Introduction of example application: Seiko Electric Corp. “DC microgrid system for renewable energy using the EZA series of bidirectional DC-DC converters”

Seiko Electric’s DC microgrid system is a power source system that minimizes purchases of electric power from commercial sources and makes possible self-supply of energy during disasters. The EZA series of bidirectional DC-DC converters charges and discharges lithium batteries and uses bidirectionality to enable online EL diagnostics of photovoltaic panels. In addition, using the EZA series also enables connection to electric vehicles, allowing the use of an electric vehicle as a power supply during disasters.
An overview of the system is shown in the figure below.

Exterior view of system (partial)

Example of EL diagnostics
A deterioration diagnostic system that makes use of the characteristic of photovoltaic panels that they emit light when voltage is applied in the reverse direction (panels actually emitting light are shown below).

Overview of the DC microgrid system
・DC power supply system for renewable energy ・Use with photovoltaic systems after expiration of the feed-in tariff period ・Supports systems that generate electric power internally for internal use ・Flexible customization according to customer applications as possible
Roles of the EZA series of bidirectional DC-DC converters in the DC microgrid system
・Charging and discharging lithium batteries ・MPPT control of solar power generation and application of power supply for EL testing ・Charging and discharging electric vehicles
Other examples of use of the EZA series
・Biomass boiler electric power generation systems ・Automated guided vehicles (AGVs) using renewable energy (wind or solar power) ・40-foot container type large-scale storage battery systems (200kWh@50kW peak shift charging and discharging systems)