schemes, and networked PEC dc and mixed dc-ac power distribution architectures must be capable of simulating common-mode behavior, various grounding schemes, and fault transients at sufficiently high resolution. This article demonstrates this capability using a latency-based linear multistep compound (LB-LMC) simulation method implemented in a commercially sustainable, adaptable, and expandable FPGA-based test and instrumentation platform. The proposed CHiL platform achieves RT power system simulations, including detailed switching commutations of networked PECs, with 50-ns resolution, and faithfully produces resonant and transient behaviors associated with line-to-ground (LG) and line-to-line (LL) faults and fault recovery in ungrounded PEC-based dc systems. This resolution in RT cannot be achieved with today's commercial off-the-shelf CHiL platforms. This article demonstrates the need for high-resolution RT simulation of LG and LL faults within dc systems, and demonstrates a CHiL approach that enables dc protection design explorations and protective control hardware testing while taking into account the realistic aspects that affect fault characteristics in PEC-based dc systems, such as cable current rating and length, cable and PEC parasitic LG capacitance, and PEC internal respon..