Description

The battery model consists of a controlled voltage source and a series internal resistance. The voltage source is controlled by a battery model that implements the dependence of the internal voltage on the current sensed at the output of the battery. The battery model equations depend on the selected battery technology. When enabling Customized parameters option (in form), the user can set its own discharge parameters. This model does not consider the temperature and aging effects on the battery. See Additional Information, below, for the equivalent circuit diagram and the battery model equations. To properly initialize this component select Solve Control inputs before solving power available in the Advanced tab in the Simulation Settings.

Table of Contents

Mask and Parameters

Nominal parameters

Parameter name	Description	Unit	Variable = {Possible Values}
Description	Use this field to add all kinds of information about the component.		Description = {'string'}
Type of battery	Provides a set of predetermined charge and discharge parameters for four types of battery: 1- Lead-Acid, 2- Li-Ion, 3- Li-Ion LFP, 4- Li-Ion NMC, 5- Li-Ion NCR/NCA , 6- Li-Ion LTO, 7- Nickel-Cadmium, 8- Nickel-Metal-Hydride.		battType = {1,2,3,4,5,6,7,8}
Nominal voltage	Nominal voltage of the battery.	V	Vnom = { [0, 1e64] }
Rated capacity	The Rated capacity of the battery is the minimum effective capacity of the battery.	Ah	Qnom = { [0, 1e64] }
Initial state-of-charge (SOC)	Initial state of charge of the battery.	%	SOC = { [0, 100] }
Battery response time	Response time of the voltage, at 95% of the final value, when the current has a step change. The value represents the voltage dynamics of the battery.	s	batt_Tr = { [0, 1e64] }

Discharge parameters (standard parameters)

Parameter name	Description	Unit	Variable = {Possible Values}
Maximum capacity	Maximum capacity of the battery.	Ah	maxQ = { [0, 1e64] }
Cut-off voltage	Minimum allowable battery voltage. This voltage represents the end of the discharge characteristics (the battery is fully discharged).	V	minV = { [0, 1e64] }
Fully charge voltage	Voltage at maximum charge of the battery. The fully charged voltage is not the no-load voltage.	V	fullV = { [0, 1e64] }
Nominal discharge current	Nominal discharge current for which the discharge curve is measured.	A	disRate = { [0, 1e64] }
Internal resistance	Internal resistance of the battery. When a type of battery is selected, a generic value is loaded that corresponds to a specific % of the nominal power (nominal voltage multiplied by the battery rated capacity). The resistance is constant during the charge and the discharge cycles and does not vary with the amplitude of the current.	Ohm	R = { [0, 1e64] }
Capacity (Ah) at nominal voltage	Capacity extracted from the battery until the voltage drops under the nominal voltage. This value should be between the current at exponential zone and the maximum capacity of the battery.	Ah	normalOP = { [0, 1e64] }
Voltage at exponential zone	Voltage that correspond to the end of the exponential zone. The voltage should be between the nominal voltage and the fully charge voltage.	V	expZoneV = { [0, 1e64] }
Capacity at exponential zone	Current that correspond to the end of the exponential zone. The current should be between the 0 and the rated capacity of the battery.	Ah	expZoneI = { [0, 1e64] }

Discharge parameters (customized parameters)

Parameter name	Description	Unit	Variable = {Possible Values}
Customized parameters	When enabled, the user can set the discharge parameters and the model will use them instead of the standard discharge parameters.		override = {0,1}
Maximum capacity	Customized maximum capacity of the battery.	Ah	maxQ_cust = { [0, 1e64] }
Cut-off voltage	Customized minimum allowable battery voltage. This voltage represents the end of the discharge characteristics (the battery is fully discharged).	V	minV_cust = { [0, 1e64] }
Fully charge voltage	Customized voltage at maximum charge of the battery. The fully charged voltage is not the no-load voltage.	V	fullV_cust = { [0, 1e64] }
Nominal discharge current	Customized nominal discharge current for which the discharge curve is measured.	A	disRate_cust = { [0, 1e64] }
Internal resistance	Customized internal resistance of the battery. When a type of battery is selected, a generic value is loaded that corresponds to a specific % of the nominal power (nominal voltage multiplied by the battery rated capacity). The resistance is constant during the charge and the discharge cycles and does not vary with the amplitude of the current.	Ohm	R_cust = { [0, 1e64] }
Capacity (Ah) at nominal voltage	Customized capacity extracted from the battery until the voltage drops under the nominal voltage. This value should be between the current at exponential zone and the maximum capacity of the battery.	Ah	normalOP_cust = { [0, 1e64] }
Voltage at exponential zone	Customized voltage that correspond to the end of the exponential zone. The voltage should be between the nominal voltage and the fully charge voltage.	V	expZoneV_cust = { [0, 1e64] }
Capacity at exponential zone	Customized current that correspond to the end of the exponential zone. The current should be between the 0 and the rated capacity of the battery.	Ah	expZoneI_cust = { [0, 1e64] }

Ports, Inputs, Outputs and Signals Available for Monitoring

Ports

Name	Description
Positive	Network connector on the DC side; The + indicates this is the positive terminal (supports only 1-phase connections).
Negative	Network connector on the DC side; The - indicates this is the negative terminal (supports only 1-phase connections).

