JP3338395B2 - Power supply oscillation detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductance caused by a feed line length of a DC power supply, a negative resistance caused by a constant power load device represented by a switching regulator, and an input filter of the load device. The present invention relates to a device for detecting an oscillation phenomenon caused by an input capacitor to detect a danger such as breakage of a power supply facility.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing a configuration of a conventional power supply system oscillation detecting device and a connection relationship between the power supply system oscillation detecting device and a DC power supply system. In the figure, when the power P of the constant power load device 1 increases to some extent, the equivalent load resistance of the constant power load device 1 viewed from the power supply voltage source 2 becomes negative resistance, and the negative resistance value exceeds a certain critical value. And the feed line inductance L and the input capacitor C built in the constant power load device.
An oscillation phenomenon of a frequency determined by i occurs. In many cases, the amplitude voltage of this oscillation rapidly increases to the range of the input voltage at which the constant power load device 1 can maintain the constant power property,
As a result, the constant power load device 1 is destroyed. For this reason, conventionally, when such an oscillation phenomenon occurs in the power supply system, the power supply system oscillation detection device 3 uses the amplitude suppression circuit 4 including the transistor Q, the diode D, the capacitor C, the resistor R1, and the resistor R2 to output the positive electrode. The configuration is such that an AC component, which is a voltage oscillation between the power supply line 12 and the negative power supply line 13, is suppressed within 2 Vp-p. Here, the voltage amplitude due to the oscillation of the power supply system is suppressed to avoid destruction of the constant power load device 1, and at the same time, the oscillating voltage suppressed by the amplitude suppression circuit 4 is passed through the time constant circuit including the capacitor Cc and the resistor R3 to the comparator CP. Detects the amplitude voltage value, and when the voltage value exceeds a predetermined voltage value, the flip-flop FF operates and the buzzer B
The oscillation detection / warning circuit 5 for sounding U informs that the power supply system has entered the oscillation state.

[0003]

However, when the power P of the constant power load device 1 in the power supply system is relatively small and the power supply system is in an oscillation state close to the critical point between oscillation and non-oscillation,
The oscillation state may be stopped due to the influence of additional impedance such as stray capacitance caused by connecting the power supply system oscillation detection device 3 to the power supply system. Therefore, oscillation detection
The alarm circuit does not operate, and cannot detect that the power supply system is in the oscillation state. As a result, the power supply system is erroneously recognized as a stable state, and the power supply system oscillation detecting device 3 is removed from the power supply system, and at the same time, is released from the additional impedance and the power supply system oscillates, thereby leading to a situation in which the constant power load device is destroyed. There was a problem.

[0004] In order to solve the above problems, the present invention provides:
When the oscillation condition of the power supply system is near critical and not in an apparent oscillation state, an apparent oscillation state is intentionally generated to notify that the power supply system is in the oscillation state or the critical state of oscillation. An object is to prevent a power supply system oscillation accident caused by removing the detection device 3 beforehand.

[0005]

According to the present invention, there is provided a constant power load which can start the above-described oscillation between a positive electrode and a negative electrode in a power supply system oscillation detecting device as required. By connecting this constant power load to the feed line as needed and starting the oscillation, the oscillation state is intentionally generated even when the oscillation condition of the feed system is near the critical state and there is no obvious oscillation state. This makes it possible to notify that the power supply system is in an oscillating state or a state immediately before the oscillating state. That is,
According to claim 1 of the present invention, a DC voltage source and a
A constant power load device having a capacitor;
A power supply line for connecting to the constant power load device.
Power supply oscillation detection to detect oscillation phenomena in the power feed system
The device, before relatively close to the constant power load device
A positive electrode connected to the positive power supply line of the power supply line, and the power supply line;
A negative electrode connected to the negative electrode power supply line, and the positive electrode and the negative electrode
And the DC power supply system oscillates
The oscillation voltage generated between the positive power supply line and the negative power supply line
An amplitude suppression circuit for suppressing the width, and
Connected between the detecting and detecting the suppressed oscillation voltage
Oscillation detection that reports that the DC power supply system is in oscillation
An alarm circuit, and the amplitude suppression between the positive electrode and the negative electrode.
Control circuit and the oscillation detection / alarm circuit in parallel.
The constant power load and the activation of the constant power load.
Operating means, wherein the constant power load is
The DC power supply system load
Connected, and oscillates the oscillation of the DC power supply system immediately before oscillation.
Power supply oscillation detection device configured to be forcibly started
It is stipulated. In claim 2, DC voltage
Source, a constant power load with a capacitor at the input, and
A power supply line connecting the DC voltage source and the constant power load device
For detecting the oscillation phenomenon in the DC power supply system having
A power supply system oscillation detection device, which is compared with the constant power load device.
A positive electrode connected to a positive power supply line of the power supply line relatively close to the power supply line
A negative electrode connected to a negative power supply line of the power supply line;
Connected between a positive electrode and the negative electrode, the DC power supply
Generated between the positive and negative electrode feed lines due to vibration
An amplitude suppressing circuit for suppressing the amplitude of the oscillation voltage,
And the suppressed oscillating voltage connected between the
To notify that the DC power supply system is in oscillation.
Between the positive electrode and the negative electrode.
And the amplitude suppression circuit and the oscillation detection / alarm circuit.
And a constant power load connected through a switch in parallel to
The constant power load is connected to the DC
Just before oscillation when connected as a load in the feed system
The DC power supply system is configured to forcibly start oscillation.
It specifies the power supply system oscillation detection device. Claim
3. The power supply system oscillation detection according to claim 1 or 2, wherein
In the device, the constant power load is connected to the DC / DC converter.
Stipulates the power supply oscillation detection device composed of
I have.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The present embodiment is an example, and it goes without saying that various changes or improvements can be made without departing from the spirit of the present invention, for example, by connecting a constant power load to be built in to the outside as appropriate. . FIG. 1 shows a configuration in which a constant power load 6 according to the present invention is realized by a DC / DC converter 10 and a load resistor RL, and oscillation can be started at any time by a start switch 7. Hereinafter, each component shown in FIG. 1 will be described.

