Low Speed Surface Aerator Controller

1. Available online at www.sciencedirect.com
ScienceDirect
Energy Procedia 00 (2017) 000–000
www.elsevier.com/locate/procedia
1876-6102 © 2017 The Authors. Published by Elsevier Ltd.
Peer-review under responsibility of the Organizing Committee of 2017 AEDCEE.
2017 International Conference on Alternative Energy in Developing Countries and Emerging Economies
Stand Alone Water Wheel Low Speed Surface Aerator Chaipattana RX-2-3,
Controller System
Snidvongs Suravut*1, 2
Jongjit Hirunlabh1
, Joseph Khedari2
, and Kunagone Kiddee1
1
Faculty of Engineering, Bangkok Thonburi University, Thailand.
2
Faculty of Technology and Innovation, Bangkok Thonburi University, Thailand.
Abstract
Water wheel low speed surface aerator Chaipattana Model RX-2-2 was the 9th patented aerator in the world. The patent was granted to the late king of
Thailand, King Bhumibol Adulyadej, with Patent No. 3127 February 2nd, 1993, Water wheel low speed surface aerator Chaipattana Model RX-2-2.
This model powered by induction motor 2 HP (1.5 kW) 380 VAC 50 Hz 1,450 RPM with warm gear and sprockets. Water wheel low speed surface
aerator Chaipattana Model RX-2-2 widely used in Kingdom of Thailand with standard aeration efficiencies (SAE) of 0.7-1.2 kgO2.kWh-1. However in
many instances it had no access to conventional power. Rural people could not afford for electical bills. Solar powered aeration would meet these
requirements, without a battery powered storage, lower power consumption, longer operation time, low cost, easy to operate, lighter, and easy to
transportation. The aim of this project was to develop a system that has lower power consumption, 0.25 HP (200 W) operate with solar power without
battery. It could operate at least 8 hours. Water wheel low speed surface aerator Chaipattana Model RX-2-3 was developed. This model is capable of
transferring oxygen at SAE up to 1.5-2.1 kgO2.kWh-1. This new design was developed a solar controller that match motor with solar cell for optimum
performance.
© 2017 The Authors. Published by Elsevier Ltd.
Peer-review under responsibility of the Organizing Committee of 2017 AEDCEE.
Keywords: Water Wheel Aerator, Solar Water Wheel Low Speed Surface Aerator .
1.Introduction
Normally water wheel low speed surface aerator Chaipattana Model RX-2-2 used 3 phase, 380V, 50Hz, 2HP (1,500W)
induction motor. To operate induction motor with solar cell is very hard as solar cell produce direct current voltage while
induction motor used alternating current. Standard solar cell voltage was 12, 24, 36, 48 Volts, direct current. To get 100, 220, 380
Volts, direct current, we must connect the solar cell in series. We must use inverter to convert direct current to altenating current.
Standard solar cell has power 60, 100, 200, 250, 300 W. To get 1,500 W we must connect the solar cell in parallel. To operate
solar cell with 1,500W induction motor 220V, 50Hz, 3 phases we must connect solar cell inserie and parallel. This is very hard to
match and find the solar cell size with induction motor. Until now it still not economy to run water wheel low speed surface
aerator Chaipattana Model RX-2-2 with solar cell.
In this research, Water wheel low speed surface aerator Chaipattana Model RX-2-3 used 1 phase, 100V, 150W, 10,000 RPM
universal motor with higher reduction gear ratio. Instead to connect solar cell in serie and parallel on this research we used single
solar cell, mono crystalline, 300 W, 36 Volts connected with DC-to-DC converter 150 W, 100 VDC, 1.5 A.
On real operation, we found that the solar cell voltage not at 36 VDC it could go up to 42 Volts. It damaged the power supply
of the controller system and also supplies voltage of DC-to-DC converters.

2. 2 Suravut Snidvongs/ Energy Procedia 00 (2017) 000–000
In this research, new supply voltage and control voltage of the controller system was redesigned. It could operate on input
voltage 100 VDC and supply regulated voltage 9 VDC 1 A.
The supply voltage, and control voltage of the power DC-to-DC converters by conventional linear methods has frequently be
based on linearization and state-space averaging model regarding an operating point to achieve a small-signal transfer function
which is around usable over a limit operating state[1]
. In the instance of boost configuration, the transfer function usually consist
at least one zero in the right half-plane (RHP)[1]
. Which the design for complicates controller. When the transfer function of
system rapidly varies through circuit operating situation, large-signal response cannot be certain construction the control system
design still less convenient. On the other hand, while a switched-method of DC-to-DC converter is able to a variable
configuration a sliding-mode control system approach for variable- systems can be utilized which provided the DC-to-DC
converter system exceeds large-signal immovability and strength to consideration variation.
In the paper, developed power DC-to-DC converter utilized through strategy of sliding-mode control, pulse width modulation
(PWM) is utilized to hysteresis control of variable-frequency current, so gives excellent dynamic performance in excess of a wide
input voltage range of 15 V to 55 V while transfer an output of approximately 100 V, 1.6 A. It also seen the of-harmonic instability to
occurs at duty ratios greater than 70%[2]
in traditional power DC-to-DC converters retain usual PWM fixed-frequency current-
control, which desire the further complexity of slope damages to resolution.
2.Methodology
Bidirectional boost half bridge converter model and Sliding Mode controller. Figure (1) show the half-bridge converter
topology is improved. The output voltage is controlled variable Vo and Vo* as the control reference voltage. VSO and Vst are DC
voltage sources and R as series resistance with the source Vst. Since, in the condition of a simplified load model, R represents the
internal series resistance and Vst as the internal voltage source which is dependent on SOC. This model and the following
investigation possibly will also be applied to a uni-directional converter with determine Vst to zero.
Figure (1) Shows Defining u and ū as the gate-drive logic position, the equations (1), and (2) describing this structure are as
follows:
_
LdiL = vso u – vou = u(vso + vo) - vo (1)
dt
_
C dvo = iLu – vo – vst = iL(1 – u) – vo - vso (2)
Dt R R
Figure 1. Bidirectional DC/DC half bridge buck/boost converter with sliding logic.
The output voltage control, a sliding defined logic in conditions of the variable controlled, Vo, and derived, dVo/dt are used in
[5]
is not practicable, while this imitative is discontinuous. as a substitute, a sliding surface, σ, is defined in terms error of output
voltage and current can be written as equation (3):
∆ voesr = ∆ lC rC = l Lmax rC (3)
3. Results and Discussion
To consider the systemic bidirectional DC/DC converter operation, a model was improved initially appropriate switching on a
low frequency of approximately 10 kHz. The operation of converter is optimized by dropping the hysteresis to increase the

