Solar Charge Regulator Configurations

This post shows list the different types of solar charge regulator configurations. Listed are few ways a Solar Charge Regulators can be configured in a Solar PV systems.

Based on the type, size , cost , availability of hardware and system designer, charge regulator configurations are configured. Below are the most common configurations of charge regulators in a Solar Power Systems.

  1. Simple series path configuration.
  2. Auxiliary load path configuration.
  3. Parallel path configuration.
  4. Sub-array switching configuration.

SIMPLE SERIES PATH CONFIGURATION:

Solar Charge Regulator Configurations

Fig 1 : SIMPLE SERIES PATH CONFIGURATION

See Fig . 1 :  One basic approach is to have the regulator placed in series between the array and the battery. The regulator acts as a switch, either opening the circuit and turning off any array charging when the battery reaches full state of charge,  or shunting array current away from the battery and dissipating the array power as heat.

AUXILIARY LOAD PATH CONFIGURATION

See Fig.2 : In this approach, you can observe that the array power that is not needed to further charge the battery is diverted to some auxiliary non-essential load

Charge Regulator Configurations -Aux Load configuration

Fig 2 : AUXILIARY LOAD PATH CONFIGURATION

Note :

The voltage to this auxiliary load is not regulated, so the auxiliary load is usually a DC motor for a water pump or fan, or some resistive element for water heating.

Whenever excess energy is available, these types of load can absorb it, When battery voltage drops and array power is once again needed to recharge it, the auxiliary load’s power is cut off.

As you see, this approach makes full use of all the array energy produced through out the year. There is usually excessive array energy available in the summer. Without this diversion function, excess array energy is simply thrown away by the simple series approach.

Auxiliary load diversion is usually used in  remote habitation applications, where a non-essential load can be of use. It is usually not of much value in remote industrial applications, as they do not usually have need for the common loads used for the auxiliary power( cooling during summer months is a typical exception).

PARALLEL PATH CONFIGURATION

See Fig.3 : In this configuration, the auxiliary load is no longer an option. As you see, the charge regulator is not in series between the array and battery, but is placed in parallel with the battery .

Charge Regulator Configurations - Parallel path Configuration

Fig.3 : PARALLEL PATH CONFIGURATION

NOTE :

Array power is passed directly to the battery at all times.  When the battery reaches near full state of charge, the regulator begins to pass power to the auxiliary load.

If the battery is fully charged, then all the power from the array flows across the battery terminals and to the auxiliary load.

Advantages :

The advantages  of this type of configuration is that multiple sources of power can be connected to the battery. Sources such as wind generators that produce large variations in current could damage series regulators.

But in this approach, the large battery bank acts as a buffer, absorbing all the wind generator energy, and the regulator must only gradually divert the energy away.

SUB-ARRAY SWITCHING CONFIGURATION

SUB-ARRAY SWITCHING CONFIGURATION- Charge Regulator Configurations

Fig.4 :SUB-ARRAY SWITCHING CONFIGURATION

See Fig.4 : For large arrays, one approach is to have  groups of modules or sub-arrays connected to their own charge regulator. Each regulator can be set to a slightly different cut-off voltage. As the battery voltage rises, first one sub-array and the the next can be shut off, gradually reducing the charge current into the battery.

Also Read :

The above Solar Charge Regulator Configurations are used normally in a Standalone Solar PV systems.

Reference : Standalone Photo voltaic Systems