Optimizing Power Output in Hybrid Plants
A well-designed hybrid plant is crucial for optimizing power output. Effective design considers not only the panels and inverter but also the technical parameters of the battery.
How can we maximize power output from residential batteries?
To achieve maximum charging and discharging power from residential batteries, it's essential to:
Ensure the ambient temperature for the battery and hybrid inverter remains within their specified allowable range.
The SBR battery series has a maximum charge/discharge current of 30 A, which can be reached at temperatures below 50℃ (see Fig. 1).
Fig.1.
*Note that the Battery Current (I_bat) considers just the effect of temperature in this graph.
2. Ensure the PV string length for the hybrid inverter remains within its no-derating range as much as possible.
The battery achieves maximum current at values close to its nominal rated voltage. High output voltage from PV strings can affect battery current operation. Therefore, it is recommended to avoid overly long PV strings, as they result in higher input DC voltage, which can impact performance (see Fig. 2).
Fig.2.
*Note that the Battery Charging Current (I_bat) does not consider the influence from the battery voltage itself in this graph.
To better understand how the battery's discharge power is reached, refer to the Current-Voltage curves in Fig. 3. The rated power (maximum discharge power) is achieved at the maximum discharge current of 30 A. The battery operates within the voltage range showcased in the x-axis, where the discharge process occurs.
Fig.3.
*Note that the trend on Battery current is assumed to be in an enviroment where:
Temp < 50°C
What Power Output can be expected from each SBR Battery Model?
With the minumum battery Current (Idc= min Ibat) from the above graph and the minimum operating voltage for the battery (Vdc), the minimum design power (Pdc) when working within the battery voltage range at normal circumstancesis displayed in the table - for each SBR model. This represents the design power expected to be delivered by the inverter under normal circumstances.
Table: Minimum SBR design power
Understanding this power output helps optimize system performance and ensures that the energy demands are met effectively.