Peak load limiter

[Erwin van der Zwart]

Hi,

Here is a more complex script for load balancing, i use it for EV chargers, they can use max 63 Amp and need minimal 8 Amp, based on active chargers and available power the chargers are set to a maximum loader output over modbus (for our EVLink)

All works with TAG's on the binary state (active/not active) object and a offset of 1 in the main address (32/1/1 = State -> 32/1/1 = Set max charging output) so you can easily add multiple chargers (:

Code:

-- Get maximal available amperage
Max_Amp = grp.getvalue('35/0/10')

-- Get current messured amperage
Current_Amp = grp.getvalue('35/0/11')

-- Calculate available amperage for loaders
Available_Amp = Max_Amp - Current_Amp

-- Minimal amperage output on loader
Min_Loader_Amp = 8

-- Maximal amperage output on loader
Max_Loader_Amp = 63

-- Get all loaders on/off states
All_Loaders = grp.tag('LoaderState')

-- Function to sort table by updatetime
local function tableSortCat (a,b)
 return a.updatetime < b.updatetime
end

-- Sort table All_Loaders by updatetime
table.sort(All_Loaders, tableSortCat)

-- Create table with active loader
Active_Loaders = {}

-- Determine amount of active loaders
Number_Active_Loaders = 0

-- Ceeate new table with values and only loader tagged bit objects
for _, item in pairs(All_Loaders) do
 if item.datatype == 1 or (item.datatype > 999 and item.datatype < 2000) then
   if item.value == true then
     Number_Active_Loaders = Number_Active_Loaders + 1
   end
   table.insert(Active_Loaders, {id = item.id, updatetime = item.updatetime, datatype = item.datatype, address = item.address, value = item.value})
 end
end

-- Sort table Active_Loaders by updatetime
table.sort(Active_Loaders, tableSortCat)

-- Determine maximum loaders based on available power
Max_Number_Loaders_Possible =  math.floor(Available_Amp / Min_Loader_Amp)

-- Check if more loaders are active then max possible loaders
if Number_Active_Loaders < Max_Number_Loaders_Possible then
 Max_Number_Loaders_Possible = Number_Active_Loaders
end

--Set available amperage per loader
Available_Amperage_Loader_Per_Unit = math.round(Available_Amp / Max_Number_Loaders_Possible, 2)

--Check if output exceeds loaders Max_Amp
if Available_Amperage_Loader_Per_Unit > Max_Loader_Amp then
 Available_Amperage_Loader_Per_Unit = Max_Loader_Amp
end

-- Set loaders to 0 when current amperage exceeds max amperage
if Current_Amp > Max_Amp then
    Max_Number_Loaders_Possible = 0
 Available_Amperage_Loader_Per_Unit = 0
end

-- Write values to the output of each loader
Number_Loaders_Value_Written = 0
for _, item in pairs(All_Loaders) do
 Address_Table = string.split(item.address, "/")
 New_Address = Address_Table[1]+1 .. '/' .. Address_Table[2] .. '/' .. Address_Table[3]
 if item.value == true then
   if Number_Loaders_Value_Written < Max_Number_Loaders_Possible then
       grp.checkupdate(New_Address,Available_Amperage_Loader_Per_Unit)
     Number_Loaders_Value_Written = Number_Loaders_Value_Written + 1
   else
     grp.checkupdate(New_Address,0)
   end
 else
   grp.checkupdate(New_Address,0)
 end
end

BR,

Erwin