International Journal of Applied Power Engineering (IJAPE)
This article presents the effect of supply voltage variations on single-phase capacitor-clamped m... more This article presents the effect of supply voltage variations on single-phase capacitor-clamped multilevel inverter-fed induction motor drives. This research is tailored at determining the best torque value and speed to attain a stable state under input voltage variation and minimum time response to realize low percentage harmonic distortions. The effect of constant power quality disturbance harms the performance and behavior of asynchronous motors based on harmonic contents and other energy source integrations. The multilevel inverter has shown good performance in motor drives. This paper deals with the effect of input voltage variations on a single-phase multilevel capacitor-clamped inverter for asynchronous induction motor drives. A five-level capacitor-clamped inverter with an in-phase disposition pulse width modulation technique is adopted. Four high-frequency triangular carrier signals are generated and compared with a reference sinusoidal signal. As a result of this approach,...
Bayero journal of Engineering and Technology, 2023
Distance protection schemes are used in the protection of transmission and distribution lines and... more Distance protection schemes are used in the protection of transmission and distribution lines and they use distance relay in their operations. The protection scheme is always partitioned into two or more zones and each zone is a certain percentage of the entire length of the line (which may also include the next line). With all things being equal, the tripping of the relays is solely a function of the zones where the fault occurred, that is, the location of the occurrence of the fault. However, it has been shown in this paper through simulations in Power System Computer-Aided Design (PSCAD) that for a LLG fault on the line (in Zone 1), the distance relay/protection system tripped inaccurately in Zone 2 for a fault impedance of 0.1Ω, 0.5Ω and 5Ω and trips accurately in Zone 1 for fault impedance of 1Ω, and 10Ω for the same type of fault and same location. Also, for a fault impedance of 0.1Ω, the system tripped at Zone 1 for LL and 3 phase faults and tripped in Zone 2 for LG and LLG faults for the same fault impedance and at the same location. This indicates that tripping zone in distance protection schemes are not solely dependent on fault locations but also slightly dependent on the fault impedance and type of fault.
1.0 Introduction In large grinding mills such as the mineral and cement industries where twin mot... more 1.0 Introduction In large grinding mills such as the mineral and cement industries where twin motor drives are used, the two major challenges which limit the use of two synchronous motors connected direct on line and mechanically coupled to the same mill are motor overheating – due to the fact that the two motors do not share the mill load equally, and the increased rate of wear of the gear teeth on the account of non alignment of the rotor positions of the two motors (Hoffmann and Trasky, 1972). The reason for these problems has been attributed to small inaccuracies in tolerances and manufacturing circumferential error, pitch diameter error, or rim face run out on the girth gear. Again, due to manufacturing tolerance or difference in wear, the girth gears do not mesh with the pinions exactly the same way, and so the rotors of the motors are not rotated at the same relative angular positions at the time of starting or during running (Valentine et al., 1977). A similar issue is small...
A single-phase nine-level inverter with a novel pulse width modulation (PWM) scheme for R-L load ... more A single-phase nine-level inverter with a novel pulse width modulation (PWM) scheme for R-L load is presented in this paper. Four triangular carrier signals that are identical to each other with an offset that is equivalent to the amplitude of the sinusoidal reference signal were used to generate the PWM signals. The inverter is capable of producing nine levels of output-voltage levels (Vdc, Vdc/4, Vdc/2, 3Vdc/4, 0,−Vdc,−Vdc/4,−Vdc/2, 3Vdc/4) from the dc supply voltage. In this paper the dc supply is obtained from ac supply which is boosted to a higher amplitude of dc voltage using dc to dc converter. In this paper, Matlab/ Simulink software is used for the system simulation. Hence, the output load voltage, current and FFT plots are obtained. This paper is focused on minimizing the number of semiconductors devices, weights, and costs for a higher number of output voltage levels. Index Terms: Boost converter, modulation index, multilevel inverter, pulse width-modulation (PWM), total ...
