JP3730525B2 - Multiphase rectifier - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for insulating and transferring a common control signal in a multiphase rectifier in which single-phase rectifiers of each phase are star-connected and each single-phase rectifier is controlled by a common control signal.
[0002]
[Prior art]
FIG. 5 is a block diagram of a multiphase rectifier to which the present invention is applied. It is possible to balance the input voltage of each single-phase rectifier by controlling the single-phase rectifiers 23, 24, and 25 with a common control signal. Is shown in
[0003]
FIG. 6 is a circuit diagram embodying the block diagram. This is a circuit diagram for circuit simulation. As a feature of the circuit simulator, since the main circuit and the control circuit can be handled as being insulated, the inputs of the multipliers 85, 86 and 87 are directly connected.
[0004]
However, considering the actual application, it is necessary to drive the switch elements 142, 143, and 144, and it is necessary to detect the output voltage, so the negative side of the output voltage is generally used as the reference voltage of the control circuit. Is. Commercially available control ICs are often built on that premise.
In that case, the reference potential of each phase control circuit is a different potential. Therefore, the multipliers 85, 86 and 87 cannot be directly connected, and some kind of insulation means is required.
[0005]
Signals input to the multipliers 85, 86, 87 are signals obtained by error amplification of the output voltage and the reference voltage and integrated, and are analog DC signals. This signal must be isolated and transferred, and the transferred signal must be common to each phase. However, it is not necessarily the same before and after transfer.
[0006]
FIG. 3 shows an example in which a photocoupler is used for insulation. If the resistance values of the resistors 20, 21, and 22 are the same and the current transfer rates of the photocouplers 16, 17, and 18 are the same, the voltages generated in the resistors 20, 21, and 22 are the same. This circuit has the merit of fewer parts, but it is difficult to arrange photocouplers with the same current transfer rate, for example, even if resistors 20, 21, and 22 can be adjusted as variable resistors and the deviation of current transfer rate is corrected Considering that the signals are not common due to the aging of the current transfer rate, it is difficult to adopt the disadvantages.
[0007]
FIG. 4 shows an example in which the influence of the current transfer rate is eliminated. An analog signal is converted into a digital signal by the A / D converter 200, the digital signal is transferred by the photocouplers 201 to 224, and the transferred digital signal is returned to the analog signal by the D / A converter 241. 4A shows a signal transmission circuit, and FIG. 4B shows a signal reception circuit. Although omitted in order to avoid complication, in practice, three sets of signal receiving circuits are necessary.
Since the information transmitted by the photocoupler is digital information indicating whether it is on or off, there is an advantage that there is no influence of the current transmission rate and there is no risk of deterioration over time.
However, even in this example, an A / D converter, a D / A converter, and a photocoupler for the number of bits that satisfy the required accuracy are required, and there is a disadvantage that the number of parts increases.
[0008]
[Problems to be solved by the invention]
The present invention isolates a common control signal in a multi-phase rectifier in which a single-phase rectifier input of each phase is star-connected, a converter is connected to each output, and each single-phase rectifier is controlled by a common control signal. It is to provide a simple means for transferring.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention of claim 1 is a multiphase in which single-phase rectifier inputs of each phase are star-connected, converters are connected to the outputs thereof, and the single-phase rectifiers are controlled by a common control signal. In the rectifier, each single-phase rectifier includes a triangular wave generator, a comparator that compares the common control signal and the output of the triangular wave generator, a photocoupler for each phase that is turned on and off by the output of the comparator, A smoothing circuit connected to the output of each photocoupler is provided. According to this configuration, the control signal to be transferred to each phase is compared with the triangular wave to create a pulse signal. Note that there is a correlation between the value of the control signal and the pulse width. For example, if the value of the control signal is large, the pulse width is widened, and if the value of the control signal is small, the pulse width is narrowed.
When the obtained pulse signal is transferred by a photocoupler and smoothed, a DC signal can be obtained. If a common pulse signal is input to the photocoupler of each phase and the smoothing circuit of each phase is made common, the obtained DC signal becomes common to each phase.
Since the photocoupler only transmits the on or off state, it is not affected by the current transfer rate.
[0010]
