JPS6349110Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to reducing the capacitance of a hunting prevention capacitor in parallel redundant operation of a converter.

Multiple converters are connected in parallel so that even if one of them fails, the remaining converters will continue steady operation.
Parallel redundant operation methods are being used in power supplies for computers and other devices in an attempt to improve system reliability. By the way, the parallel operation of converters is, for example, as shown in the circuit diagram shown in Figure 1, in which three converters CON ₁ , CON ₂ , and CON ₃ with the same configuration are each operated with a backflow prevention function to prevent inflow from the other converter. (OR) are connected in parallel to the load L via diodes D ₁ , D ₂ , and D ₃ . and the terminal of load L
Wiring for remote sensing of the voltage of L ₁ and L ₂ , that is, the load voltage rs ₁ , rs ₂ , remote sensing terminal
Detected by voltage tracking circuit 1 via Rs ₁ and Rs ₂ ,
Through this control of the reference voltage setting value of the constant voltage control circuit 2, the output voltage of the converter main body 3 at the output terminals O ₁ and O ₂ is controlled in accordance with the load voltage, and power is supplied. . In Figure 1, T _r is a transistor for voltage tracking control, R ₁ , R ₂ and VR ₁ are voltage dividing resistors for load voltage detection, E _S1 is a reference voltage source, AMP is a voltage comparator amplifier, and 4 is an overvoltage detection circuit, R ₃ , R ₄ and VR ₂ are voltage dividing resistors for overvoltage detection, E _S2 is a reference voltage source,
COP is a voltage comparison circuit. However, in parallel operation of converters, when the distance between the output terminal and the load becomes long, and the length of the output wiring OS ₁ , OS ₂ and the remote sensing wiring RS ₁ , RS ₂ becomes long, hunting occurs and the parallel operation is interrupted. You will be unable to drive. That is, in principle, the output voltage of the converter includes not only a direct current component but also a large amount of an alternating current component, and the higher the drive frequency of the converter, the higher the frequency of the alternating current component. For this reason, when the converter device operated in parallel and the load are separated, the output wiring OS ₁ through which a large load current 4 (for example, 50 A) flows,
Due to the impedance of OS ₂₂ , for example, the AC output voltage of output terminals O ₁ and O ₂ is
The AC load voltages at L ₁ and L ₂ will have a phase lag. On the other hand, the current flowing through the remote sensing wires RS ₁ and RS ₂ is extremely small and causes almost no phase delay, so the output terminals of the remote sensing terminals RS ₁ and RS ₂ are
The load voltage whose phase is delayed from the voltage at O ₁ and O ₂ is directly detected. Therefore, a converter having a voltage tracking circuit 1 and a constant voltage control circuit 2 controlled by this detected voltage cannot operate stably due to control hunting.

Therefore, in order to prevent this, conventionally the first
As shown in the figure, phase compensation capacitors C ₀₁ and C with extremely low impedance for AC components are installed between the output terminal O ₁ and the remote sensing terminal RS ₁ and between the output terminal O ₂ and the remote sensing terminal RS ₂ , respectively. ₀₂ is connected to stop the DC component, while for the AC component, the phases are forced to match by shorting between terminals O ₁ and RS ₁ and between terminals O ₂ and RS ₂ . However, this method has drawbacks as explained below.

First, in order to match the phases without causing hunting, the phase compensation capacitor C ₀₁ ,
As C ₀₂ requires a large capacity,
The distance between the converter and the load is limited by the capacitance value. The second problem is failure to start the converter at the start of parallel operation. That is, when starting a converter device that has stopped supplying power by stopping the converter main body 3 among a plurality of converter devices connected in parallel, the phase compensation capacitor of this later converter device
C ₀₁ is the second
The battery is charged with the polarity shown in the figure by the load voltage by the charging circuit indicated by the arrow in the partial circuit diagram of the figure. Therefore, when the converter main body 3 is started, the base of the transistor Tr of the voltage tracking circuit 1 and the voltage dividing resistors R ₃ , R ₄ , VR ₂ of the overvoltage detection circuit 4
A voltage V, which is the sum of the load voltage and the charging voltage of the phase compensation capacitor C ₀₁ , is applied to . As a result, the voltage tracking circuit 1 changes the potential of the reference voltage terminal of the voltage comparison amplifier AMP of the constant voltage control circuit 2,
It controls the output voltage of the converter main body 3 to match the voltage V, and works to abnormally increase the output voltage. When the voltage applied to the overvoltage detection circuit 4 exceeds the reference setting voltage E _S2 , the operation of the converter main body 3 is stopped, resulting in a startup failure. The purpose of the present invention is to provide a converter device that can eliminate phase delay and prevent hunting by using a phase compensation capacitor with a small capacity without causing the above-mentioned drawbacks. The details will be explained using

FIG. 3 is a circuit diagram showing an embodiment of the present invention, and its features are as follows. That is, in the conventional circuit described above with reference to FIG. 1, the RS ₁ side end of the phase compensation capacitor C ₀₁ connected between the output terminal O ₁ and the remote sensing terminal RS ₁ is disconnected, and this is connected to the constant voltage control circuit. The intermediate point of the two voltage dividing resistors for detecting the load voltage, for example, constitutes the resistor _R1 .
Connect to the connection point of dividing resistors R ₁₁ and R ₁₂ with an appropriate resistance ratio to connect P in the voltage dividing resistor circuit for load voltage detection.
The voltage phase of the alternating current component at the point is made to match that of the output terminal _O1 . Note that the phase compensation capacitor C ₀₂ is connected to the output terminal O ₂ and the remote sensing terminal RS ₂ .

