A bleeder circuit for use in a power supply of a lighting system includes a first terminal to be coupled to a first input of the power supply. A second terminal is to be coupled to a second input of the power supply. An edge detection circuit is coupled between the first and second terminals of the bleeder circuit. The edge detection circuit is coupled to output an edge detection signal in response to an input signal between the first and second inputs. A variable current circuit is coupled to the edge detection circuit and coupled between the first and second terminals of the bleeder circuit. The variable current circuit is coupled to conduct a bleeder current between the first and second terminals of the bleeder circuit in response to the edge detection signal.

Bleeder circuit for use in a power supply

Integral cycle controllers (ICCs) are used for load power control. ICCs are switched at an integral number of cycles to effect this control. The load current for such controllers has an impact on the distribution supply bus: the impact occurs for low frequency (subsynchronous) phenomena and high frequency (supersynchronous) phenomena. Subsynchronous impact includes flicker on the distribution bus, and supersynchronous phenomena includes supply transformer core loss. The management of these power quality issues is discussed in terms of selecting the controller switching strategy. An innovative concept of group frequencies is discussed.

The impact of switching strategies on power quality for integral cycle controllers

A bleeder circuit for use in a power converter of a lighting system includes a current sense circuit coupled between first and second terminals of an input of a driver circuit to be coupled to drive a load. The current sense circuit is coupled to output a current sense signal in response to an input current through an input of the power converter coupled to the input of the driver circuit. An edge detection circuit is coupled between the first and second terminals to output an edge detection signal in response to an input signal between the first and second terminals. A variable current circuit is coupled between the first and second terminals to conduct a bleeder current between the first and second terminals in response to current sense signal and further in response to the edge detection signal.

Bleeder circuit having current sense with edge detection

Pulse-burst-modulated (PBM) loads cause line losses that are significant when compared with equivalent loads that are compensated to operate with sinusoidal line currents. This study details the conceptual design of a system meant to compensate the power factor of a load power conditioned by means of PBM. The compensator controller is a digital controller that monitors the line current and voltage and adjusts the compensation current accordingly. Simulations of the proposed method confirm the effectiveness of such a compensator maintaining a nearly sinusoidal line current, even in the presence of an inductive load.

A Digitally Controlled Unity Power Factor Compensator for Pulse-Burst-Modulated Loads

This paper presents a basic design concept and simulation of a 106 kVA high-power high-frequency (HPHF) power supply for feeding a transformer coupled symmetrical Cockcroft — Walton (CW) voltage multiplier producing 500 kV, 100 mA as the rated output for particle accelerators. Key technology includes high power converter with single-phase inverter that runs at 20 kHz and yields voltage of low THD and maximum dv/dt of 2 kV/ μs to prevent partial discharge in the transformer. The HPHF system is designed for varying the rated output voltage of 500 kV from 5% to 100 % of its value and to restrict the voltage rise time below 100 ms. At first, the Cockcroft-Walton circuit is simulated and its output parameters are obtained. Then, the simulation results of the designed HPHF system supplying the CW circuit has been presented and compared with design theory.

Design concept of a high power high frequency power supply for feeding 500 kV, 100 mA cockcroft-walton generator

This paper describes the measured harmonics in the load currents of thyristor circuits and shows that with firing
angle control the harmonic amplitudes decrease sharply with increasing harmonic frequency, but that they extend
to very high harmonic orders of around 6000. The amplitudes of the harmonics are a maximum for a firing delay
angle of around 90°.Integral cycle control produces only low order harmonics and sub-harmonics.It is also shown that with firing angle control apparently random inter-harmonic noise is present and that the
harmonics fall below this noise level at frequencies of approximately 250 KHz for a switched 50 Hz Waveform and
for the resistive load used. The noise amplitude decreases with increasing frequency and is a maximum with 90°
firing delay.

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N. C. Jones

Papers

Frequency spectrum generated by thyristor control