International Journal of Applied Power Engineering (IJAPE)
This article presents the effect of supply voltage variations on single-phase capacitor-clamped m... more This article presents the effect of supply voltage variations on single-phase capacitor-clamped multilevel inverter-fed induction motor drives. This research is tailored at determining the best torque value and speed to attain a stable state under input voltage variation and minimum time response to realize low percentage harmonic distortions. The effect of constant power quality disturbance harms the performance and behavior of asynchronous motors based on harmonic contents and other energy source integrations. The multilevel inverter has shown good performance in motor drives. This paper deals with the effect of input voltage variations on a single-phase multilevel capacitor-clamped inverter for asynchronous induction motor drives. A five-level capacitor-clamped inverter with an in-phase disposition pulse width modulation technique is adopted. Four high-frequency triangular carrier signals are generated and compared with a reference sinusoidal signal. As a result of this approach,...
Bayero journal of Engineering and Technology, 2023
Distance protection schemes are used in the protection of transmission and distribution lines and... more Distance protection schemes are used in the protection of transmission and distribution lines and they use distance relay in their operations. The protection scheme is always partitioned into two or more zones and each zone is a certain percentage of the entire length of the line (which may also include the next line). With all things being equal, the tripping of the relays is solely a function of the zones where the fault occurred, that is, the location of the occurrence of the fault. However, it has been shown in this paper through simulations in Power System Computer-Aided Design (PSCAD) that for a LLG fault on the line (in Zone 1), the distance relay/protection system tripped inaccurately in Zone 2 for a fault impedance of 0.1Ω, 0.5Ω and 5Ω and trips accurately in Zone 1 for fault impedance of 1Ω, and 10Ω for the same type of fault and same location. Also, for a fault impedance of 0.1Ω, the system tripped at Zone 1 for LL and 3 phase faults and tripped in Zone 2 for LG and LLG faults for the same fault impedance and at the same location. This indicates that tripping zone in distance protection schemes are not solely dependent on fault locations but also slightly dependent on the fault impedance and type of fault.
1.0 Introduction In large grinding mills such as the mineral and cement industries where twin mot... more 1.0 Introduction In large grinding mills such as the mineral and cement industries where twin motor drives are used, the two major challenges which limit the use of two synchronous motors connected direct on line and mechanically coupled to the same mill are motor overheating – due to the fact that the two motors do not share the mill load equally, and the increased rate of wear of the gear teeth on the account of non alignment of the rotor positions of the two motors (Hoffmann and Trasky, 1972). The reason for these problems has been attributed to small inaccuracies in tolerances and manufacturing circumferential error, pitch diameter error, or rim face run out on the girth gear. Again, due to manufacturing tolerance or difference in wear, the girth gears do not mesh with the pinions exactly the same way, and so the rotors of the motors are not rotated at the same relative angular positions at the time of starting or during running (Valentine et al., 1977). A similar issue is small...
A single-phase nine-level inverter with a novel pulse width modulation (PWM) scheme for R-L load ... more A single-phase nine-level inverter with a novel pulse width modulation (PWM) scheme for R-L load is presented in this paper. Four triangular carrier signals that are identical to each other with an offset that is equivalent to the amplitude of the sinusoidal reference signal were used to generate the PWM signals. The inverter is capable of producing nine levels of output-voltage levels (Vdc, Vdc/4, Vdc/2, 3Vdc/4, 0,−Vdc,−Vdc/4,−Vdc/2, 3Vdc/4) from the dc supply voltage. In this paper the dc supply is obtained from ac supply which is boosted to a higher amplitude of dc voltage using dc to dc converter. In this paper, Matlab/ Simulink software is used for the system simulation. Hence, the output load voltage, current and FFT plots are obtained. This paper is focused on minimizing the number of semiconductors devices, weights, and costs for a higher number of output voltage levels. Index Terms: Boost converter, modulation index, multilevel inverter, pulse width-modulation (PWM), total ...
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Papers by Gerald Diyoke