Inputs

Name	Description	Units
reset	Logic signal to reset the state of charge (SOC) to its initial value during the simulation.

Keep one line to create space with the next section

Outputs

Name	Description	Units
Ibatt	DC output current of the battery.	A
SOC	State of charge of the battery.	%
Vbatt	DC output voltage of the battery.	V

Sensors

Name	Description	Units
reset	Logic signal to reset the state of charge (SOC) to its initial value during the simulation.
Ibatt	DC output current of the battery.	A
SOC	State of charge of the battery.	%
Vbatt	DC output voltage of the battery.	V

Additional Information

The figure below shows the equivalent circuit implemented in the battery model.

Equivalent circuit implemented in the model

For the Lead-Acid battery type, the model uses the following equations:

Discharge Model ( i_filter > 0 ):

Charge Model ( i_filter < 0 ):

For the Lithium-Ion battery family type, the model uses the following equations:

Discharge Model ( i_filter > 0 ):

Charge Model ( i_filter < 0 ):

For the Nickel-Cadmium and Nickel-Metal-Hydride battery type, the model uses the following equations:

Discharge Model ( i_filter > 0 ):

Charge Model ( i_filter < 0 ):

where:

is the constant voltage, in V.

is the exponential zone dynamics, in V.

represents the battery mode. during battery discharge, during battery charging.

is the polarization constant, in V/Ah, or polarization resistance, in Ohms.

is the low-frequency current dynamics, in A.

is the battery current, in A.

is the extracted capacity, in Ah.

is the maximum battery capacity, in Ah.

is the exponential voltage, in V.

is the exponential capacity, in Ah^-1.

Charge and Discharge Characteristics

The circuit parameters can be modified to represent each of the four battery types presented in the model as well as its discharge characteristics. A typical discharge curve consists of three sections.

Typical Discharge Characteristics

The first section shows the exponential voltage drop when the battery is charged. The width of the drop depends on the battery type. The second section indicates the charge that can be extracted from the battery until the voltage drops below the battery nominal voltage. Finally, the third section illustrates the total discharge of the battery, when the voltage drops rapidly.

When the battery current is negative, the battery recharges, following a charge characteristic.

Typical Charge Characteristics for Lead-Acid, Li-ion, NiMH and NiCD

The model parameters are calculated from the discharge characteristics. The discharging and charging characteristics are considered to be the same.

The transfer function represents the hysteresis phenomenon for the Lead-Acid, Nickel-Cadmium (NiCD), and Nickel-Metal-Hydride (NiMH) batteries during the charge and discharge cycles. The exponential voltage increases when a battery is charging, regardless of the battery's state of charge. When the battery is discharging, the exponential voltage decreases immediately as shown in the following figure.

Exponential Zone for Lead-Acid, NiMH and NiCD

The state of charge (SOC) for a battery is a measure of battery's charge, expressed as a percent of the full charge. The depth of discharge (DOD) is the numerical compliment of the SOC, such that DOD = 100% - SOC.

Battery Modeling

The battery model developed as a sub-circuit containing a power part, consisting of a HYPERSIM-based controlled voltage source and a series internal resistance, and a control part, consisting of a battery model that implements the dependence of the internal voltage on the current sensed at the output of the battery. The battery model has been designed using native HYPERSIM control components and User Code Model (UCM) type components. The figure below shows the internal circuit of the battery model.

Internal circuit of the battery

Limitations

The minimum no-load battery voltage is 0 V and the maximum battery voltage is equal to .
The minimum capacity of the battery is 0 Ah and the maximum capacity is .
This model does not consider the temperature and aging effects on the battery.
The internal resistance is assumed to be constant during the charge and discharge cycles and does not vary with the amplitude of the current.
The parameters of the model are derived from the discharge characteristics. The discharging and charging characteristics are assumed to be the same.
The capacity of the battery does not change with the amplitude of the current (there is no Peukert effect).
The self-discharge of the battery is not represented. It can be represented by adding a large resistance in parallel with the battery terminals.
The battery has no memory effect.

References

MathWorks, « Battery. » Mathworks.com. https://www.mathworks.com/help/physmod/sps/powersys/ref/battery.html (accessed June. 15, 2020).

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