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Synchronous machines
Published in Sergey E. Lyshevski, and Applied Mechatronics, 2018
Conventional permanent-magnet stepper motors have unifilar or bifilar winding configurations. For an unifilar winding configuration, as shown in Figure 7.39a, one has two phases and four lead wires. Hence, bidirectional phase voltages uas and ubs should be supplied to the as and bs windings. That is, to drive a stepper motor, positive and negative voltages must be applied to the phase windings. This increases the complexity of power converters (the so-called servo-drivers or power amplifiers); the bifilar winding configuration is a preferable choice in many applications. Here, each phase winding has a pair of windings, and four-phase stepper motors have six or eight lead wires connected to the voltage- or current-fed converters (see Figures 7.39b and 7.39c). Unipolar and bipolar servo-drivers are predominantly used. Permanent-magnet stepper motors with bifilar windings can be considered as four-phase devices. However, magnetically, they are two-phase devices.
B
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
bidirectional bus bidirectional bus a bus that may carry information in either direction but not in both simultaneously. bi-directional laser a ring laser with both clockwise and counter-clockwise circulating waves. Useful as a rotation rate sensor. bidirectional pattern a microphone pickup pattern resembling a figure eight, in which the device is most sensitive to sounds on either side of the pickup element. bi-directional resonator a standing-wave resonator or a ring-resonator in which the electromagnetic waves circulate in both the clockwise and counteclockwise directions. bidirectional transducer a surface acoustic wave (SAW) transducer which launches energy from both acoustic ports which are located at either end of the transducer structure. bidirectional transmission distribution function (BTDF) the optical scattering function for transmissive optics. The scattering function vs. angle is normalized to signal at zero degrees and with respect to solid angle of detector, including obliquity factor. bifilar winding a two-wire winding. It is often utilized in stepper motors to permit a unipolar power supply to produce alternating magnetic poles by energizing only half of the bifilar winding at any one time. bifurcation a term from Chaos Theory referring to a sudden change in the qualitative behavior of the solutions. bifurcation diagram a diagram where the sampled variable is plotted versus a parameter. The sampling period is equal to the source period. Similar to a Poincar' map. e big endian a storage scheme in which the most significant unit of data or an address is stored at the lowest memory address. For example, in a 32-bit, or four-byte word in memory, the most significant byte would be assigned address i, and the subsequent bytes would be assigned the addresses: i + 1, i + 2, and i + 3. Thus, the least significant byte would have the highest address of i + 3 in a computer implementing the big endian address assignment. "Big endian" computers include IBM 360, MIPS R2000, Motorola M68000, SPARC, and their successors. The little endian approach stores the least significant unit at the lowest address. (The terms big endian and little endian are taken from Jonathan Swift's satirical story, Gulliver's Travels.) See also little endian. BIL See basic lightning impulse level and basic impulse insulation level. bilateral Z-transform form
A High Efficiency Modified Forward Converter for Solar Photovoltaic Applications
Published in Electric Power Components and Systems, 2023
Praveen V. Pol, Sanjaykumar L. Patil
As the proposed forward converter is modified for simplification, the losses due to the components and gets eliminated, but the losses due to the leakage inductance of the primary with respect to tertiary winding exist since the energy stored in cannot be recovered [19]. This problem is overcome by using a new mixed-stranded transformer winding technique which is proposed in this paper. This technique is more effective in reducing the leakage inductance as compared to the bifilar winding technique. The losses due to the leakage inductance become negligible and hence, the equivalent circuit shown in Figure 6, can be represented without any primary leakage inductance.
Improved Trans-Z-source inverter based dynamic voltage restorer
Published in Australian Journal of Electrical and Electronics Engineering, 2022
The proposed inverter topology shown in Figure 2 which comprises a fast recovery diode, with minimal reactive components of having only one high frequency transformer and one capacitance thereby the system efficiency increases. The transformer is made up of 2 bifilar windings intentionally made with high precision to have tighter coupling and hence to have zero leakage inductance. Also the parasitic capacitance present in the tightly coupled bifilar winding lowers the rate of change of input voltage variations and could facilitate the effective boost ratio inheriting all the parental characters of Z source topology. The wide voltage boost gain is achieved by selecting the turns ratio greater than one.