JPH01243849A - Method of controlling resonance converter - Google Patents

Abstract

PURPOSE:To prevent breakdown of elements and reduction of efficiency from the title converter, by detecting a set point arrival time of resonance capacitor voltage, by turning ON a semiconductor switch and by supplying energy to a drive circuit from a drive winding of a transformer. CONSTITUTION:A control device of a resonance capacitor is composed of a semiconductor switch 2 by FET, a transformer 3 having an input winding N1, an output winding N2 and a drive winding N3, a rectification-smoothing circuit 4, a starting circuit 6, a resonance voltage detection circuit 7, a peak current detection circuit 8, a drive circuit 9, an output voltage detection circuit 10, etc. By turning ON and OFF DC input supply voltage 1 with the semiconductor switch 2, the current is supplied to a load 5 through the output winding N2 of the transformer 3 and the rectification-smoothing circuit 4. At this time, when the voltage of a resonance capacitor C0 detects the set point arrival time, the abovementioned switch 2 is turned ON. When the output voltage gets to the set point then, it is forcibly turned OFF.

Description

[Detailed description of the invention] [Industrial application field] The DC input power supply voltage is turned on by a semiconductor switch.

Turn it off, obtain an alternating voltage at the output winding of the transformer that has a resonant circuit element, and use the rectifier and smoothing circuit to convert this alternating voltage! The present invention relates to a method of controlling a resonant converter in which a predetermined voltage is obtained by smoothing the current.

[Conventional technology]

In recent years, switching regulators are small and highly efficient, so they have been used as power supplies for communications equipment, general industrial equipment, etc.
Widely used. In particular, in power supplies for information terminals, there is a strong demand for smaller size, lower prices, and lower M-a, and single-circuit systems, GTT products, etc. are being actively developed.

However, as a result of many years of research and development, the square wave switching mode method that currently dominates switching regulators has almost been technically established.

Improvements in performance are increasingly dependent on the development of component parts.

Therefore, in a high frequency power amplification stage, an E class amplification circuit has been proposed in order to obtain high power efficiency. This is done by selecting the configuration and constants of the 71-C circuit so that the current i flowing through the 5-half-drop body switch and the voltage ■ applied to both ends of the lower barrel switch prevent 14 parties from existing at the same time. , the slope of both the initial rising value and the final falling value of the voltage waveform is set to zero.

However, in a switching regulator with input terminal fluctuations and load fluctuations, the above-mentioned E slow operation is the 7th, so the voltage is made zero when the current of the semiconductor switch rises and when it falls.

Historically, the critical point in the operation of this system is the point where the slope of the final voltage fall value becomes zero, and using this area is an economical design for the components. like this,
't'! A voltage resonant converter is used that performs a switching operation called resonant switching.

[Problem to be solved by the invention]

However, during transient fluctuations such as startup and load fluctuations,
With a voltage charged to the resonant capacitor connected in parallel to the semiconductor switch.

This may cause the semiconductor switch to turn on.

In this case, since the discharge current from the resonance capacitor flows through the trigger switch, the semiconductor switch may be destroyed or its efficiency may be reduced.

There was a problem with it being out of order.

[Means and actions to solve the problem]

In order to eliminate the above drawbacks, the present invention turns on and off the DC input power supply voltage using a semiconductor switch to obtain an AC voltage at the output winding of a transformer having a resonant circuit element, and converts this AC voltage into a rectifying and smoothing circuit. In the 7AOw method of a resonant converter in which a predetermined voltage is obtained by rectification and smoothing with Motion 4! III of a resonant converter characterized in that energy is supplied to a drive circuit from a line, and when the output voltage reaches a set value, the semiconductor switch is forcibly turned off by an AVR signal to obtain a constant voltage output.
! It provides a method for controlling

[Embodiment] FIGS. 1 and 2 are diagrams for explaining an embodiment of the present invention.

In Fig. 1, 1 is a DC input power supply, 2 is a semiconductor switch such as an FET, 3 is an input winding N1, an output winding Nt,
'a A transformer having a moving winding N.

4 is a rectifier consisting of a diode D1 and a capacitor CI.
5 is a load, and 6 is a starting circuit consisting of transistors Q1, Q2 and resistors R1 to R2.

