The goal of this project is to build a base system that allows private homes to optimally make use of a renewable energy source such as a photovoltaic system.
Often these systems already come with an interface to read the current power production. This could be used as a sensor information in an ROS automated smart home to turn on/off different energy consumers such as a heat pump for warm water or charging an electronic vehicle. Another way to make use of an automated reading of this sensor information to calculate statistics such as daily/weekly energy production/consumption.
The project will be built for our own house with our specific gear in mind. However, the idea can be applied to other systems as well.
demo.mp4
The project is run with ros melodic. We have the following nodes:
This is a publisher node that connects to a central modbus server, reads the data and publishes them onto various ros topics.
The following topics are published:
- total_grid_power: wattage positiv:energy is consumed from grid, negativ:energy is delivered to grid
- total_pv_power: wattage always >= 0
- battery_state_of_charge: percentage 0-100
- battery_power: wattage positiv:battery is charging, negativ: battery is discharging
- battery_life_soc_limit: percentage the battery will not get discharged beyound that level https://www.victronenergy.com/media/pg/Energy_Storage_System/en/controlling-depth-of-discharge.html#UUID-af4a7478-4b75-68ac-cf3c-16c381335d1e
For total_grid_power and total_pv_power I read all 3 Phases seperatly and combine then to one number each.
This node is preconfigured to listen to our specific modbus server(ip,port,slaveID) and read the correct addresses. The addresses can be found in CCGX-Modbus-TCP-register-list-2.90.xlsl
Code: catkin_ws4/src/modbus-cpp/src/modbus.cpp catkin_ws4/src/modbus-cpp/src/modbus.h - this is an external lib from https://github.com/fz-lyu/modbuspp
This is a listener and publisher nodes. I listen to the topics from the modbus node apply some logic that decides when a relay should be open or closed. This value will get written on the topic relay1_state (1 => open, 0 => closed).
Currently, we have a simple threshold for the total_grid_power which the relay opens or closes. In the future we want to extend that logic to also use the battery state and total_pv_power.
This threshold can be configured in the launch file. currentValue < threshold -> open otherwise close.
Code: catkin_ws4/src/modbus-cpp/src/computeNode.cpp
This is a listener node which runs on an Arduino that is physically wired to a relay that can switch 220V 10A. This relay is connected to a standard power plug, so we can switch any device (that does not exceed the limits) with it.
We listen to the relay1_state topic and either open or close the relay.
It is connected to the roscore with rosserial_python serial_node.py
Code: catkin_ws4/src/modbus-cpp/src/rosserial_arduino_relay_toggle/rosserial_arduino_relay_toggle.ino
Requirements: Ubuntu 18.04 Ros Melodic http://wiki.ros.org/melodic/Installation/Ubuntu
It only works when the correct modbus server is available. The preconfigured server can be found in catkin_ws4/src/modbus-cpp/src/modbus.cpp
I put a demo video and screenshots in the folder demo as well as pictures of the used hardware.
Otherwise it is all connected to a central launch file: catkin_ws4/src/modbus-cpp/launch/modbus.launch
cd catkin_ws4
catkin_make
source devel/bash.setup
roslaunch modbus-cpp modbus.launchhttps://www.victronenergy.de/panel-systems-remote-monitoring/cerbo-gx https://www.victronenergy.de/panel-systems-remote-monitoring/cerbo-gx#technical-information
Victron: 192.168.1.125 port: default 502 NOTE: Use unit-id 100 for the com.victronenergy.system data, for more information see FAQ.
Addresses that we use
- batteryState 843
- battery_power 842
- batteryLife_soc_limit 2903
- pvProduction phase1,2,3 808,809,810
- gridPower phase1,2,3 820,821,823