Balancing Dynamic Load with Adaptive Power System for the DC Motor Control

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056
Volume: 04 Issue: 03 | Mar -2017 www.irjet.net p-ISSN: 2395-0072
© 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 2695
BALANCING DYNAMIC LOAD WITH ADAPTIVE POWER SYSTEM FOR
THE DC MOTOR CONTROL
1Mahamuni Mangesh Chandrakant, 2Prof. K Chandra Obula Reddy,
1ME,MSS College of Engineering and Tech,JalnaAffiliated to Dr.BAMU, Aurangabad, Maharashtra, India.
2Ass professor,MSS College of Engineering and Tech,JalnaAffiliated to Dr.BAMU, Aurangabad, Maharashtra, India.
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Abstract:A DC motor is any of a class of electricalmachines
that converts direct current electrical power into mechanical
power. A new Adaptive Power System (APS)isusedtomitigate
the negative impacts levied on the platforms resulting from
large dynamic loads is proposed in this paper. The Navy’s
future and near-term high-energy sensors and energy
weapons will consume a large portion of the resources of the
intended ship platform. The APS has used to maintain
generator/prime-mover reliability, and also it is used to
improve sensor/weapon performanceor improvemetricssuch
as system weight, cooling demands, and ship fueling costs.
Many of these new systems will have extreme dynamic power
profiles, including both periodic and aperiodiccharacteristics.
Here we are using dc motor because it has severaladvantages.
Such as, Speed control over a wide range both above and
below the rated speed High starting torque, Accurate steep
less speed with constant torque etc. The APS design is
presented along with simulation results verifying the concept.
By using the simulation results we can analyze the proposed
method.
1. INTRODUCTION
The APS is similar to the active filter concept whereby the
active filter provides the current needed to maintain the
quality of the load current required by the upstream power
system. Duty cycles can vary from small to continuous and,
for some cases, the peak power demands can be above the
capability of the ship power plant. A DC motor is any of a
class of rotary electrical machines that converts direct
current electrical power into mechanical power. The most
common types rely on the forces produced by magnetic
fields. Nearly all types of DC motors have some internal
mechanism, either electromechanical or electronic, to
periodically change the direction of current flow in part of
the motor. These types of extreme power profiles cannot be
supported with conventional power systems.
The Adaptive Power System (APS) concept presentedinthis
paper can be an enabling technology for sensorsorweapons
with large dynamic loads, which without the APS would be
incompatible with the upstream shipboard generator and
distribution bus. The APS consists of energy storage, a
bidirectional current source, and innovative control
techniques. Theseinnovativecontrol techniquesincreasethe
energy storage utilization, thus minimizing the energy
storage size. The linear behavior of the outer-energy loop
regulation technique the performance is maintained at all
operating conditions.
A block diagram of a conventional shipboard power system
is shown in the Figure 1. Conventional systems havefocused
heavily on providing well-regulated voltages and clean
power to the corresponding load. If the voltage dynamics
seen at the load are to be minimized, the output impedance
of each converter stage is minimized by using small series
inductance values, large shunt capacitance values, and
control loops with high bandwidths.However,toprevent the
mid to low frequency load dynamics this type of system is
presented from propagating back to thedistributionbusand
generator.
When compared with the passive filter method (brute-force
method) the APS can support the pulsed load at a fraction of
the size and weight needed. If using the active load method
without excessive power dissipation as would exist (throw-
away method), and for some specific applications without
timeline restrictions as would be needed if usinga refresh or
recharging type system (restricted-timeline method).
Fig. 1. A block diagram of a notional power system with the
APS attached
The time limit for the enhanced operation is limited
by the APS size, the size of the energy storage needed to
provide the delta power, and the maximum average power
allowed. This maximum allowed average power determines
the corresponding duty cycle of thisenhancedoperationand
hence the quickest allowed recharge time of the APS energy
storage. Consequently, a new approach is needed to manage
the load dynamics of emerging Navy systems Thenew
Adaptive Power System (APS) specifically addresses this
need. The APS can be used to efficiently mitigate bus
disturbances and reduce stress to the shipboard gensets by
converting the dynamic power load seen by the shipboard
power system into an equivalent rolling time average –

