a novel power management control strategy for renewable energy power system

8/8/2019 A Novel Power Management Control Strategy for Renewable Energy Power System

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A Novel Power Management Control Strategy for

Renewable Energy Power System

CONVENTIONAL TOPOLOGY:

To The PV power system can be classified into two types:

stand-alone PV system and grid-connected PV system. In

remote or isolated regions where power grid can not extend to,

stand-alone PV schemes have found a fairly wide application to

meet the need for small but essential electric load. The output

power of the solar cell is changed by environmental factors,

such as irradiation and temperature.

Therefore, an auxiliary energy source such as a battery must be

introduced into the PV system as an energy buffer to balance

the input power from the solar cell and the output power to the

load.

In traditional stand-alone PV system, the battery is directly in

parallel with the DC Bus, and its charge and discharge current

cannot be controlled. Once the load changes significantly, the

rush current would destroy the battery.


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Therefore, a bi-directional converter needs to be inserted

between the DC Bus and the battery to control the charging and

discharging current.

PROPOSED TOPOLOGY:

The proposed stand-alone Grid connected renewable energy

power system is composed of a solar cell array, a battery, a uni-

directional DC-DC converter (UDC), and a bi-directional DC-

DC converter (BDC) and inverter. The solar cell array and

battery are connected to the same DC Bus through the high

conversion ratio DC-DC converter and Buck/Boost bi-

directional converter, respectively.

Abstract:

The solar photovoltaic power has received great attention and experienced

impressive progress in the countries all over the world in recent years

because of more and more serious energy crisis and environmental pollution.

This project proposes a novel power management control strategy for

stand-alone photovoltaic power system, which consists of a solar cell array,

a battery, a uni-directional DC-DC converter, and a bi-directional DC-DC

converter. The solar cell array powers the steady state energy and the battery

compensates the dynamic energy. The goal of the power management


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control strategy is to control the un-directional DC-DC converter and

bi-direction DC-DC converter to operate in suitable modes according to the

condition of solar cell and battery, so as to coordinate the two sources of

solar cell and battery supplying power and ensure the system operates with

high efficiency and behaviors with good dynamic performance. A

experimental prototype of stand-alone photovoltaic power system was built

and Experimental results are shown to verify the effectiveness of the

proposed power management strategy.

ADVANTAGES OF THE PROPOSED SYSTEM:

The system has several advantages:

(1) The charging and discharging currents of the battery are

only controlled by the BDC, and the system structure is

simpler;

(2) The over-load power is supplied by the battery, thus the

power rating of the solar cell array is selected to meet the

system power rating, leading to a reduced system cost;

(3) The power management can be realized through the

control of the UDC and BDC, ensuring the system to

work with high efficiency.


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APPLICATIONS OF PROPOSED TOPLOGY:

1. Solar cell feeding various power supplies, portable equipments

applications.

2. Utility interfacing converter

Fig: Stand-alone PV system


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FIG: FUNCTIONAL BLOCK DIAGRAM OF PROPOSED NOVEL

POWER MANAGEMENT CONTROL STRATEGY FOR PHOTO

VOTOIC POWER CONDITIONING SYSTEM


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PROPOSED DC_DC CONVERTER TOPOLOGY USED FOR SOLAR

CELL INTERFACING:

In this project, a novel high capacity grid-connected PV system based on Boost2

Buck converter +dual-level four-leg inverter is proposed, which not only allows a wide

range of input voltage, but also is able to compensate unbalance current of the local load.

Both of PV grid-connected generation and active filtering need to keep DC bus stable and

the key of unified control is generating the uniform current reference accurately. This

project explains the control algorithm of each power stage and the unified control

strategy for combination of two functions in detail. In addition, the unified control

strategy can suppress circulating current of dual-level inverter efficiently. Then the

system equivalent model is analyzed to indicate stability of the unified control.


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Fig: Transformer less DcDC High step-up converter used for

Renewable sources interfacing

a novel power management control strategy for renewable energy power system

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