A system and method for reducing harmonics in a circuit is disclosed. The system comprises a main rectifier, ##EQU1## auxiliary rectifiers connected to the main rectifier, and an autotransformer connected to both the main rectifier and the auxiliary rectifiers which provides 2n-pulse rectification where n equals the number of phases of the system. The autotransformer generates ##EQU2## auxiliary voltage sets, each auxiliary voltage set having an auxiliary voltage amplitude, k, and an auxiliary voltage phase, .alpha., wherein ##EQU3## and wherein ##EQU4## assuming a main voltage amplitude of one and a main voltage phase of ninety degrees, wherein ##EQU5## and its integral multiples for all possible real values of k. The main rectifier has a main rectifier power rating, P.sub.mdb wherein ##EQU6## times the load power, and the auxiliary rectifiers each have an auxiliary power rating, P.sub.auxdb, wherein ##EQU7## times the load power.
The power supply interface (10) includes a rectification stage (18), having an autotransformer (40) connected to a power supply network (12), and a signal conditioning stage (20) having an output (28) supplying power to a load (14). The conditioning stage (20) includes a power module (22), for conditioning the power supply signal, and a control module (24) designed to control the power module (22). An autotransformer (40) includes at least one additional winding (62A, 62B, 62C; 64A, 64B, 64C) connected to the control module (24) to supply it with electrical power, the or each additional winding being magnetically coupled to at least one primary winding (44A, 44B, 44C) of the autotransformer (40). The power is supplied to a motor in an airplane.
In high-efficiency power source applications, AC power is converted to DC power, which is isolated from the source and regulated. A level of performance is achieved that exceeds the power quality requirements of MIL-STD-704 over the extended frequency range, typically from about 360 Hz to 800 Hz. While high-efficiency and low-weight of the invention, among other benefits, are advantageous primarily in airborne systems, its use can be extended to terrestrial applications as well. The isolation, regulation and the main power processing are achieved by low-weight, high-frequency conversion stages arranged in 2 channels that produce the line harmonic content typical of the 12-pulse rectification. Control of the conversion stages provides effective rejection of line transients, while output ripple voltage is typically an order of magnitude lower than in conventional transformer rectifier units.
A system and method for an autotransformer configuration including a plurality of windings which can be used to provide a substantial reduction in harmonics. The autotransformer includes a series of wye windings configured to provide a constant length voltage vector for any given input voltage, and a series of delta windings having a variable length voltage vector based upon turns ratio. The delta winding circuit is electrically coupled with the wye winding circuit to allow circulation of triplen harmonics, thereby reducing the effect on input current waveform such that total harmonic distortion (THD) is reduced, and producing an equivalent kVA rating that is lower than prior art applications, which results in savings in size, weight and cost.
Presented is a harmonic regulator that regulates a plurality of individual harmonics in a system having periodic torque disturbances to commanded values, including zero. For each harmonic being regulated, a feedback signal having at least one harmonic component due to the harmonic being regulated is transformed from a source reference frame to a harmonic reference frame of the harmonic being regulated to form a qd feedback signal. The qd feedback signal is subtracted from the commanded value to form a qd signal and regulated. The regulated qd signal is transformed to a destination reference frame to form a compensation signal and the compensation signal is added to a control signal to form a qd control signal that drives each harmonic being regulated towards the commanded value.
A synchronous motor controller and method of controlling a synchronous motor without using rotor position sensors are provided. In a floating synchronous reference frame controller, phase currents are measured and a current Park vector is determined. The error between an initially arbitrary floating reference frame is reduced with a control loop. Decoupling terms based on the estimated speed of the rotor and the stator winding inductance are used to generate decoupled voltage terms in the v- and u-axis of the floating synchronous reference frame. The decoupled voltage command is converted back to a stator reference frame and applied to the synchronous motor via a power electronic converter. As a result u-axis current is minimized during transients, and a robust and accurate estimation of the current vector to be used in coordinate transformation for controlling the machine are achieved and the need for overrating of motor and inverter components is avoided.
