Microhydro Electronic Load Controller

Context & Motivation
  • Microhydro systems (10 kW to 100 kW) power hundreds of households in Nepal, often arranged as run-of-river (no dams)
  • Nepal's steep terrain and remote communities make centralized power expensive, but decentralized microhydro a sustainable and cost-effective alternative
  • Electronic load controllers (ELCs), used in microhydro for regulating voltage and frequency, divert surplus power into a dump load (converting power to waste heat)
  • ELCs emerged in the 1980s as a cheaper and easier to maintain alternative to hydraulic governors (making lower capacity microhydro financially feasible)
  • However, ELCs have themselves been documented as one of the most common components to fail
  • Distributed electronic load controllers (DELCs) proposed by a team at the University of Calgary improves overall resilience to failures, while also diverting surplus power into household water pasteurizers or slowcookers
  • Slowcookers are valuable to rural populations, 92.1% of which still rely on firewood for fuel where resulting indoor air pollutants cause an estimated 7500 deaths/year in Nepal
  • Battery storage is too expensive for most of Nepal's rural population, so finding ways to use surplus power cheaply (e.g. slowcookers) rather than store it is worth considering
  • A powerhouse ELC is still required in a system with DELCs, but at much lower power rating (significantly reducing weight and risk to porters transporting ELCs into communities)
  • This thesis project aimed at redesigning this powerhouse ELC for a DELC-based system
  • Focus: a three-phase induction generator system (similar to Fig. 1), with a powerhouse ELC on each phase (given in more detail in Fig. 2), except each of the houses in Fig. 1 would be fitted with a DELC slowcooker as shown in Fig. 3

Fig. 1: Conventional three-phase arrangement (without DELCs). 
Fig. 2: Typical ELCs have four main subsystems: (1) sensing circuit, (2) control logic, (3) chopper switch, (4) dump load
Fig 3: Household with DELC.



Simulink Model
The model includes three subsections: generator, ELC, and user load. Each is modelled with equations: [Krause's model]

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Prototype
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[Arduino code]






Results
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[Processing Java code]


More Information
IEEE Paper
Master's Thesis