essentially serving as an active low pass filter to the
loaddynamics. As shown in Figure 1, the APScan beadded to
an existing system. The APS consists of energy storage, a
passive power filter, a bi-directional current source, and
innovative control loops, as shown in Figure 2.
Fig. 2. An overview of the functionality of the APS system.
The APS is similar to the active filter concept
whereby the active filter provides the current needed to
maintain the quality of the load current required by the
upstream power system. Active filters have been used for
years in alternating current (AC) power systems to reduce
the current harmonics and improve the power factor
presented to the source when the loads are nonlinear and
electrically noisy [10]–[12]. Induction motors ruled out all
the motors in industries in every application. But DC motors
were still used in certain applications where induction
motors cannot fulfill the need. so, dc motors have its own
significance in industries. This is because some special
characteristics they possess.Thebi-
directionalcurrentsourceefficientlydeliversthepulsedpowerd
emandfromtheAPSenergystoragetothedesiredsensororweap
onsystem,thus providing a buffer to the upstream power
equipment.
DC motors were the first type widely used, since
they could be powered from existing direct-current lighting
power distribution systems. A DC motor's speed can be
controlled over a wide range, using either a variable supply
voltage or by changing the strength of current in its field
windings. Small DC motors are used in tools, toys, and
appliances.
With the proper use of control loops and energy
storage, the APS can reduce the rate at which the power
demand on the generator changes, thus limiting the
dynamics and spectral content seen by the generator -
transforming a weapon or sensor system that hadotherwise
been incompatible with the platform’s power system into
one that is now feasible.
2. ADAPTIVE POWER S YSTEM (APS)
1.1.Overview
The goal of the APS is to minimize bus disturbances and
stress to prime-powerequipmentbyconvertingthedynamic
power load into an equivalent rolling average of the power
demand. The APS is designed to meet the proposed
requirement as shown in Figure 3.
Fig. 3. The power ripple filtering requirement of the APS
The APS implementation must also not interfere
with maintaining a stiff voltage (tightly regulatedvoltage)to
the load. The top-level components of the APS include the
energy storage capacitance and two control loops. One loop
controls the APS output current to provide the required
dynamic current to the load using the energy from the
storage capacitance, and the other loop maintains the
voltage across the energy storage capacitance to within the
allowed rating.
Figure 2 provides the detail voltage and current
waveforms for the APS as well as the generator power
waveform during the application of a dynamic load profile.
Operation of the Adaptive Power System is as follows:
• The current provided from the upstream power system is
regulated by the APS to be equal to the filtered (0.13 Hz)
current profile of the load demand. The compensation block
regulates Ibus to be equal to Iref by controlling the output
current of the bi-directional current source (BDCS); see the
bus-current and BDCS-current waveforms in Figure 2. The
BDCS is a DC/DC converter that can process power in both
directions – it can both absorb and deliver power.
• Hence, the AC component or dynamicsoftheloadprofileis
not part of Ibus but is provided by the energy-storage
capacitance via the BDCS.
• The energy-storage capacitance value is selected to be
large enough to provide the source and sink currents to
support the pulsed load demand. The value for the energy-
storage capacitance is minimized by allowing the voltage
across Cstore to vary significantly, where Udelivered = 1 2
Cstore(Vt20 − Vt2+), minimizing the energy storage
capacitance required. This provides significant weight and
size savings compared to using an in-linehigh-poweredlow-
pass filter (brute-force method).
– The voltage variation across Cstore is also decoupled from
the load, allowing tight regulation of the bus voltage seen by
the load to be maintained. Udeliveredistheenergydelivered
or absorbed by the storage capacitance, and Vt0 and Vt+ are
the corresponding voltages across the energy-storage
capacitance just prior to the load disturbance and after the

