JPH01318545A - Dc stabilized power source using magnetic amplifier - Google Patents

Abstract

PURPOSE:To improve controllability by dividing the secondary winding into two parts and by connecting them from this branch point to a smoothing circuit through diodes. CONSTITUTION:An ON-ON type converter is equipped with a transformer T and switching elements Q1 to Q2 on its primary side. The secondary winding of the transformer T is divided into the let secondary winding n21 and the 2nd secondary winding n22, which are connected in series. The anode side of a diode D3 is connected to the anode side of this 1st secondary winding n21 through a saturable reactor SR and a diode D6 is connected to its center top. The cathode sides of diodes D3 and D6 are connected in common to the cathode side of a diode D4 and connected to a capacitor C2 through a choke coil L2. An error amplifier 10 outputs a signal relevant to the deviation of an output Vout. The output through transistors Q3 and Q4 is connected to a saturable reactor SR through a diode D5, whereby a route for resetting is formed.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a DC stabilized power supply using a mag-amp, and particularly to improvements in stabilizing the main output when using a mag-amp.

[Conventional technology]

A magamp is a magnetic amplifier, for example,
It is known that it can be used in a DC stabilized power source, such as in No.-160372. FIG. 6 is a block diagram of a DC stabilized power supply using a conventionally known mag-amp. In the figure, a DC voltage V is applied to the transformer primary winding nl, which is turned on and off by a switching element Q such as a transistor. Then, a switching signal appears in the main output secondary winding n2 of the transformer, which is connected to the diodes D1 and D.
2 is used for rectification, a choke coil L1 removes a high frequency component, and a capacitor C1 stores and smoothes the power to obtain the main output Vout1. The main output Vout1 is compared with a predetermined reference voltage Vref, and a signal that makes this difference zero is PWM fpulse width.
fat 1on) control signal is sent to switching element Q from the output stabilization circuit. A switching signal appears in the secondary winding n3 of the transformer, so this is connected to the diode 03. D4 is used for rectification, choke coil L2 is used to remove high frequency components, capacitor C2 is used to store and smooth electricity, and the projecting output V out2
I am getting . The sudden output V out2 is a predetermined reference voltage Vr.
ef, a signal such that the difference becomes zero is obtained by the mag-amp control section, and a diode D5 is connected to the saturable reactor SR installed between the anode side of the secondary winding n3 and the anode side of the diode D3. applied via. In such a configuration, the main output Vout1 is stabilized by PWM.
This is done through control, and since the stabilization of the sudden output VOut2 is performed using a mag-amp, the output voltage can be stabilized reliably.

[Problem to be solved by the invention]

FIG. 7 is an explanatory diagram when the output is stabilized only by the mag-amp. Generally, according to mag-amp control, P W M
Since output stabilization can be achieved at a lower cost than the 1-JilJ control, such a configuration is sometimes adopted to meet the demand for lower manufacturing costs. However, such a device has the following problems. Figure 8 is an explanatory diagram of an open loose switching power supply.
A) is a circuit diagram, and (B) is a waveform diagram showing the voltage ■D8 and current ■ acting on the switching element Q from above. , primary winding n1
A current 11 flows to the anode side of the coil, and a current 1 flows to the secondary winding n2. When switching element Q turns off,
Voltage V. 8 becomes a high voltage and becomes stable within a switching period (for example, 17 μsec), and in response to this, currents 11 and 11 are turned off. FIG. 9 is an explanatory diagram of an open-loose switching power supply equipped with a mag-amp, where (A) is a circuit diagram and (FB) is a waveform diagram. When switching element Q is turned off, voltage V. 8 becomes a high voltage and the switching period (for example, 17
It has an oscillatory response within 1 μsec). Then, the current I, 11 is not completely off, and a residual current flows, which has undesirable properties for control.The reason for this is that when the switching element Q is off, the mag-amp has a high impedance. As a result, the transformer winding becomes a high impedance state and cannot be reset. Therefore, the voltage v between the drain and source of the switching element
Ds is also unstable when turned off, and the Q (ratio of resistance to inductance) loss of the transformer becomes extremely large. The present invention has solved these problems, and aims to provide a DC stabilized power supply using a mag-amp that can reset the transformer and has less Q loss.