In order to solve the above-mentioned problem, the invention of claim 2 is a multiphase in which single-phase rectifier inputs of each phase are star-connected, converters are respectively connected to the outputs thereof, and the single-phase rectifiers are controlled by a common control signal. In the rectifier, each of the single-phase rectifiers includes a modulator that modulates the common control signal to convert it to an on / off signal, a photocoupler for each phase that is turned on / off by the output of the modulator, and a demodulator connected to the photocoupler. It is provided with. According to this configuration, the control signal is modulated and transferred to an on / off signal and demodulated by a common demodulator, so that the modulation method can be applied to other than PWM (pulse width modulation).
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 are diagrams showing an embodiment of the present invention. FIG. 1 is a block diagram and FIG. 2 is a circuit diagram. In FIG. 1 and FIG. 2, the same numbers are assigned to the same parts. . First, a control signal to be transferred to each phase is compared with a triangular wave to create a pulse signal. In this case, if the value of the control signal is large, the pulse width is widened, and if the value of the control signal is small, the pulse width is narrowed.
Transfer the pulse signal with a photocoupler. Since the diode sides of the photocouplers 1, 2, and 3 are connected in series, the same pulse current flows.
The transferred signal is smoothed by the smoothing circuits 7, 8 and 9. A specific circuit is shown in the smoothing circuit 9. Since the current cannot be sucked and discharged by the photocoupler, the operational amplifier 13 receives the pulse signal, generates the same pulse signal, and smoothes it by the resistor 14 and the capacitor 15. It is necessary to connect the input of the operational amplifier 13 so that the output of the operational amplifier 13 has the same polarity as the output of the comparator 5.
[0012]
【The invention's effect】
By using the present invention, it is possible to insulate and transfer a control signal with a small number of parts while eliminating the influence of aging of the photocoupler current transfer rate. By applying this to a multi-phase rectifier in which the single-phase rectifier input of each phase is star-connected and a converter is connected to the output of each phase, and each single-phase rectifier is controlled by a common control signal, the number of parts increases. It is possible to achieve the advantages of cost reduction and high reliability through restraint.
[Brief description of the drawings]
FIG. 1 shows an embodiment (block diagram) of the present invention.
FIG. 2 shows an embodiment (circuit diagram) of the present invention.
3 is a block diagram of a multiphase power supply apparatus to which the present invention is applied. FIG. 6 is a circuit diagram of a multiphase power supply apparatus to which the present invention is applied.
1, 2, 3: Photocoupler 4: Resistor 5: Comparator
6: Triangular wave generators 7, 8, 9: Smoothing circuits 10, 11, 12: Resistor 13: Operational amplifier 14: Resistor 15: Capacitors 16, 17, 18: Photocouplers 19, 20, 21, 22: Resistors 23, 24, 25 : Single-phase rectifiers 26, 27, 28: Converters 70, 71, 72: AC voltage sources 73, 74, 75: Ammeters 76, 77, 78: Voltmeters 79, 80, 81: Voltage detectors 82, 83, 84 : Absolute value circuits 85, 86, 87: multipliers 88, 89, 90: adders 91, 92, 93: integrators 94, 95, 96: voltage limiters 97, 98, 99: integrators 100, 101, 102: Adders 103, 104, 105: DC voltage sources 106, 107, 108: Triangular wave generators 109, 110, 111: Comparators 112, 113, 114: Full wave rectification Element 115, 116, 117: Inductor 118, 119, 120: Current detector 121, 122, 123: Rectifier element 124, 125, 126: Capacitor 127, 128, 129: Resistance 130, 131, 132: Voltmeter 133, 134 135: Voltage detectors 136, 137, 138: Capacitors 139, 140, 141: Drive elements 142, 143, 144: Switch elements 200: A / D converters 201-224: Photocouplers 225-240: Resistors 241: D / A converter

Claims (2)

In the multi-phase rectifier in which the single-phase rectifier input of each phase is star-connected, the converter is connected to the output of each phase, and each single-phase rectifier is controlled by a common control signal, each single-phase rectifier generates a triangular wave A comparator that compares the common control signal with the output of the triangular wave generator, a photocoupler for each phase that is turned on and off by the output of the comparator, and a smoothing circuit that is connected to the output of each of the photocouplers. A multiphase rectifier characterized by that. In the multi-phase rectifier in which the single-phase rectifier input of each phase is star-connected, the converter is connected to the output of each phase, and each single-phase rectifier is controlled by a common control signal, each single-phase rectifier is the common A multiphase rectifier comprising: a modulator that modulates a control signal and converts it into an on / off signal; a photocoupler for each phase that is turned on and off by an output of the modulator; and a demodulator connected to the photocoupler.

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