Development and Application of an Energy Management System for Electric Vehicles Integrated with Multi-input DC-DC Bidirectional Buck-Boost Converter

in Development and Application of an Energy Management System for Electric Vehicles Integrated with Multi-input DC-DC Bidirectional Buck-Boost Converter ░ ABSTRACT-The rise in environmental pollution, demand for fossil fuels, and higher fuel economy vehicles has raised concerns about the creation of new and efficient transportation vehicles in recent days. These days, most developments in electric vehicles concentrate on making the vehicles more pleasant to ride in. Nonetheless, the emphasis now should be on energy and its most efficient use. To do this, you must give your attention to the origin of the automobile. The answer to this problem may be found in hybrid energy storage systems (HESS). This work is concerned with the design and implementation of an effective energy management system in electric vehicles (EVs) equipped with an active HESS consisting of a battery and a super capacitor via the incorporation of load sharing into this hybridization under a variety of load demand scenarios. To address the demands of high fuel efficiency vehicles, automotive firms are focusing on the development of diesel-engine operated vehicles, electric vehicles, fuel-cell vehicles, plug-in electric vehicles, and hybrid electric vehicles. A Multi-input Bidirectional Buck-Boost (MIB 3 ) DC-DC converter is proposed in this dissertation to provide a greater conversion ratio to the input DC voltage. The multi-input converter recommended has fewer components and a simpler control method, making it more trustworthy and cost-effective. This converter also has bidirectional power flow functionality, making it suitable for charging the battery during regenerative braking in an electric or hybrid vehicle. Three different energy sources are used in the suggested topology: a photovoltaic (PV) panel, a battery, and an ultra-capacitor.


░ 1. INTRODUCTION
The main drawbacks of internal combustion engine-powered autos are rising fuel costs, pollution issues, and fossil fuel depletion. To address the aforementioned challenges, the automobile industry has begun to demonstrate an interest in vehicles that use alternative energy sources. As a result, electric vehicles (EVs) and plug-in hybrid EVs are becoming increasingly popular. Thus, energy storage equipment such as batteries and ultra-capacitors can be used to convert traditional vehicular systems into electric or hybrid electric vehicle. . During acceleration, the EV and HEV use electrical energy to complement the output of an internal combustion (IC) engine, and during braking, the energy supplied by the electric motor is restored[1] [2] [3] [4].
The following criteria define the EV and HEV's capability: 1) the ability to reduce the battery storage unit's power consumption during acceleration. 2) The system's ability to recover electrical energy lost during braking. 3) the ability to eliminate the IC Engine's perfect operation, and 4) the capacity to produce enough torque to fulfil demand. Researchers have come up with a lot of different ways to make HEVs and EVs more efficient and cheaper. Xiong et al. (2008), Chan 2007, andRajashekara (2013) are some of them [5]. To govern the power flow from car to home and home to vehicle, the smart controller has been connected to the status of This study presents the design and implementation of a modular four-port bidirectional buck-boost converter for integrating many energy sources, including batteries, ultra-capacitors, and solar panels. Once the bidirectional converter's output is fed into the three-phase inverter, the dc power is converted to ac, and an LC filter is used to get a smooth sinusoidal curve, allowing a traction motor to operate at constant speeds with no distortion. The separate converter may use either a parallel or series connection to the energy source. For a series connection to work, all of the conductors must be able to carry the same current, and a parallel converter must provide the same voltage across all of the connections. Both of these are quite undesirable. Multi-input, single-output (MISO) systems, however, are commendable due to their low cost and excellent efficiency [7] [8] [9]. The proposed converter has many operating modes, including single input, dual output (SIDO), dual input, single output (DISO), and even single input, tri output (SITO).
These research gaps are addressed in this study by providing the following contributions: (1) Developing a multi-input converter architecture and controller for use in the design of an EV powertrain that incorporates BU-UC as hybrid sources including precise switching patterns for driving and regenerative braking mode was a priority for the designers.
(2) Use the transfer function model to make a precise buckboost bidirectional DC-DC converter controller that is not inverted [10] [11].
(3) Implements an adaptive EMS that places a premium on the dynamic properties of hybrid sources in order to control energy consumption.
(4) Two different types of energy storage technologies, including a battery and an ultra-capacitor, are used to provide reliable power to HEVs [12]. (5) In this situation, the HEV receives its effective power, and the suggested solution increases the motor and vehicle's speed while simultaneously enhancing their torque output. Power may be transferred from a variety of sources to a load, and it does so efficiently and effectively [13] [14] [15] [16]. The converter's compact design and reduced component count improve its dependability, Proposed Multi-input Bidirectional Buck-Boost DC-DC Converter for electric vehicle as shown in figure 1 and Appraisal     The last portion of the paper presents the findings and discussion of the study.
1.1 Statement of the Problem 1.1.1. It is urgently necessary to create a sustainable and affordable method of storing energy from a wide range of sources.
1.1.2. Batteries very rarely start off at zero voltage, and even if they do, a relatively tiny charge is all that's needed to get them to a significant proportion of the open-circuit voltage.
1.1. 3. This article investigates the EV's load requirements, but only for the propulsion load type. Despite the fact that the analysis considers non-propulsion load requirements. Figure 1, depicts the power circuit topology of the proposed PV interfaced multi-input bidirectional buck-boost DC-DC converter driven Drive Hybrid Electric Vehicle (DHEV). The suggested system has less switches and power conversion stages than other systems. The PV array coupled to the inductors L1 and L2 provides a first stage of voltage boosting to the PV array's voltage. Connecting a high-frequency (HF) boosting transformer to the three-port converter improves its boosting potential even more. The isolation between the DC link and the PV arrays is also provided by the HF transformer. Bidirectional control of power transmission from battery to DC link and vice versa is provided via a bidirectional buck-boost DC-DC converter connected to the DC connection. The bidirectional converter can also be used to harness power from the PMSM motor by connecting diodes in parallel with the inverter's MOSFET. The suggested converter topology maintains a constant current between the DC link and the PV array. During the next sections, we show the steady state analysis of the proposed PV-DHEV in both acceleration and deceleration modes.

