JP3212369B2 - Inverter drive signal detection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply system used as a power supply for a large computer or the like, in which a monitoring and monitoring device adopted for maintaining high reliability is provided. The present invention relates to a drive signal detection circuit for detecting a drive signal current of an inverter main transistor among various sensors which must be added to detect various data in the device.

[0002]

2. Description of the Related Art Recently, the demand for high reliability of an uninterruptible power supply has been increasing. Preventive maintenance through daily maintenance and inspection is important to maintain the high reliability of the uninterruptible power supply.On the other hand, in the event of accidental failure of parts, the system is made redundant to avoid system failure in the event of a failure. The so-called post-maintenance, which performs maintenance by disconnecting the uninterruptible power supply urgently, is mainly used. Therefore, in order to realize a quick recovery, a self-diagnosis function is provided so as to instantaneously and accurately grasp the state of the failure, and a monitoring and monitoring device is employed. In each case, the voltage and current waveforms of the main part are constantly monitored and recorded, and when a failure occurs, the waveforms before and after the occurrence are reproduced, thereby immediately analyzing and examining the abnormal data and enabling quick response. In order to enable such a system, the uninterruptible power supply device is provided with various sensors for detecting data of each unit, and its control circuit transmits various digital and analog information to the monitoring monitor device. Although a circuit for transmission is included, an inverter drive signal current sensor is not included.

[0003]

In particular, when the information of the control circuit is to be monitored, a large change of the control circuit is required and the reliability may be poor. The present invention has been made in view of the above points, and an object thereof is to provide a drive signal detection circuit for an inverter which is capable of catching an abnormality in a control circuit simply by adding a simple and inexpensive sensor. To provide.

[0004]

The means for achieving the object is to monitor the abnormality of the control circuit and to monitor the drive signal current of the inverter main transistor, which is the final output signal of the control circuit. As a current detection sensor,
There are shunts, AC current transformers (hereinafter, ACCT), DC current transformers (hereinafter, DCCT), and the like. However, shunts have the disadvantage that they cannot be measured without contacting the circuit to be measured and that they become a load. is there. For DCCT, a control power supply is required, and uninterruptible power supply of the power supply must be considered, resulting in high cost. In comparison with these, the ACCT has the advantage that it can be insulated from the circuit to be measured and can be used without a power supply. However, the drive signal current of the uninterruptible power supply inverter main transistor to be monitored now is a PWM signal, but at a DC level. Therefore, ACC
If T is used, the iron core may be saturated and an appropriate output signal may not be obtained.

Therefore, in the present invention, the first order of ACCT is:
The drive signal currents of the P-side transistor and the N-side transistor of the pair of inverters are applied so that they are opposite to each other. This is based on the fact that the drive signal of the inverter main transistor is shifted by 180 degrees between the P-side transistor and the N-side transistor so as not to cause a DC bus short circuit. That is, ACCT
Therefore, the combined drive signal of the P side and the N side applied to the primary side is converted into an alternating current, and saturation of the ACCT can be prevented.
Since the signal on the primary side of the ACCT is converted into an AC signal, the output is also an AC signal. There is no problem if it is input to the monitoring device as it is, but when analyzing the recorded waveform, "
It is necessary to discriminate between the P-side signal and the "N-side signal." Therefore, by rectifying and separating the AC-converted output, a waveform similar to the original P-side drive signal and N-side drive signal is obtained as an output. Can be

The operation will be described in conjunction with the embodiment described below. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0006]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, and FIG.
FIG. 2 is a circuit diagram showing one embodiment of the waveform shaping circuit of FIG.
1 is a DC power supply, 2 is an inverter section, 3 is an inverter section 2
The driving circuit of the main transistor module,
4 is an ACCT added in the present invention, 5 is a waveform shaping circuit for separating and rectifying a signal detected by the ACCT 4, 21, 22, and 23 are main transistor modules (hereinafter simply referred to as main transistors), and 51 and 52 are photocouplers. In FIG. 1, the primary winding of the ACCT 4 added in the present invention is wound such that drive signals on the P-side and N-side of the main transistor of the inverter unit 2, for example, the main transistor 21, are opposite to each other. It is characteristic. This is, as mentioned above,
The drive signal of the VCF inverter main transistor is PW
Although the signal is an M signal, since it is a DC level, if ACCT is added to each signal as it is, the iron core of the ACCT is saturated and a normal output cannot be obtained. On the other hand, the drive signal of the inverter main transistor is, for example, the main transistor 21
Since the phases of the P side and the N side are usually shifted by 180 degrees, the two signals are turned in opposite directions to each other so that ACC
When penetrating through T, the drive signal synthesized for ACCT4 becomes an AC signal. Thus, saturation of ACCT4 can be prevented.

Further, according to the present invention, as shown in FIG.
As a primary side detection signal of CT4, for example, a main transistor
It is characterized in that the emitter signal line 33 is used among the 21 drive signals for the P side and the N side. This is because the drive signal current generated by the drive circuit 3 of the inverter main transistor always passes through the emitter signal line 33 to the original drive circuit 3.
It focuses on returning to. For example, when the load reactive current of the inverter circuit 2 flows through the flywheel diode in the inverter main transistor 21,
When the ACCT 4 is added to the base signal line 32 of the inverter main transistor drive signal, the drive signal current flows through the collector signal line 31 without passing through the base signal 32 even though the drive circuit 3 drives at a constant current.
, The signal level becomes very small and detection becomes difficult. However, the drive signal current always returns to the drive circuit 3. The path is the emitter signal line 33. AC
Since the primary side signal of CT4 has been converted to AC, this output signal is an AC signal. There is no problem if it is input to the monitoring device as it is, but when analyzing the recorded waveform, it is necessary to determine the “P-side drive signal” and the “N-side drive signal” from the AC signal. Therefore, if the waveform shaping circuit 5 is provided to separate and rectify the "P-side drive signal" and the "N-side drive signal", a waveform equal to the original drive signal can be obtained, and the recorded waveform analysis can be easily performed. Become.

[0008]

As described above, according to the present invention, when a monitoring and monitoring apparatus is used to record and monitor the state of a control circuit, a large change of the control circuit is not required, and the monitoring circuit is quite simple and inexpensive. It becomes possible only by adding ordinary ACCT as a sensor, and it becomes possible to install a monitoring and monitoring device in existing equipment.

[0009]

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a circuit diagram showing one embodiment of a waveform shaping circuit of FIG. 1;

[0010]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 21 Main transistor 2 Inverter part 3 Drive circuit 33 Emitter signal line 4 AC current transformer 5 Waveform shaping circuit

Claims (1)

(57) [Claims] 1. A signal detection circuit for detecting a drive signal current of an inverter main transistor of a monitoring and monitoring device added to an uninterruptible power supply system, wherein said signal detection circuit is connected between both terminals of a DC power supply and driven by a signal from the drive circuit. Of the drive signal lines of the respective main transistors on both sides of the DC power supply of the inverter unit, the emitter signal line is
Inverter drive characterized in that it passes through the AC current transformer between the inverter unit and the drive circuit in the opposite direction to convert the signal into AC and outputs a waveform that is equivalent to the original DC power supply bipolar drive signal Signal detection circuit.