JPH03261373A - Dc stabilized power supply - Google Patents

Abstract

PURPOSE:To suppress a ripple voltage by a method wherein the phases of the gate signals of the thyristors of respective units are made successively different and a DC power supply is apparently operated with a switching frequency in a multiple of the switching frequency of each unit. CONSTITUTION:Power is supplied by positive and negative DC power supplies 1 and 2 to a resonance type thyristor inverter circuit unit composed of thyristor elements 3, rectifiers 4, an inductor 5, a capacitor 6, a ratio frequency transformer 7 and rectifiers 8. The DC sides of the two units are connected to each other in parallel or in series and the phases of the modulation frequencies of the respective units are made to be successively different to multiply an apparent modulation frequency. Therefore, if a plurality of the DC power supply units are employed, a modulation frequency as a whole is a frequency in a multiple of each unit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to reduction of ripple voltage in a DC stabilized power supply using a resonant thyristor inverter.

(Prior Art) FIG. 1 is a circuit diagram of a conventional DC power supply using a resonant thyristor inverter, and FIG. 2 shows its operating waveform.

In FIG. 1, when a gate signal shown in FIG. 2 GIGm is applied from the positive and negative DC currents 1t1 and 2 through the thyristor element 3 and the rectifier 4 to each thyristor element, the result is shown in FIG.
1i, the current with the waveform shown in inductance 5. The voltage flows alternately through the capacitor 6 and the frequency transformer 7, generating a voltage as shown in FIG. 2e on the secondary side of the high frequency transformer. This voltage is exchanged to direct current using a full-wave rectifier circuit consisting of a rectifier 8.

A DC voltage E as shown in 211H is generated across the smoothing capacitor 9 and at its output end.

Part of this DC voltage is detected by voltage dividing resistor 10.11,
The amplified signal is transmitted to the differential amplifier 13 and compared with the reference voltage 12. The GIGz signal is fed back to the gate of the thyristor through the voltage-frequency conversion circuit 14 and the gate circuit 15, and the error with the reference voltage is frequency modulated, and the output voltage is The aim is to keep E constant.

(Problems to be Solved by the Invention) As mentioned above, the output voltage E includes the ripple voltage 1 shown in FIG. 2, and in order to reduce this ripple voltage,
Possible methods include increasing the size of the smoothing capacitor 9, adding a new filter circuit, or increasing the modulation frequency. However, if you increase the size of the capacitor,
Adding a filter increases the size of the power supply itself and makes it uneconomical. For this reason, it is most desirable to increase the modulation frequency, but there is a limit to the gate and off time of the thyristor element, and even a general-purpose type has a limit of 20
It is about kHz.

(Means for solving the problem) As described above, the present invention is aimed at reducing the ripple voltage of DC voltage using a resonant thyristor inverter system, and uses the DC power supply shown in Fig. 1 as one unit. The problem is solved by increasing the apparent modulation frequency by connecting a plurality of units in parallel or series on their DC sides and sequentially giving a phase difference to the modulation frequency of each unit.

(Function) As described above, when a plurality of DC power supply units are constructed, the overall modulation frequency becomes multiple times that of one unit, and the ripple voltage can also be reduced to one-fold. This is better than simply increasing the size of the smoothing capacitor or adding a filter circuit.

This also allows for a much smaller power source, which is economically advantageous.

(Example) An example according to the present invention will be described below based on FIGS. 3 and 4.

This example uses two resonant type thyristor inverter DC power supply circuits in one unit, and connects the DC side in parallel.
Give an example.

As explained with reference to FIG. 1, two units of thyristor elements 3.2 are supplied from positive and negative DC power supplies 1.2. Rectifier 4. Inductance 5. A resonant thyristor inverter circuit composed of a capacitor 6, a high frequency transformer 7, and a rectifier 8 is connected in parallel on the output DC side. In this case, the gate voltage of each thyristor element is set to
, as shown.

With that phase difference, the current 1i in each unit
The voltage waveforms on the secondary side of ixisL and high frequency are as shown in the figure. Therefore, the unit-synthesized DC output voltage E of each rectifier 8 has a waveform as shown in the figure.

The modulation frequency will be twice that of the waveform E in Figure 2 produced by the one-unit circuit in Figure 1, and the ripple voltage at Y will be halved if the smoothing capacitor 9 has the same capacity.

The stabilization method is to divide a part of the output voltage E into voltage dividing resistors10.11
The output of the differential amplifier 13 and the error amplifier circuit connected to the reference voltage is detected by the voltage-frequency conversion circuit 14 and the output gate voltage G of the gate circuits 15 and 16 having a phase difference from each other.
By transmitting tGxGsG4 to the gate of the thyristor element of each inverter circuit and modulating the number of switching waste waves, feedback is applied to stabilize the output.

Moreover, this method has the same effect even if the DC side of the output is connected in series.

In addition, the phase difference can be easily configured for gate circuits 15 and 16 by using flip, flop circuits, etc.

(Effects of the Invention) As explained above, the ripple Φ of the DC power supply can be reduced by using the resonant thyristor inverter method without increasing the capacity of the smoothing capacitor or adding a filter circuit by using multiple inverter circuit units.

Ripple voltage can be easily reduced by connecting them in series or parallel and creating a phase difference between their respective modulation frequencies.If the number of unit circuits is increased, the ripple voltage can be reduced in inverse proportion to the number of constituent units, and the effect is It has extremely high industrial and practical value.

[Brief explanation of drawings]

IF5 is a configuration diagram of a DC stabilized power supply circuit using a conventional resonant thyristor inverter, FIG. The figure shows a waveform diagram at each point to explain the operation of 1311. 1.2 DC power supply 3, thyristor element 4, rectifier 5, inductance 6, capacitor 7, high frequency transformer 8, rectifier 9, smoothing capacitors 10, 11 voltage dividing resistor 12, reference voltage 13, differential amplifier 14, voltage-frequency Conversion circuit 15, gate circuit G, G, G, thyristor gate voltage Llz18
14 Switching current e elaz Secondary voltage of high frequency transformer E Output voltage

Claims (1)

[Claims] A plurality of DC circuit units using resonant thyristor inverters are connected in series or in parallel, and their combined DC voltage is detected. In a stabilization method using thyristor switching frequency modulation, the thyristor gate signal of each unit is sequentially applied. A DC stabilized power supply that reduces ripple voltage by providing a phase difference and driving at a switching frequency that is apparently multiple times the switching frequency of one unit.