Multi-input Topology Operation
A PV panel, a battery backup, an ultra-capacitor, and a DC/DC multi-input converter with a power inverter are shown in the functional diagram of an electric vehicle system (See fig.1). system of propulsion. The input PV source is connected across in this case. The output of the proposed multiport converter is connected to the vehicle's drive train, which is connected to the converter. An ultra-capacitor can be built inside the battery unit. Increase the amount of output. Two inductors L1 & L2, two capacitors C1 & Cb, five active switches S1, S2, S3, S4, S5, and one diode make up the DC-DC bidirectional converter (See fig.  1) The duty cycles for switches S1, S2, S3, S5, and S4 are set correctly (d1, d2, d3, d11, d22). The suggested universal DC-DC converter is a MIB 3 C (multi-input bidirectional buck-boost converter), with PV as the primary generation unit and the battery and ultra-capacitor as the secondary storage units. The circuit's storage units can store regenerative energy and deliver additional energy during acceleration.
In continuous conduction mode (CCM), MIB3C functions in four different ways (See fig. 1): Case 1: The power is transferred between the source and the load using VPV or VDC (ultra-capacitor and battery charge). Battery (VBattery) to load (battery acquittals and ultra-capacitor charges). Case II: Ultra-capacitor (VU-C) to load (battery charges and ultra-capacitor acquittals). Case III: The ultra-capacitor and battery are powered by regenerative power (ultra-capacitor and battery in charging action).

CASE-I: PV-Voltage (Vbattery and VU-C (Buck),Voutput(Boost)
In this case, the converter operates in two modes, with diode D1 always on. Mode of Operation-I: S1, S2, S4, and D1 are switched on, but S5, S3, and D1 are turned off. As a result, both inductors L1 and L2 are powered in order to supply PV power to the load. The battery charges in this mode (See fig. 2 (a)).
Mode of Operation-II: Switches S1 and S2 are switched off in this mode. The S3, S5, and S4 have been activated. As a result, L1 releases the increased output into the stream. The battery is continually charged via the inductor L2 during this period (See fig. 2 (b)). As a result, the converter gives off buck output at the same time across the battery in this case. 2.1.1.1.1. Ideal multi-input bidirectional converter in order to look into the converter case-1 steady state in CCM, the parasitic performance (See table 2) Inductor resistance, switch resistance, and other parameters such as the voltage drop in the switches (S1 in d1 duty cycle), and diodes are regarded as insignificant. Employing the converter delivers a boosted output and is derived from the voltage-second balance idea for modes (I) and (II). As a result of the capacitor C1 − = (1− 1 )