7 is Transistoro 3. Resonant voltage detection circuit consisting of diode Dt, capacitor 02 and resistors Rh to R1, 8
are capacitor C3 and resistors R9 to R1! A peak current detection circuit 9 consists of transistors Q=, Qs, diodes D1. A drive circuit consisting of a capacitor C6 and resistors R11 to R1&, 10 is sg4 times 1I3IC, a capacitor C2 and a resistor R1? This is an output voltage detection circuit consisting of ~Rzz. Also, C6 is a resonance capacitor, Do is a clamp diode, and D< is a diode. 20. is a Zener diode, C,,C.

is a capacitor, and R2ff is a resistor.

The initial condition is the current of the resonance capacitor C++.

The operation will be explained with reference to FIG. 2, assuming that the voltage is zero and the voltage Vel of the capacitor C1 of the rectifier/smoothing circuit 4 is charged to the output voltage E. In this state, at current time t, a 1AO1 voltage V as shown in FIG. 2(e) is applied to the control pole of the semiconductor switch 2.

When the voltage is applied and the semiconductor switch 2 is turned on, as shown in FIG. 2(a), the electric current tli+2 flowing through the semiconductor switch 2, that is, the manually wound type m l M+ of the transformer 3 increases linearly over one hour. next.

Time! 1 [If you turn off the main conductor switch 2 at 2,
Voltage V of resonance capacitor C0. As shown in FIG. 2(b), the voltage E1 of the DC input power supply l and the transformer 3 are
The open inductance of the human-powered winding N1 gradually rises due to the current at 0 time t, ■. . -El, and the current te11 of the resonance capacitor C0 reaches its peak as shown in FIG. 2(C). After that, the electric current IE V C0 of the resonance capacitor c0 is the human power 'J of the transformer 3.
It continues to rise due to resonance with the open inductance L1 of tQ N + .

At time L4, VC6-El + (Nl/N2)
- Es, and the rectifier diode D+ of the rectifier and smoothing circuit 4 becomes conductive. As a result, the output winding N of transformer 3 becomes.

The output voltage E is clamped via the smoothing capacitor C1 of the rectifying and smoothing circuit 4, and the resonance capacitor C0
voltage v6. is a resonant waveform between the resonant capacitor C0 and the leakage inductance L of the transformer 3 that reaches a peak at time 2 t. The output winding current INK of the transformer 3 is, as shown in FIG. 2(d), the voltage VCO of the resonance capacitor C0 is again Vco=E+ + (Nl
/Nt) ・It rises until time t, when 'Es is reached.

Furthermore, the output winding current 2 of the transformer 3 continues to flow due to the energy occupied by the leakage inductance L2 of the transformer 3, and the output winding N8 of the transformer 3 becomes the output voltage E.
, the resonant capacitor C0 continues to be clamped to
voltage V,. Is it 9 o'clock t? The voltage E1 of the DC input power supply l is
However, the leakage inductance of transformer 3 is 1
-2, it continues to fall further after 3 hours, and becomes zero at 0 time t, when the clamp diode r]. becomes conductive, the clamp diode D0 takes over the current 1eo of the resonance capacitor C0, and the voltage of the resonance capacitor C0 becomes . is the clamp diode D. 9 forward drop voltage (-■, .). At the time, the output winding current of transformer 3 is IN! When becomes zero, 5 rectifier smoothing circuit 4
of! The current diode D becomes non-conductive, and the human-powered winding current 1□ of the transformer 3 rises linearly over an hour again at time t, as shown in FIG. 2(a).

Returns to zero at 0 or higher, operation IF]jlJl ends, and the same operation is repeated thereafter.In addition, if the semiconductor switch is FET
In this case, the clamp diode D can be replaced by a parasitic diode inside the FET. Furthermore, during high frequency operation, the resonance capacitor C0 can be replaced with the output capacitance of an FET.

By the way, in such a steady operating state.

The resonance voltage detection circuit 7 detects the voltage of the resonance capacitor C0. , and performs the above operation, but 2. For example, due to load fluctuations, the voltage vc0 of the resonant capacitor C0 does not drop to the set value of the resonant voltage detection circuit 7,
When the voltage is high, the diode D of the resonant voltage detection circuit 7 is reverse biased and the transistor Q is not turned on, but the fil1gM pole of the semiconductor switch 2 has a relatively high resistance resistor R? Since energy is supplied through the semiconductor switch 2, the semiconductor switch 2 gradually becomes conductive, and the voltage of the resonance capacitor C0 increases. gradually decreases. and.