[0007] In the amplitude suppression circuit 4 in FIG.
The collector of the n-transistor Q is connected to the positive power supply line 12 via the resistor R2 as the positive electrode of the amplitude suppression circuit 4,
The emitter is connected to the negative power supply line as the negative electrode of the amplitude suppression circuit 4. Here, a capacitor C is inserted between the collector and the base, and a resistor R1 is connected between the base and the emitter to set a voltage between both ends of the capacitor C.
Also, a diode D for discharging the electric charge accumulated in the capacitor C in the negative half cycle in the positive half cycle of the oscillation waveform and resetting the voltage is connected between the base and the emitter of the transistor Q. The collector resistance R2 is connected between the collector and the positive electrode power supply line so as to prevent the transistor from operating in a safe operation range.

In such a circuit configuration of the amplitude suppressing circuit 4, when the load power P exceeds the oscillation critical level and the power supply system oscillates, the positive power supply line 12 of the power supply line which is the input voltage of the constant power load device 1 and the negative power supply line 12 The input voltage V between the electric wires 13 oscillates. In the positive half cycle of the oscillation, when the input voltage V rises due to vibration and becomes higher than the initial voltage of the capacitor C, a charging current starts to flow to the capacitor C via the base resistor R1. Further, when the input voltage V exceeds the sum of the initial voltage and the voltage between the base and the emitter of the transistor Q, most of the charging current of the capacitor C becomes the base current of the transistor Q, and the transistor Q is activated. As a result, the collector current of the transistor Q flows by the current amplification factor times the base current, and the oscillating current of the power supply system is bypassed before the constant power load device 1. No charge to be charged by oscillation is accumulated. As a result, the input capacitor Ci
Only rises to the sum of the initial voltage and the base-emitter voltage of the transistor Q. As a result,
In the negative half cycle of the oscillation, the initial voltage relating to the oscillation of the input capacitor Ci becomes equal to the base-emitter voltage. Therefore, the maximum value of the negative amplitude of the input voltage V of the constant power load device 1 is also equal to the base-emitter voltage. It is almost equal. Therefore, the operating waveform of the input voltage V of the constant power load device 1 has a base amplitude with respect to the power supply voltage E of the DC supply voltage source 2.
The fluctuation is suppressed to about the voltage between the emitters. Since the base-emitter voltage of a transistor is generally 1 V or less, the peak value of the oscillation voltage amplitude in this power supply system is within 2 Vp-p in the case of a bipolar transistor as in this example, and in the case of a field-effect transistor. Is 2.5Vp-
p, and the constant power load device is not destroyed.

The collector resistor R2 connected between the collector of the transistor Q and the positive power supply line 12 is a protection resistor for limiting the flow of an excessive current to the transistor Q. It is intended to operate with. The diode D implements a voltage reset function for discharging the electric charge accumulated in the capacitor C in the positive half cycle of the oscillation in the negative half cycle. Further, the base resistor R1 makes the initial value voltage of the capacitor C equal to the DC power supply voltage E, turns off the transistor Q when no oscillation occurs in the power supply equipment, and prevents the circuit from malfunctioning due to a weak noise voltage. This is a stabilizing resistor to avoid.

The oscillation detection / alarm circuit 5 shown in FIG.
When the power supply system oscillates, the positive power supply line 12
And the AC component, which is the voltage oscillation of the voltage between the negative power supply line 13 and the negative electrode power supply line 13, is suppressed within 2 Vp-p, but the oscillation does not completely stop. Therefore, the continuous AC component within 2 Vp-p is converted to the DC cut-off capacitor Cc and the detection resistor R3.
And can be detected through a time constant circuit constituted by The detected AC component has a threshold voltage inverted by a voltage within 2 Vp-p determined by the characteristics of the transistor. Is set, and the buzzer BU is sounded by the output of the flip-flop FF to notify the oscillation state, that is, the overload state.