Continuous Conduction Modes Derivation (CCM)
(1) Where Vdc-pv is input PV voltage, VL1 is the inductor L1 voltage. After Switch S2 is ON, the battery voltage can be derived as Where VBat denotes the voltage of the battery, as a result, the voltage change in the battery is given by In the case of ultra-capacitors, it's the same way The losses across the diodes, inductor, and switches are represented by PD1, PrL, and PSW, respectively. The current load can now be written as As a result, the converter's output is enhanced In the same way, the non-ideal buck output may be calculated as When the PV source charges the battery during buck operation, the battery charging current, (Ibatt), is calculated As a result, the charging voltage of the battery can be written as

CASE-II: VBattery (V U-C (Boost) and Vo (Buck), Voutput(Boost)
Mode of Operation-III: Switches S1, S2, and S3 are turned on in this mode, while S5 and S4 are turned off. As a result, inductor L1 and L2 are powered by the battery (See fig. 2 (c)).

Mode of Operation-IV:
When the switches S1 and S3 are turned off, the switches S2, S5, and S4 are switched on. As a result, inductors L1, L2, and the battery are discharged via switches S4 and S5. (See fig. 2 (d) for more information.) Because L1 and L2 are in series with the load, inductor current ripples (IL1 and IL2) are reduced in this mode of operation. As a result, the battery sinks power to the ultra-capacitor and the load in this situation.

CASE-III: Ultra-capacitor (VU-C) to load (battery charges and ultra-capacitor acquittals).
When VUC is connected to VBat and Vo, the ultra-capacitor provides power to the load. The battery charges at the same time. In this case, switches S1, S3, S2, S4, and S5 will form the current path. S2 is always in the ON position during this process.

Mode of Operation-V:
Switches S5 and S3 are turned off, while switches S1, S2, and S4 are turned on. Because of the ultracapacitor potential, L1 and L2 are now energised. As a result, the inductor current increases in a linear manner. The output voltage is obtained by discharging capacitor C1 (See fig. 2 (e)). Mode of Operation-VI: S5, S2, and S3 are turned on, but S1 and S4 are turned off. L1 and L2 inductors discharge through C1 (See fig. 2 (f)). The converter's working condition results in less ripple at the output. As a result, by supplying the battery with buck operation, the ultra-capacitor acts as a primary source. The converter has increased the output voltage given to it during this time.

CASE IV
The ultra-capacitor and battery are powered by regenerative power (ultra-capacitor and battery in charging action).

Mode of Operation-IX:
The switches S1, S2, S4, S3, and S5 are all turned on, while S5 is turned off. The load is discharged by the L1 and L2 inductors (See fig. 2 (h)). In this situation, the battery and the ultracapacitor are charged by regenerative power created across the load. Experiment results for a variety of scenarios are shown in figure 6 actions of a converter and in table 2.  For various scenarios involving the mobility of an electric vehicle, the following switching sequences have been derived from the above working principle of a four-port converter in table 2. Figure 3 Show the under different cases converter operations with switches.

░ 3. EVALUATION OF A PROPOSED MULTI INPUT CONVERTER: EFFICIENCY AND LOSS ANALYSIS
A theoretical study is performed for the converter, inverter, and converter with an inverter supplied induction motor to validate these simulation findings. For this evaluation, it is assumed that the simulation and theoretical implementation have the same parameters as: d1 (duty cycle of S1) = 70% d11 (duty cycle of S4) =50% d2 (duty cycle of S2) = 70% d22 (duty cycle of S5) =50% d3 (duty cycle of S3) =50% Vbatt=48 VPV= 35V Vu-c=60V (1) Case 1: VPV>Vbatt, Vc, Vo For this situation, VPV is input voltage is 35 volts. Table 3 displays the findings of a steady-state investigation of Vo, Vbatt, and Vu-c. This enhanced output allowed us to theoretically calculate the load voltage as Vo= 116.67 V.

