The OMRON PWB (DD) 1178158-0S is a DC Power Board designed for OMRON KP100L, KP125L, and KP150L three-phase photovoltaic inverters. This module is one of the primary power conversion and energy management boards within the inverter and is specifically engineered for systems featuring three independent MPPT (Maximum Power Point Tracker) channels.

The board receives DC power from photovoltaic strings, manages current distribution across the MPPT channels, and performs filtering, energy storage, and DC bus stabilization functions. Its high-capacity electrolytic capacitor bank helps maintain a stable DC voltage required by the subsequent inverter power stages.

As a critical component of the inverter architecture, the DC Power Board operates in close coordination with the main control board, IGBT power modules, and AC conversion stages.

⚙️ Technical Specifications

• Manufacturer: OMRON
• Model: PWB (DD)
• Part Number: 1178158-0S
• Type: DC Power Board
• Application: Three-phase grid-tied photovoltaic inverters
• MPPT Configuration: 3 independent MPPT channels
• Compatible Models:
  • OMRON KP100L
  • OMRON KP125L
  • OMRON KP150L
• Multiple PV input management
• High-capacity capacitor bank
• DC distribution and filtering circuits
• High-current power connections
• Designed for commercial and industrial photovoltaic systems
• Internal inverter installation

🔧 Main Functions

DC Bus Management

Receives and stabilizes the DC voltage generated by photovoltaic modules before conversion into AC power.

3 MPPT Support

Provides management of three independent Maximum Power Point Trackers, optimizing energy production from PV strings with different orientations, irradiance levels, or shading conditions.

DC Voltage Filtering

Reduces:

• Voltage ripple
• Electrical oscillations
• High-frequency disturbances
• DC bus instability

Temporary Energy Storage

The integrated capacitor bank stores energy to maintain stable operation during fluctuations in solar irradiance and load conditions.

Protection of Power Conversion Modules

Helps protect:

• IGBT modules
• Gate driver circuits
• Power electronics
• DC bus components

from voltage spikes and transient conditions.

🔌 Purpose and Operation

This board is responsible for managing the energy produced by photovoltaic panels before the DC/AC conversion process.

Its key functions include:

• DC voltage stabilization
• Management of three independent MPPT channels
• Energy storage within the DC bus
• Reduction of electrical interference
• Supplying power to inverter modules
• Supporting maximum power point tracking operations

Without this board, the inverter would be unable to properly process and regulate energy from the photovoltaic array.

🧩 Role Within the Inverter System

Inside OMRON KP Series inverters, the board serves as:

• Interface between PV strings and inverter stage
• Main DC bus management system
• Energy storage and filtering module
• MPPT support platform
• Power supply stage for IGBT modules

It works directly with:

• Main control board
• IGBT power modules
• Gate driver boards
• Monitoring circuits
• AC output filter board

⚠️ Typical Faults and Symptoms

Aging Electrolytic Capacitors

Symptoms:

❗ Reduced capacitance
❗ Unstable DC voltage
❗ Increased ripple voltage
❗ Random inverter shutdowns

Swollen Capacitors or Electrolyte Leakage

Symptoms:

❗ Overheating
❗ Reduced energy production
❗ DC bus faults
❗ Unexpected inverter shutdowns

Damaged High-Current Connections

Symptoms:

❗ Oxidation and corrosion
❗ Overheated terminals
❗ Voltage drops
❗ Intermittent faults

PCB Tracks or Components Damaged by Overvoltage

Symptoms:

❗ Short circuits
❗ Blown fuses
❗ Inverter startup failure

MPPT Circuit Failures

Symptoms:

❗ Loss of production on one or more strings
❗ Inefficient power tracking
❗ Reduced energy yield
❗ Lower overall system efficiency

🚨 Possible Associated Errors

A defective DC Power Board may generate errors such as:

• DC Bus Over Voltage
• DC Bus Under Voltage
• DC Link Fault
• Capacitor Fault
• MPPT Error
• Input Current Error
• PV Input Fault
• Internal Hardware Error
• Over Current Fault
• Power Stage Fault
• Ground Fault
• Inverter Stop

In some cases, the inverter may continue operating but with significantly reduced power production and lower efficiency.

🌞 Advantages of the 3 MPPT Architecture

The presence of three independent MPPT channels offers:

✔ Higher energy yield
✔ Support for PV strings with different orientations
✔ Reduced losses caused by partial shading
✔ Improved overall system efficiency
✔ Greater installation flexibility
✔ Optimized photovoltaic performance

🛠 Applications

• Repair of OMRON KP Series photovoltaic inverters
• Replacement of faulty DC Power Boards
• Restoration of MPPT functionality
• Industrial and commercial solar inverter maintenance
• Refurbishment of photovoltaic power conversion systems
• Troubleshooting DC bus and power stage faults

🔄 Compatibility

Compatible with:

• OMRON KP100L
• OMRON KP125L
• OMRON KP150L

Always verify the board part number (1178158-0S) and hardware revision before replacement.

🟢 Summary

The OMRON PWB (DD) 1178158-0S DC Power Board is a critical power management module used in OMRON KP100L, KP125L, and KP150L photovoltaic inverters. Featuring a 3 MPPT architecture, high-capacity DC bus capacitors, and advanced power distribution circuitry, it provides DC stabilization, energy storage, and maximum power point tracking functions essential for efficient and reliable photovoltaic energy conversion.