[Means to solve the problem]

The present invention that achieves these objects will be described. FIG. 1 is a configuration block diagram showing the concept of the present invention. In FIG. and. On the secondary side of the transformer, there is a secondary winding n2 in which this switched signal is induced, a saturable reactor connected to the anode side of this secondary winding n2, and the other end of this saturable reactor. The first diode D connected to the anode side
3, a second diode D4 in which the cathode side of the first diode D3 is connected to the cathode side and the cathode side of the secondary winding n2 is connected to the anode side, and this second diode D4 and a choke coil etc. A capacitor C2 is provided which is connected in parallel through the capacitor C2. Then, for output stabilization, a direct current using a mag-amp consisting of a control circuit that compares the output voltage of this capacitor with a predetermined reference voltage and sends a control signal to the saturable reactor in a direction where this error becomes zero. The stabilized power supply has the following configuration. That is, the secondary winding n2 is connected to the first secondary winding n21 and the second secondary winding n21.
a third secondary winding n22, the anode side of which is connected to the connection point between the first and second secondary windings n21 and n22, and the cathode side of which is connected to the cathode side of the second diode D3. This is characterized by the provision of a diode D6.

[Effect]

Each component of the present invention operates as follows. When the switching element is off and the saturable reactor enters a high impedance state, a path for resetting the secondary winding n2 is required. As this path, the secondary winding is divided into two parts n21,
22, and a third diode D6 is provided at this connection point.

【Example】

The present invention will be explained below using the drawings. FIG. 2 is a block diagram illustrating an embodiment of the present invention, in which an on-on converter is shown. The primary side of the transformer is a switching element Q1. It is a two stone type of Q2. In the case of a switching element, in the case of a transistor, the base terminal corresponds to the control terminal, the collector terminal corresponds to the input or output terminal, and the emitter terminal corresponds to the output or input terminal, and in the case of a FET, the gate, source, and drain correspond to each other. are doing. An input voltage Vtun is connected to the input terminal of the switching element Q1, a common is connected to the output terminal via the anode side of the primary winding n1 and a diode D8, and an on/off signal is input to the control terminal. The input terminal of the switching element Q2 is connected to the input voltage V rl via the cathode side of the primary winding n1 and the diode D7, the output terminal is directly connected to the common, and the control terminal is connected to the input voltage Vrl in synchronization with the control signal of the switching element Q1. The on/off signal is input. On the secondary side of the transformer, the secondary winding is divided into a first secondary winding n21 and a second secondary winding n22, which are connected in series. The anode side of the diode D3 is connected to the anode side of the first secondary winding n21 via the saturable reactor SR. The cathode side of the first secondary winding n21 and the anode side of the second secondary winding n22 are commonly connected and provided with a terminal called a center tap. The anode side of the diode D6 is connected to this center tap. And diode D3. The cathode side of D6 is commonly connected to the cathode side of diode D4, and
Connected to choke coil L2. second secondary winding n2
The cathode side of C2 is connected to the anode side of diode D4 and the common side of capacitor C2. The error amplifier 10 outputs Vout and a predetermined reference voltage Vr.
ef and outputs a signal related to the deviation, for example, a Zener diode or a differential amplifier is used. In the transistor Q3, the error signal from the error amplifier 10 is inputted to the base terminal via the resistor R2, and the emitter terminal is connected to the base terminal via the resistor R3 and to the common on the secondary side. The output Vout is connected to the terminal via a resistor R6, and serves as the operating output of the switch. In the transistor Q4, the base terminal is connected to the collector terminal of the transistor Q3 via a resistor R5, the emitter terminal is connected to the output Vout via a resistor R7, and the collector terminal is connected to a saturable reactor via a diode D5. It is connected. The operation of the device configured in this manner will be described next. Third
The figure is a waveform diagram of the device in Figure 2, where (^) is the voltage ■ acting on the switching element Q2. 8. (B) is the current I, (
C) is the current I flowing through the diode D3; (D) is the current I flowing through the diode D6. 6
In Figure 0, when the switching element Q2 is turned on, the voltage V. 8 becomes close to zero, and the current ■. is a flat predetermined value, and in response to this, the value of current (2) is determined, and current (206) generates a pulse signal with a shorter time width than that which occurs during a transient response. Next, when the switching element Q2 is turned off, the voltage VD
S increases for a while, but then the voltage gradually decreases and stabilizes at a value that is half of the input voltage V irL. The current ID is close to zero, and in response, the value of the current ■ also becomes zero. Fl! On the one hand, current I. 6 is zero when the voltage DS is more than half of the input voltage VfrL, but a current flows near that value, albeit at a meager value. FIG. 4 is an equivalent circuit diagram when switching elements Qi and Q2 are turned off at the same time. Switching element Q1. Q
When 2 is turned off, the saturable reactor becomes high impedance and the current ■D3 no longer flows. Therefore, the anode side of the first secondary winding n21 is equivalent to a disconnection state. However, even in this state, a conductive path is ensured by the diode D6, so the current ID6 flows. Therefore, it is possible to reset even when the transformer T is in the OFF state, and the voltage between the input and output terminals of the switching element Q2. 8 is also stable. FIG. 5 is a block diagram of the configuration of the present invention when the DC switching power supply is a so-called half bridge type converter. In FIG. 0, switching elements Q5. Q6 and capacitors cs and ce are connected in series, and the primary winding n1 is connected between these connection points.
installation is done. Switching element Q5. Q6 is turned on and off in a complementary manner. The secondary winding consists of two windings n3゜n4 installed symmetrically.
The 0 winding n3 is composed of the first winding n31 and the second winding n3.
winding n32, and a diode D is connected to this connection point.
63 is connected. Similarly, the winding n4 consists of a first winding n41 and a second winding n42, and a diode D64 is connected to this connection point. As a feature of the half-bridge type, the cathode sides of diodes D33, 34, 63, and 64 are attached at one point at the connection point of diode D4. The operation of the device configured in this manner will be described next. Switching element Q5. In response to the on/off of Q6, the secondary winding n3. A complementary switching signal is generated at n4. In this case, if a saturable reactor is used, the same problems as the on-on type will occur, so the secondary winding n on the side where the saturable reactor has high impedance 3. n
Diode D63.
Performed by D64.