CASES
Theoretical battery voltage and ultra-capacitor voltage were calculated using the buck result, which is Vbatt = d2Vpv; this gave us 25V. This means that SITO has three possible outputs: Vo = 116.67 V (boost), Vbatt = 25 V, and Vu-c=25V. (BUCK)

(2) Case 2: Vbatt>V u-c, Vo
In this scenario, the input voltage, Vbatt, is 48 V, and the values for Vo and Vu-c in Table 3 are derived from a steady-state study.
= (1 − 1 ) (Boosted results in load) (Boosted results in load). Theoretical load voltage was calculated to be 160 V given this data.
The theoretical value of the ultra-capacitor voltage was calculated to be 96 V using the boost result of This means that SIDO has two possible outputs, both of which involve Vo=160V. (BOOSTED) Vu-c= 96V (BOOSTED).

(3) Case 3: V u-c > Vbatt , Vo
In this scenario, the input voltage, Vbatt, is 48 volts, and the values for Vo and Vu-c in table 3 are derived from a steadystate study (boosted results in load). The theoretical load voltage was calculated, given this data, to be 160 V.
The theoretical value of the ultra-capacitor voltage was calculated to be 96V. Consequently, SIDO has two possible outputs: Vo = 160 V (boost) and Vu-c=96V. (BOOSTED).

Efficiency and Loss Analysis
The suggested multi-input bidirectional buck boost converter is much more efficient than a conventional buck boost converter with a positive output. It is possible to determine the efficiency shift of a multi-input bidirectional buck-boost converter under different operating conditions as follows: The efficiency of the converter is denoted by ∆η, and the efficiency of the proposed (multi-input bidirectional buck boost) converter is considered to be η 1 , where poutput is the output power, pinput is the input power, and pLoss is the power loss change.

Mode-1: (Boost and Buck)
Further switching components like a diode and a MOSFET in the conduction channel between PV and load provide the extra power loss in (33).

Mode-2: (Boost)
Between the battery and the ultra-capacitor, there are no extra switching parts, so the difference in losses can be calculated as ∆pLoss (Boost) = PS3 + PS2 PS1 is the power at the switch, and PS2 is the power at the shared switch connecting the load and the supply.

Mode-3: (Boost and Buck)
As no other components are involved in the conduction route between the loads and the battery, the variation in losses is the same as in Example Mode of Operation 2.

SIMULATION RESULTS OF THE PROPOSED MULTI-INPUT CONVERTER
The power flow to the load is provided by a multi-input bidirectional buck-boost converter, which is simulated with varying input power. In the dynamic instance of electric vehicles, this suggested converter is employed to provide different sources to meet the load requirement.
The effectiveness of the suggested system is assessed here. Taking into account the real irradiation parameter, this research employs a 9.6 kW PV module produced by the Soltech firm and designated 1STH-215-P. On display in Fig.1    When the BLDC Motor is required at night, the motor-run draws a full power only from the DC bus voltage. A peak sinusoidal supply current is drawn at UPF while regulating the DC bus voltage, Vdc at 381.8 V. The BLDC motor run attains its full speed at 2000 rpm. The various motor-pump indices refer to back emf (ea), stator current (isa), electromagnetic torque (Te), speed N, are shown in fig. 5.   Fig.6. Using Multi input converter to send the power to load, the study state power balanced The power flow to the load is provided by a multi-input bidirectional buck-boost converter, which is simulated with varying input power. In the dynamic instance of electric vehicles, this suggested converter is employed to provide different sources to meet the load requirement is show in fig.6.

░ 5. CONCLUSIONS
In this study, a Multi-input bidirectional buck-boost converter (MIB 3 C) is presented for hybrid and electric vehicle (HEV/EV) uses. The energy converter can process a wide range of inputs. Resources in one compact package, including photovoltaics, batteries, and ultra-capacitors. The complexity of the converter is decreased by the small number of components it uses, and it may provide a positive output voltage without a transformer. The converter can switch between many different modes, such as buck, boost, and buck-boost, and can handle electricity in both directions.
The continuous conduction mode (CCM) of the MIB3C has been investigated in both ideal and non-ideal situations. In addition, a PI controller is created to regulate the output voltage. To demonstrate the efficiency of the design, the converter's performance has been thoroughly evaluated over a range of operating circumstances.
MATLAB-Simulink is used for the extensive simulated research. In this analysis, the system's decreased size and weight in comparison to conventional hybrid energy storage systems is shown. Moreover, the battery's lifespan is lengthened and the ripple of output current is reduced.