Permanent magnet synchronous generator for biogas micro-cogeneration plant | Синхронный генератор с магнитным ротором в установке биогазовой микрокогенерации

Biogas produced from agricultural biomass and manure contains 5 to 7% methane, 29 to 44% of carbon dioxide and about 1% of other admixtures. Heating capacity of biogas varies from 20 to 25 mega J/cubic meter. The prospect cultivated plant for biogas production is goat's rue (Galega orientalis). When Galega is added to cow manure, biogas production increases in 1.5 times. One of the ways to save primary energy resources, to reduce air emissions and to provide an autonomous heat and electrical energy supply is to install biogas micro-cogeneration plants (MCPs). Conventional MCPs consists of a gas engine and currently exciting synchronous generator (CESG). CESG was replaced with a permanent magnet synchronous generator (PMSG). The main advantages of PMSG are considerably smaller; and size in relation to the power unit, higher operational reliability, higher efficiency and very small energy loss. The weak point of PMSG is that to ensure sufficiently high stability of output voltage and by a direct parallel connection to the electric power network without a semi-conductor is required. The steady-state and run up characteristics are investigated, as well as the 2 loop control system for the output voltage U and by f stabilization in a MCP is simulated. The load P impact on angular speed input voltage U and frequency f is identified. An adequate model for transient simulation is made. If an angular speed of the engine shaft is kept invariable, frequency of output voltage remains constant (f=const.). The output voltage U changes up of rated value, if electrical load of PMSG varies from no-load to rated value. Deviation is inconsistent with the existing norms. The simulation block-diagram of the 2 loop control system of frequency f (Hz) as a k from angular speed co (rad/s) and voltage U(V) as a feedback from voltage deviation value (AU=Un0m-U) is compiled. Simulations show that the load of the PMSG varies step-by-step from Pi= 12% of Pn0m to Pi= 97% of Pnom. The conclusion is that the MCP with 2 loop control system of output voltage U and frequency ensures an adequate quality of electrical power and can be used for electric energy self-provision without a semi-conductor converter