【Effect of the invention】

As explained above, according to the present invention, the secondary winding is divided into two parts and the dividing point is connected to the smoothing circuit via the diode D6, so that the following effects can be obtained. . ■ Even when stabilizing the output voltage using only a saturable reactor, the transformer can be reset when the switching element is turned off, improving controllability. ■ Since residual vibration does not occur, the Q of the transformer can be small.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the concept of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention for an on-on converter, FIG. 3 is a waveform diagram of the device shown in FIG.
The figure is an equivalent circuit diagram when switching elements Q1 and Q2 are turned off at the same time, and FIG. 5 is a block diagram of the configuration of the present invention for a half-bridge converter. Figure 6 is a configuration block diagram of a DC stabilized power supply using a conventionally known mag-amp, Figure 7 is an explanatory diagram of output stabilization using only a mag-amp, and Figure 8 is an explanation of open loose switching power supplies. FIG. 9 is an explanatory diagram of an open-loose state of a switching power supply equipped with a mag-amp. nl...Primary winding, n21. n22...Secondary winding, SR゛(J', 1.',,' Figure 1 Figure 2 Figure J Figure 1 l j
Iru, Il l Figure 4 Figure 5 Figure L Figure 7 (A no V'n 1A) (A Tsum 6 Figure 673 Nodeko (B)

Claims (1)

[Claims] A primary winding to which a DC voltage is applied, a switching element that turns on and off the DC voltage of this primary winding, a secondary winding to which this switched signal is induced, and this secondary winding. a saturable reactor connected to the anode side of the line; a first diode with the other end of the saturable reactor connected to the anode side; and a cathode side of the first diode connected to the cathode side of the secondary winding. A second diode whose cathode side is connected to the anode side of the line, a capacitor connected in parallel with this second diode, and the output voltage of this capacitor and a predetermined reference voltage are compared to ensure that this error is zero. In a DC stabilized power supply using a mag-amp, the secondary winding is connected to a first secondary winding and a second secondary winding. and a third diode having an anode side connected to the connection point between the first and second secondary windings and a cathode side connected to the cathode side of the second diode. DC stabilized power supply using