YASKAWA Solectria PVI 25TL-208 Installation And Operation Manual page 44

Installation and Operation Guide SOLECTRIA® PVI 25TL-208, PVI 50TL-480 and PVI 60TL-480
Electrical Installation DC
The SOLECTRIA PVI 25TL-208, PVI 50/60TL-480 inverters provide design flexibility for the installer and designer.
The following section provides important information regarding the DC input specifications, wiring requirements,
and installation instructions.
The SOLECTRIA PVI inverters are factory configured with MPPTs which are electrically divided into separate PV input
zones: PV Input-1 (PVIn1), PV Input-2 (PVIn2) and PV Input-3 (PVIn3) (see Table 3-4).
Each PV input zone operates as a separate and independent Maximum Power Point Tracker (MPPT). Independent
MPPTs can be very useful for sites with partial shading of the array or with arrays consisting of different tilt or
azimuth. Each MPPT employs a method known as perturb and observe (P&O) for seeking and tracking the maximum
power point along the IV curve of the PV array. During operation each MPPT will make small adjustments to the PV
voltage and then execute a power measurement; if the PV power increases, further voltage adjustments in that
same direction are performed until the PV power no longer increases.
DC Overload: Exceeding the recommended DC to AC ratio may damage the inverter and will void the warranty.
Size strings according to information in this section and all applicable electrical codes.
DC/AC Ratio and Current Limits: Both DC to AC ratio and I
requirements may result in damage and will void the warranty.
High Irradiance Installations: In applications that may experience higher than 1000 W/m2 on a regular basis, it
is recommended to design a DC-to-AC ratio below the limit of 1.5 (PVI 60TL-480) and 1.8 (PVI 50TL-480 and PVI
25TL-208).
To ensure optimal performance, the number of PV modules per source circuit should be identical within a given
MPPT zone. However, PV input power may be unbalanced between the MPPT zones. See Figure 3-26 for
string/zone combinations.
 DESIGN TIP #1: Note the max input power per MPPT zone and the total inverter max PV power (see Table
3-4)
 DESIGN TIP #2: When designing the PV system, ensure each PV source circuit within a single PV input zone
includes the same module type (manufacturer and rating), series module count, and module orientation
(tilt and azimuth) to maximize MPPT performance and energy harvest.
 DESIGN TIP #3: The difference in the number of source circuits for each MPPT should not exceed one (i.e.
PVIn1:PVIn2 = 3:2). Uneven distribution of strings among MPPTs (e.g. PVIn1:PVIn2 = 3:1), for example, is
not recommended and may result in unnecessary power clipping.
DOCR-071030-A (10/7/2022)
MPPT Zones
String Mismatch
NOTICE!
limits must be observed. Failure to meet these
sc
NOTICE!
Page 44 of 131