3. Suravut Snidvongs/ Energy Procedia 00 (2017) 000–000 3
frequency switching and reduce the ripple current. The voltage source Vst in Figure (1) is a lithium ion battery by open-circuit of
20Vdc and the resistor R is set to 30 Ω for the principle of this proposed. Matlab/Simulink is utilized to model for the same
converter [5]
using components from the power Toolbox; in that case, the dynamic equations are utillize to form an average model of
the converter. The results are shown in Figure (2), and both the bursting order measured results and switching simulation can be
seen to confirm the averaged model, the predicted response of time constant is 6.2 x 10-4
s which is in excellent agreement by the
time constant of the measured response as shown in Figure (2(c)). An improvement to the average model possibly will be to
model the swing rate of the current of inductor current,
(a) (b)
Fig 2. a) Experimental setup b) Chaipattana Aerator Model RX-2-3 (c) Simulated switching response.
(c)
(d) (e)
Figure 3 d) Filter cut off frequency. e) Input voltage Vg = 5 Vdc (Yellow trace = Output Voltage 2 V / division. Cyan trace =
Inductor current 2 A / division).

4. 4 Suravut Snidvongs/ Energy Procedia 00 (2017) 000–000
Subsequently the cut off frequency filter is returned to the optimal value and bidirectional DC/DC the converter is
experimentation in various input voltage rates. At input voltage, 36V, the shape of the response can be seen to be reliable by the
response at the nominal input voltage, 36V. At 3 V the delay input voltage in the tracking of current error due to the swing rate of
the inductor starts to turn into significant and refer to the operation at this voltage rate the inductance should be decreased. Final
the converter response to change from step load 0.8Ω to 10Ω represents that from state of operation to the other effectively.
Subsequently the connection of power DC/DC boost converter in the total harmonic distortion on the current and output
voltage is less than bidirectional DC/DC converter. Table (1) shows the current in each case expending the phase voltage and
phase current. Comparison between input and output voltage of converter, torque, speed and efficiency under load condition are
shown in Table (1).
a) No Load b) Full Load
Figure 4 a) Comparison between input and output voltage of converter
With comparing the Power and efficiency in single unit and the speed improve and the efficiency as well. The current
reduced to be less than 4.5% for the current and the voltage. The power capability of the DC/DC boost converter system will be
greater through connecting the converter in bidirectional.
Table 1: Comparison between input and output voltage of converter, torque, speed and efficiency under load condition with
battery.
Full Load
Battery Converter V Converter Converter
Vin Vout Vin Vout Vin Vout Iin Iout Speed Torque Pin Pout n
V V V V V V A A r/min Nm W W %
1 24 23.83 30.21 27.02 0.850 0.590 232 0.175 20.25 17.82 88.00
2 24 23.83 40.14 36.82 1.183 0.608 398 0.198 28.19 24.40 86.55
3 24 23.23 50.00 46.68 1.583 0.613 545 0.214 36.77 30.65 83.35
4 24 23.02 60.30 56.83 1.934 0.613 685 0.226 44.52 36.96 83.01
5 24 22.84 70.62 66.48 2.222 0.603 811 0.235 52.75 42.62 80.79
6 24 22.77 80.19 76.07 2.650 0.595 947 0.245 60.34 47.71 79.06
4. Conclusion
A bidirectional DC/DC converter is utilized through current-control with sliding mode voltage strategy and limiting of input
and output current are improved. A straightforward and cost effective hardware realization using typical logic gates is
represented. A procedure for off frequency current filter selection has been obtain that provide the implementation of hardware
result to closely around to the theoretical in condition of a reduced arrange response previously the system refer to sliding mode.
The system reaction is shown comparatively robust and has a comparable form over a wide input voltage range circumstances.
The system composes of energy storage systems, power supply systems, Water wheel low speed surface aerator with energy
storage systems, Management system of battery charge and discharge and control circuits include variable voltage source is
interfaced to an additional. In the supercapacitor (SC) module which the voltage of SC can be maintain higher or lower than the
necessary output voltage, this converter configuration can be utilize to effectively charge and discharge of the SC and used to the
filled energy stored due to its wide input voltage range acceptance.

5. Suravut Snidvongs/ Energy Procedia 00 (2017) 000–000 5
Acknowledgements
This research was supported by the Bureau of the Royal Household, Chaipattana Foundation, Royal Irrigation Department,
and Bangkokthonburi University. We thank our colleagues from the Faculty of Engineering, Bangkok Thonburi University, and
Faculty of Technology and Innovation, Bangkok Thonburi University who provided warm encoragement to conduct this
research.
Special thanks to Mr. Panomkorn Thaisantisuk, Mechanical engineer specialist, Royal Irrigation Department for technical
assistance and useful comments.
We would also like to show our gratitude to Mr. Phol Polsen for his continous support during the course of this research.
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