energy-storage capacitance has delivered or absorbed the
desired energy.
1.2.APS Requirements for Notional System
To demonstrate the APS functionality and
performance, a top-level designandsimulationfora notional
300-kW systemwas performed. For this specific system the
APS interfaces with the 375-VDC bus, as shown in Figure 1.
The system was designed to support the following load and
input–output performance specifications:
• Duty Cycle of Load: 0 to continuous
• Average Load Power: 0 to 300 kW
• Peak Load Power: 0 to 300 kW
• Input Voltage: 4160 VAC per MIL-STD-1399-680
• Input Interface Power Ripple Requirements: Figure 3
• Voltage Transients at the 375-V Bus Load Interface:
maintain to better than ±5%
1.3..APS Design Details for Notional System
Control Loop Bandwidth Considerations:
Figure 5 provides the schematic details for the APS.
The bi-directional current source is a modular design
consisting of thirty-eight 8-kW modules.
Fig. 5. The high-level schematic of an APS system used for
simulation, where N is the total number of parallel modules
(N=)38
The sizing and performance for the BDCS is based
on the bi-directional buck topology [17], using a 100-kHz
switching frequency and average current-modecontrol.The
switching frequency is chosen high enough to obtain the
needed control loop bandwidths (whichwill givethedesired
APS filtering performance) but low enough to maintain
acceptable switching losses. The inner current loop
bandwidth of the bi-directional current source is set to be
between 15 and 25 kHz (varies with the voltage across
Cstore), allowing the outer current loop of the APS to be set
at 4 kHz.
To simplify the analysis, the precedingassumptions
have been used, and therefore this signal flow graph is only
valid for low frequencies. In Figure 4, Ibus is the controlled
upstream bus current coming from the 375-V converter,
Iload is the current to the load before the 160-Hz filter, and
Gc is the transfer function of the 0.13-Hz filter, which has
been selected to be a secondorder filter defined as
(1)
where ω c is the corner frequency (in rad/s) and ζ is the
damping ratio. In this example, ζ is equal to 0.9. In addition,
Ku is the energy-loop gain that determines the energy outer
loop bandwidth, Kdroop is the gain of the energy droop
compensation (in J/A), Cact is the actual capacitance of
Cstore (in Farads), and Kc is the capacitance value (in
Farads) used in converting the measured capacitor bank
voltage, Vstore, to energy, the transfer function can
be determined as follows:
(2)
where N is the total number of forward paths, Pk is the gain
of the kth forward path, Δ is the determinant, and Δk is the
cofactor of path k. The gain of forward paths are defined as
(3)
(4)
(5)
where the bar over Vbus indicates a constant average value.
There is only one loop in Figure 4, which is defined as
(6)
The determinant is then
(7)
Because the loop, L, touches all the forward paths, the
cofactor for each forward path is simplify defined by
(8)
Fig. 6. The bus current filtering performance of the APS with
the proposed requirement overlaid (for example, a 100 kW
average load is allowed 3 kW peak ripple at 1 Hz). Because
the bus voltage is approximately constant, current filtering
directly relates to power filtering.
Figure 6 demonstrates that this equation’s
predictions (black dashed line) are nearly identical to the
detailed simulation results (solid blue line) up to 4 Hz, at
which point interactions with the current control-loop
compensator begins to appear.Figure 6 provides the time-
constant requirement via the frequency-domain
specification needed to determine the storage-capacitance
nominal value, Cdesign.
This results since K droop’s units are Joules/Ampere.
Knowing the amount of energy used,
(9)
along with the maximum available energy for use

