JPS5961476A - Power source - Google Patents

Abstract

PURPOSE:To obtain a DC voltage without using a rectifying and smoothing circuit by generating a 3-phase AC output by an inverter, and controlling the phase angle so that the voltage produced by adding or subtracting the instantaneous voltages of the phases becomes the desired value. CONSTITUTION:A clock generator 1 generates the operation clock of the sections of an inverter. A counter 2 generates an output at every pi/3 of the AC output generated from the inverter 2. A ring counter 3 sequentially generates the output of H level to the six output terminals by the output of the counter 2. 2/3 period PWM circuits 4, 5 generate pulses of the desired phase width. A delay circuit 6 temporarily stores the pulse width modulation waveform, and outputs the pulse width modulation waveforms in the phases corresponding to the six outputs in synchronization with the output timing of the ring counter 6. The 3-phase output is supplied through a buffer amplifier and an inverter to the output transformer drive circuit of the output circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device used, for example, in a corotron high voltage power supply of a copying machine.

For example, in a copying machine, a positive or negative high-voltage AC power supply or a high-voltage AC power supply is required for banding, transfer, first static elimination, and second static elimination, respectively.

In conventional copiers, each of these power supplies has 3 power supplies for each purpose.
~ 4 or two high frequency inverter devices for DC and AC were configured separately, and in order to form a DC power supply, these inverter devices were equipped with a rectifying and smoothing circuit. The power supply equipment was large and expensive.

The purpose of the present invention is to solve the above-mentioned problems in the conventional type.
In a power supply device, an inverter that generates a three-phase AC output is used.The idea is to sample each output at a period and pitch shorter than this AC output, and add and subtract these sampling values to obtain the desired output. Based on this, the purpose is to generate multiple outputs using one system of inverter devices and to obtain DC output without using a rectifying and smoothing circuit.

Hereinafter, the present invention will be explained in detail using drawings F.

FIG. 1 is a circuit diagram of a three-phase inverter control section of a power supply device according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a clock generator which generates operating clocks for each part of the inverter. The counter 2 divides the operating clock by Q' based on a signal from a reference number means such as a single-phase alternating current (not shown), and generates an output at π/3 of the alternating current output generated by the inverter.

The ring counter 3 generates +a level outputs at the six output terminals based on the output of the counter 2.
The /3 period PWM circuit 4.5 generates a /♀ pulse with a desired phase width. The delay circuit 6 temporarily stores the above-mentioned pulse width modulation waveform, and synchronizes with the output timing of the link counter 30 to connect each of these six outputs to the corresponding phase (U, V, W, U, V).

W) ni this/? Outputs a pulse width modulation waveform. FIG. 2 shows an example of the output waveform of each phase.

These three-phase outputs are supplied to output drive circuits 13, 14 and 15 of the output circuit in FIG.
As a result, each primary winding of the output transformer 16 is 2π/3
This output transformer 16 is driven by signals with different phases.
A high-voltage three-phase AC output as shown in FIG. 4 is generated from each secondary winding.

FIG. 5 shows a switching circuit according to one embodiment of the invention. In the same figure, each switch SW 1 to SW 7 is, for example, a photocoupler including a photothyristor and a light emitting element connected in antiparallel, and is controlled on/off by a tie-in/-can control circuit (not shown), and each winding can be used alone or Each winding is connected in 11 direct or reverse phase 11 rows. The table shows the relationship between on/off of each switch and output voltage.

Note) 1 indicates on.

Incidentally, when the U-phase output is expressed as E□5in (θ-30°), θ indicates the central angle of the sampling phase for obtaining the DC output voltage go'. The sampling width can be set on both sides of this central angle within the range allowed by the precision of the DC voltage. This sampling width may be variable, for example, depending on the output or samples.

Is it possible to select only the maximum output of the AC output as shown in the two series with a three-phase half-wave rectifier circuit? (sampling width 6Cf') output can be obtained. The direct light output voltage can also be set to any value of -EQ-EQ.

Note that by increasing the number of switches and performing reverse phase connections, for example, by making connections such as UV, TJ-W, [J±v+w, etc., the output voltage is -2E, ~2E.

In addition to making it possible to set the voltage within a range of If used, an extremely smooth direct current flow can be obtained without using a smoothing capacitor. For example, the voltage E mentioned above. When obtaining a rectified output of , the maximum number of samplings of one cycle of light is 24 (assuming they do not overlap). This sampling center angle is, for example, 3 r 16' (U
-V).

95'16' (U-W), etc., if you set it so that the addition/subtraction value of the instantaneous value becomes the planer output voltage.

As described above, according to the present invention, three
The l- To achieve this, a rectifier and smoothing circuit is used.
・It is possible to obtain a direct current voltage and a voltage with a desired waveform without any trouble, and it is also possible to generate multiple types of outputs simultaneously with one device. Therefore, it is possible to reduce the size and cost of the device.

In addition, if AC output is required for secondary static elimination etc., please use U.
, V or W output can also be used as is.

[Brief explanation of drawings]

11ZI is a block diagram of the control section of the imper and inverter according to one embodiment of the present invention, FIG. 2 is a diagram of each control output waveform of the circuit of FIG. 1, and FIG. B) Circuit 1 of the output circuit of the inverter, FIG. 4 is an output waveform diagram of the circuit of FIG. 3, and FIG. 5 is a circuit diagram showing a switching circuit according to an embodiment of the present invention. 16 Output Lance, swi~7 ・Switch. Patent applicant: Toshiba Electric Power Co., Ltd. Agent: Patent attorney Tatsuo Ito a) Tetsuya Tsuka Figure 2 Figure 3 U v UW Figure 4 Figure 5

Claims (1)

[Claims] an inverter that includes a three-phase output transformer having three output windings and generates a three-phase AC output through the output transformer; a first switch group which is controlled to be on/off and connects one to three of the output windings in series in the same phase or opposite phase for each time pitch; and a first switch group connected directly or to the terminals of the output windings. A power supply device comprising: a second switch group that connects a load via any of the constituent switches.