If this is done, the resistance of the voltage dividing resistor circuit for detecting _the load voltage _will be large, and the flowing current will be extremely small. Also, the phase of the AC voltage applied to the constant voltage control circuit 2 can be made to match that at the output terminal _O1 .

According to experiments, the drive frequency is 100KHz and the output rating is
Wiring for output power in 5V, 50A converter
When the lengths of O ₁ and O ₂ are each 6 m and a total of 12 m,
In the conventional circuit shown in FIG. 1, the capacitances of the phase compensation capacitors C ₀₁ and C ₀₂ at the critical point where hunting occurs are each 200 μF. On the other hand, in the case of the circuit of the present invention, by setting the resistance value of the dividing resistor R ₁₁ to 120Ω, the capacitance of the phase compensation capacitor C ₀₁ can be reduced.
0.33μF, and the capacitance of C ₀₂ can be set to 5.4μF, which is about 1/666 when compared with the capacitor C ₀₁ . Therefore, hunting due to phase lag can be prevented by using a capacitor with a capacity significantly smaller than that of the conventional capacitor, and the distance between the converter device and the load, that is, the distance for remote sensing can be increased without being limited by the capacitance of the capacitor.

In this comparison experiment, the value of the voltage dividing resistor for load voltage detection of constant voltage control circuit 2 was set to R ₁₂ = 880Ω.
(Therefore, R ₁ = 1KΩ), R ₂ = 910Ω, and VR ₁ = 2KΩ.

Furthermore, the phase compensation capacitor C ₀₁ of this invention has a low resistance of 120Ω, which is much larger than its impedance (4.8Ω at a driving frequency of 100KHz).
Since R ₁₁ enters directly, the capacitor before startup
The charging voltage of C ₀₁ is suppressed so low that it does not pose a problem compared to the conventional circuit. Therefore, unlike the conventional circuit, the action of the voltage tracking circuit 1 does not cause an abnormal increase in voltage, and the action of the overvoltage detection circuit 4 turns off the converter main body 3, resulting in startup failure. Not at all.

As is clear from the above explanation, according to the present invention, there is no limitation on the remote sensing distance, and furthermore, there is no startup failure due to the charging voltage of the compensation capacitor, and the phase delay of the output circuit is achieved by using a small capacitance phase compensation capacitor. This prevents hunting caused by the converter, and has a great effect in redundant operation of the converter.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a general configuration example of a converter and a parallel connection state in redundant operation, Fig. 2 is a partial circuit diagram for explaining startup failure due to charging voltage of a compensation capacitor, and Fig. 3 is a circuit diagram showing an example of the converter's parallel connection in redundant operation. FIG. 2 is a circuit diagram showing an example. CON ₁ , CON ₂ , CON ₃ ... converter device,
D ₁ , D ₂ , D ₃ ... Backflow blocking diode, O ₁ , O ₂
...output terminal, RS ₁ , RS ₂ ...remote sensing terminal, OS ₁ , OS ₂ ...output wiring, rs ₁ , rs ₂ ...
... Wiring for remote sensing, L ... Load, L ₁ ,
L ₂ ... Load terminal, DL ... Dead load, C ₀₁ , C ₀₂ ...
Phase compensation capacitor, 1...voltage tracking circuit,
Tr...Control transistor, 2...Constant voltage control circuit, _R1 , _R2 and _VR1 ...Voltage dividing resistor for load voltage detection, _R11 , _R12 ...Dividing resistor, E _s1 ...Reference Voltage source, AMP... Voltage comparison amplifier, 3... Converter main body, 4... Overvoltage detection circuit, R ₃ , R ₄ ,
VR ₂ ...Voltage dividing resistor, E _s2 ...Reference voltage source, COP...
...comparison circuit.

Claims (1)

[Scope of utility model registration request] In a converter device that is connected to another converter device via a backflow blocking diode and that performs redundant operation by controlling a voltage tracking circuit and a constant voltage control circuit by remote sensing,
One end of the phase compensation capacitor is connected to the positive output terminal of the converter, and the other end is connected to the positive remote sensing terminal using a part of the voltage dividing resistor for detecting the load voltage of the constant voltage control circuit, A converter device characterized in that a second phase compensation capacitor is connected between a negative electrode side output terminal and a remote sensing terminal to prevent hunting due to a phase lag in a detected load voltage due to remote sensing.