A feature of the present invention is that a constant power load circuit 6 for adding a load to the feeder line 8 in addition to the above two functional circuits.
Is connected. That is, by adopting the configuration shown in FIG. 1, even when the power supply system including the power supply line 8 does not cause obvious oscillation near the critical condition of the oscillation condition,
Before removing the power supply system oscillation detecting device 9 from the power supply system including the power supply line 8, the DC / DC converter 10
Is set to an operating state by the start switch 7 so that the power supply system is in a load state, and the total of the constant power loads of the power supply system is increased from the original load P of the constant power load device 1, and the power supply system is forced. Oscillation causes the oscillation detection and alarm circuit 5
It is possible to detect the oscillation state or the oscillation critical state.

FIG. 2 shows another embodiment of the present invention.
The C / DC converter 10 is connected to the power supply line 8 by the switch 11.
Is connected or disconnected as the load of the power supply system including That is, the oscillation state is created by setting the switch 11 to the connected state, and this oscillation is detected by the oscillation detection / warning circuit 5.

When the power supply system is in a stable state close to the critical condition of the oscillation condition, the present invention may be changed from a stable state to an oscillation state. In any case, the power supply system is in a state close to the oscillation critical condition. Therefore, from the viewpoint of taking measures to suppress oscillations in the power supply system, even if a false alarm results, it is a false alarm in a safe direction and does not pose a practical problem.

[0014]

As described above, according to the present invention, when the load is temporarily increased for the test, the power supply system is not clearly oscillating around the critical condition of the oscillating condition and the oscillating state cannot be detected. However, since the oscillation state is intentionally created, the oscillation state including the possibility of oscillation can be detected.Therefore, by mistakenly removing the power supply system oscillation detection device, the power supply system may oscillate. There is an effect that a situation in which the load device is broken can be prevented.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating an embodiment of the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a conventional power supply system oscillation detection device and connection to the power supply system.

[Explanation of symbols]

 1: Constant power load device 2: Supply voltage source 3: Power supply system oscillation detection device 4: Amplitude suppression circuit 5: Oscillation detection / warning circuit 6: Constant power load 7: Start switch 8: Power supply line 9: Power supply system oscillation detection device 10: DC / DC converter 11: Switch BU: Buzzer Ci: Input capacitor Cc, C: Capacitor CP: Comparator D: Diode FF: Flip-flop R1, R2, R3: Resistance

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G05F 1/10

Claims (3)

(57) [Claims] 1. A DC voltage sourceWhen,Has a capacitor at the inputTo
SetPower load deviceAnd the DC voltage source and the constant power load device.
In a DC power supply system with a power supply line connecting the
A power supply oscillation detection device for detecting a phenomenon,  PreviousInscriptionPositive electrode of the feeder line relatively close to the power load
On the feederConnectedA positive electrode,Of the feeder Negative feederConnectedNegative electrodeWhen, The direct current connected between the positive electrode and the negative electrode Power supply system
Oscillation between the positive and negative electrode power supply linesDeparture
LiveOscillation voltageofSuppress amplitudeAn amplitude suppression circuit; Connected between the positive electrode and the negative electrode, Suppressed
Detecting oscillating voltageDCMake sure that the power supply system is in oscillation.
AnnounceOscillation detection / alarmCircuit and,  The positive electrode and the negative electrodeWhenBetween,The amplitude suppression circuit;
Connected in parallel with the oscillation detection / alarm circuitConstant power negative
loadWhen, Starting means for setting the constant power load to an operating state, The constant power load is activated by the starting unit.
Is connected as a load of the DC power supply system, Departure
Just before the shakeDCOscillation of power supply systemForce start
likeConstitutionWas donePower supply system oscillation detection device characterized by the above-mentioned.
Place. (2)Has a DC voltage source and a capacitor at the input
A constant power load device, the DC voltage source and the constant power load device;
In a DC power supply system with a power supply line connecting the
A power supply oscillation detection device for detecting a phenomenon, Positive electrode of the feed line relatively close to the constant power load device
A positive electrode connected to the power supply line, A negative electrode connected to a negative power supply line of the power supply line; The DC power supply system connected between the positive electrode and the negative electrode;
Oscillation between the positive and negative power lines.
An amplitude suppression circuit for suppressing the amplitude of the generated oscillation voltage; Connected between the positive electrode and the negative electrode,
The oscillation voltage is detected and the DC power supply system is in an oscillation state.
An oscillation detection / alarm circuit that notifies Between the positive electrode and the negative electrode, the amplitude suppression circuit and
Connected via a switch in parallel with the oscillation detection / alarm circuit.
Connected with a constant power load, The constant power load is connected to the DC power supply by the switch.
When connected as a system load,
It is configured to forcibly start the oscillation of the DC power supply system.
 A power supply oscillation detection device, characterized in that: 3. A feeding system oscillation detection apparatus according to claim 1 or 2, wherein the constant power load and the DC / DC converter resistor
And a power supply system oscillation detecting device.