(10)
the corresponding capacitance value can be solved for
(11)
Here, Iloadmax is the designed maximum load
current of the module, Vmax is the maximum allowed
capacitor voltage, Vmin is the minimum allowed capacitor
voltage.
Table I provides a summary of predicted component losses.
The MOSFETs used in the implementation of the BDCS are
silicon carbide devices. Silicon carbide devices are selected
because of the inherently low drain to source parasiti
capacitance, which is crucial to minimizing the switching
losses when operating at the high voltage levels with hard
switching.
TABLE I
POWERLOSSES OF THEAPS SYSTEM
2.PROPOSED REQUIREMENTS
The Navy’s MIL-STD-1399-680 addresses pulse loading
requirements, but only deals with pulses that occur
infrequently – less than once every 45 seconds [14]. A
requirement is needed that protects the genset and
distribution bus against the dynamics resulting from
frequent and repetitive pulsing loads but which is not as
restrictive as the present requirement of only allowing a
single pulse once every 45 seconds. Meeting the following
requirement would provide this protection,andwiththeuse
of the APS, this requirement is feasible to implement, even
for systems with large dynamic power profiles.
2.1.Proposed Pulsed Load Requirement:
The combined three-phase peak power ripple as
seen by the shipboard generator(s) at any single frequency
generated by the load shall be less than the limits defined by
Figure 3. The resulting allowed load profile proposed in
Figure 3 has been matched to the generator and prime
mover performance. Typical gensets’ response times to a
significant load change are on the order of 1.0 to 1.5sec[15],
[16]. If the rise and fall times for power changes (ramp rate)
seen by the generator are controlled to be slower than the
genset’s response times, the generator and prime-mover
control loops will be able to maintain the voltage and speed
regulation, bus disturbances will be kept to a minimum for
such a slow-changing power profile, and sub-synchronous
resonances will not be excited because the disturbances are
at lower frequencies
2.2. DC MOTOR
A DC motor is any of a class of electrical machines that
converts direct current electrical power into mechanical
power. The most common types rely on the forces produced
by magnetic fields. early all types of DC motors have some
internal mechanism, either electromechanical or electronic,
to periodically change the direction of current flowin part of
the motor. Most types produce rotary motion;a linearmotor
directly produces force and motion in a straight line.
A.Principle of DC Motor
This DC or direct current motor works on the principal,
when a current carrying conductor is placed in a magnetic
field, it experiences a torque and has a tendency to move.
This is known as motoring action. If the direction of current
in the wire is reversed, the direction of rotation also
reverses. When magnetic field and electricfieldinteractthey
produce a mechanical force, and based on that the working
principle of dc motor established.
Fig.7 block diagram of motor energy conversions
The direction of rotation of a this motorisgiven by Fleming’s
left hand rule, which states that if the index finger, middle
finger and thumb of your left hand are extended mutually
perpendicular to each other and if the index finger
represents the direction of magnetic field, middle finger
indicates the direction of current,thenthethumbrepresents
the direction in which force is experiencedbytheshaftof the
dc motor.
The input and output port variables of the direct current
motor are related by the parameter K.
(12)
B. Simulation results for Notional System
The DC/DC converter voltage control loop is set at
100 Hz. To demonstrate the effectiveness and benefitsof the
APS, Figures 9(a) and 9(b) provide simulation results for
various waveforms in the system when a dynamic load is
applied both with and without use of the APS.
The load profile chosen in Figures 9(a) and 9(b) not only
contains varying duty cycles but also simulates the extreme
stressing condition.

(a)Load and APS results.
(b)Generator results.
Fig. 9. Simulation results of the first load profile.
Figure 9(a) also shows thevoltagewaveformofthe
storage capacitor and the current waveform of the bi-
directional current source, demonstrating the APS’s
capability of providing the dynamic demand of the load
resulting in the generator only having to provide the rolling
average of the load power profile.
3. CONCLUSION
In this paper the Adaptive Power System (APS)
concept presented can be an enablingtechnologyforsensors
or weapons with large dynamic loads,whichwithouttheAPS
would be incompatible with the upstream shipboard
generator and distribution bus. APS has used to maintain
generator/prime-mover reliability, and also it is used to
improve sensor/weapon performance or improve metrics
such as system weight, cooling demands, and ship fueling
costs. The APS consists of energy storage, a bidirectional
current source, and innovative control techniques. A DC
motor is any of a class of rotary electrical machines that
converts direct current electrical power into mechanical
power. The APS design is presented along with simulation
results verifying the concept. By using the simulation results
we can analyze the proposed method. The most common
types rely on the forces produced by magnetic fields. These
innovative control techniques increase the energy storage
utilization, thus minimizing the energy storage size.The DC
motors were the first type widely used, since they could be
powered from existing direct-current lighting power
distribution systems.
ACKNOWLEDGEMENT
I would like to express my special thanks of gratitude to my
PG guide Prof.K Chandra Obula Reddy as well as our
principal sir Dr.S.K.Biradar sir of MSS College of Engineering
and Technology, Jalna. Who gave me the golden opportunity
to do this wonderful project. Which also helped me in doing
a lot of research and i come to know about so many new
things, i really thank ful to them. I sincerely thank to all my
faculty members of MSS College of Engineering and
Technology, Jalna for their continue encouragement and
active intrest in my progress that they give me throughout
the work.
REFERENCES
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of voltage/frequency modulation in ship electric networks
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BIOGRAPHIES
Mahamuni Mangesh Chandrakant
Completed B.E in Electrical &Electronics
Engineering in 2014 from /-DR.BAM
University, Aurangabad and PursuingM.Eform
MSS College of Engineering and
Tech,JalnaAffiliated to Dr.BAMU, Aurangabad,
Maharashtra, India. Area of interest includes Electrical
Power System.
Prof. K Chandra Obula Reddy
Working as Assistant professor in MSS College
of Engineering and Technology, Jalna. He
received his master's degree in power
electronic, from UTU university Belgaum, and his Bachelor's
degree in Electrical and Electronic engineering from JNTU
university Anantapur.

Balancing Dynamic Load with Adaptive Power System for the DC Motor Control

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