When the voltage V11 of the resonant capacitor C0 reaches the set value, the transistor Q is turned on, short-circuiting the resistor R2, and rapidly turning on the semiconductor switch 2.

Current of semiconductor switch 2! , increases, one oscillation starts, and the state shifts to a steady state. In this way, if the steady state of operation is deviated from for some reason.

This can be detected by the resonance voltage detection circuit 7 and operated efficiently while being safely corrected. Further, at startup, the startup circuit 6 operates. At startup, energy is supplied to the control pole of the semiconductor switch 2 via the resistor R1, but the rL current input current I! If the voltage El at 91 is still low, there is a problem that normal oscillation cannot occur and the semiconductor switch 2 cannot be turned on completely, causing heat generation. In this embodiment, the transistor Q is kept on until the voltage E1 of the DC input power source 1 reaches a voltage at which the semiconductor switch 2 can operate, and when the voltage E1 of the DC input power source 1 reaches the voltage value, the transistor Q is turned on. , transistor Q, is turned off.

Since energy is supplied to the iL1ga electrode of the semiconductor switch 2 via the resistor R1, the semiconductor switch 2 does not generate heat. In this way.

When the voltage of the resonant capacitor C0 reaches the set value, the sixth drive circuit 9 will be described which, together with the operation of the resonant voltage detection circuit 7 described above, causes a transition to a steady operating state. A voltage obtained by combining the signal detected by the input terminal by the peak current detection circuit 8 and the signal detected by the output voltage detection circuit 10 by the capacitor C4 is applied to the base of the transistor Q5 and turned on. Transistor Q is turned on, and the semiconductor switch 2 is forcibly turned off at high speed by positive feedback. When the voltage generated in the drive winding N of the transformer 3 is reversed and the black dot side becomes negative, current flows through the transistors Q= and Qs through this negative voltage, and the transistor Q
4', Qs is forced to turn off at high speed. The zero-order peak current detection circuit 8 that can drive the semiconductor switch 2 at high speed in this manner will be described. The input current flowing through the resistor R is detected via the resistor R3, and the above AV
It is superimposed on the R signal. In this way, at startup and overload, the peak value of the input current is detected and set to 1, and voltage fluctuations of the DC input power source 1 can be corrected via the resistor R1.

[Effects of the Invention] As described above, the present invention provides an AC voltage to the output winding of a transformer that turns on and off the DC input power supply voltage I (by means of a conductor switch and connects 1 to 8 elements of the resonant circuit). tri+
In a side control method for a resonant converter in which a predetermined voltage is obtained by rectifying and smoothing this alternating voltage with a VFT circuit, the point in time when the voltage of the resonant capacitor reaches a set value is detected, and the semiconductor switch is turned on, energy is supplied from the drive winding of the transformer to the drive circuit, and when the output voltage reaches the set value, the AVR signal is sent to the 'I!' This is a method of controlling a resonant converter characterized by forcibly turning off a conductor switch to obtain a constant voltage output. Since the present invention has such characteristics, the semiconductor switch is not turned on rapidly while the resonance capacitor is charged with voltage, and damage to the semiconductor switch and reduction in efficiency can be prevented. . Furthermore, the semiconductor switch can be driven at high speed during steady state.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams for explaining one embodiment of the present invention. l...DC input power supply 2...' conductor switch 3...transformer 4...rectifier/smoothing circuit 5...load 6...starting circuit 7...resonant voltage detection circuit 8...・Peak current detection circuit 9...Drive circuit IO...Output voltage detection circuit C0...Resonance capacitor Do...Clamp diode Patent applicant Origin Electric Co., Ltd.

Claims (1)

[Claims] A DC input power supply voltage is turned on and off by a semiconductor switch to obtain an AC voltage at the output winding of a transformer having a resonant circuit element, and this AC voltage is rectified and smoothed by a rectifier/smoothing circuit. In a method of controlling a resonant converter to obtain a predetermined voltage, the point in time when the voltage of the resonant capacitor reaches a set value is detected, the semiconductor switch is turned on, and energy is transferred from the drive winding of the transformer to the drive circuit. Along with supplying
A method for controlling a resonant converter, characterized in that when the output voltage reaches a set value, the semiconductor switch is forcibly turned off by an AVR signal to obtain a constant voltage output.