CN201340444Y - Module for detecting residual voltage frequency of generator - Google Patents

Abstract

The utility model discloses a generator residual voltage frequency detection module, which includes a voltage stabilizer, a sampling circuit, and an amplifier circuit, and is characterized in that it also includes a protection circuit, an adjustment circuit, and a shaping output circuit, wherein the protection circuit includes a Hall sensor; the adjustment circuit includes an operational amplifier and a hysteresis comparator; the shaping output circuit includes a comparator; the above circuit is connected to the front and back circuits through the pins drawn out of the module. The utility model solves the problem of accurate and reliable measurement of the ultra-low amplitude and ultra-low frequency of the residual voltage signal of the generator, and the signal frequency in a wide range of signal amplitude and frequency.

Description

A generator residual voltage frequency detection module

technical field

The utility model relates to a detection module for the residual voltage signal frequency of an electric speed measurement mode of a rotational speed measurement and control device, in particular to a detection module for the residual voltage frequency of a generator.

Background technique

With the continuous improvement of the automatic control system of generator sets, the reliability requirements for unit speed measurement and protection are getting higher and higher. At present, most speed measuring devices use both mechanical and electrical speed measurement principles in the same device. The residual voltage signal is converted into a signal suitable for subsequent circuit processing by means of PT transformer or resistor divider, which makes it difficult to accurately and reliably measure the residual voltage signal at ultra-low amplitude and ultra-low frequency. Although there are PTs that collect small signals Or circuit but can not meet the signal measurement when the amplitude of the residual voltage signal is high, there are many unit speed measurement devices that use the combination of mechanical speed measurement principle and electrical speed measurement principle, adopt the mechanical speed measurement principle at low frequency, and use electrical speed measurement at high frequency The principle is to ensure the accuracy and precision of the device's measurement at ultra-low amplitude and ultra-low frequency. All produced bad influence to the reliability of device, accuracy and flexibility like this.

Therefore, how to accurately and reliably measure the residual voltage signal at ultra-low amplitude and ultra-low frequency while ensuring accurate and reliable measurement of the residual voltage signal amplitude and frequency in a wide range has become an urgent problem to be solved.

Contents of the invention

1. Purpose of the invention

Aiming at the deficiencies of the prior art, the utility model proposes a generator residual voltage frequency detection module, which can accurately and reliably measure the ultra-low range, ultra-low frequency and wide range of the generator residual voltage signal.

2. Technical solution

The utility model is a detection module for the generator residual voltage frequency, which is mainly used to solve the detection problem that it is difficult to accurately and reliably measure the frequency when the generator residual voltage signal is ultra-low frequency and ultra-low amplitude. The module circuit is composed of a voltage stabilizer, a sampling circuit, an amplifier circuit, a protection circuit, an adjustment circuit and a shaping output circuit. The protection circuit includes a Hall sensor; the adjustment circuit includes an operational amplifier and a hysteresis comparator; and the shaping output circuit includes a comparator.

3. Beneficial effects

The utility model solves the problem of accurate and reliable measurement of the ultra-low amplitude and ultra-low frequency of the residual voltage signal of the generator, and the signal frequency in a wide range of signal amplitude and frequency. The utility model module has the characteristics of small packaging volume, wide measurement range, accurate and reliable measurement, strong anti-interference ability and low cost, and provides a cost-effective detection method for the unit speed measurement and control device with increasingly higher requirements. In addition, if the special transformer T1 is removed, the Hall sensor can detect the changing magnetic field strength through other methods such as distance, and at the same time, the follow-up circuit and parameters of the Hall sensor can be properly adjusted to form different types of Hall switch circuits. It can be as high as more than ten K, which meets the detection function of most Hall sensors as switches. Provide reliable and accurate detection signals for subsequent processing circuits.

Description of drawings

Fig. 1 is the schematic diagram of the utility model

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

The generator residual voltage signals IN1 and IN2 are introduced into the special transformer T1 winding, and an alternating magnetic field B is generated in the core of T1. The changing magnetic field B is detected by the Hall sensor IC1. When there is no external residual voltage signal, there is no magnetic field in the core of the special transformer. The hall sensor IC1 outputs a stable voltage value U. When IN1 and IN2 have residual voltage signal input, an alternating magnetic field is generated in the core of T1. IC1 detects the changing magnetic field, and its output voltage changes accordingly. The changing law is Rising or falling from U, the rising or falling voltage value is related to the polarity and strength of the magnetic field.

The adjustment circuit uses a high-performance op amp to form an amplification and lag comparator functional circuit to process the sampled voltage signal, and then a high-performance comparator forms a shaping circuit to output a switching signal with the same frequency as the input signal to control the pass through of the triode. The final module outputs a switching signal with the same frequency as the input signal.

Through calculation and proper selection of devices, this module can perform signal frequency control on amplitudes within 0.2V≤Uin≤250V (this value is effective, corresponding to peak-to-peak voltages of 0.566V-707V) and frequencies within 0.1Hz≤F≤150Hz Reliable and accurate measurements. This new type of module circuit IC devices are all packaged in SO8 and SO14, resistors and capacitors are packaged in 0805, most of the rest of the devices are packaged in smaller surface mount packages, and these devices are welded on a smaller PCB circuit board, And put it in a metal shielding cover to solidify the package to form a modular circuit, and complete the connection with the front and rear circuits through the 5 pins drawn out of the module. In addition, each circuit part of the module of the utility model has a protection circuit, such as an input anti-differential mode, a common mode protection circuit, an operational amplifier protection circuit, etc., which enhances the reliability of the module circuit. The utility model has the characteristics of small size, high measurement accuracy, wide measurement range, good reliability, strong anti-interference ability, and can accurately and reliably measure the input signal frequency at ultra-low frequency, ultra-low amplitude and wide range of amplitude and frequency.

The input signal frequency can be accurately and reliably measured within the range of 0.2V≤Uin≤250V (effective value) and frequency within the range of 0.1Hz≤F≤150Hz. Generally, the electrical residual voltage signal is a sine wave. For The input signal of the utility model can also be a non-sine wave, but it cannot be a pulse signal with a step change, and the input signal should be a symmetrical waveform about the AC zero point. In practical applications, in order to prevent damage to internal devices and circuits when the input signal amplitude is high, the input signal needs to be connected with an external current-limiting resistor as shown in the figure below, and the resistance values of R1 and R2 must be selected to meet the current flowing into the circuit of the module used. No more than 200mA.

Claims (1)

1, a kind of generator residual voltage frequency detection module comprises voltage stabilizer, sample circuit, amplifying circuit, it is characterized in that, also comprises holding circuit, adjusts circuit and shaping output circuit, and wherein, described holding circuit comprises a Hall element; Described adjustment circuit comprises an operational amplifier and a hysteresis comparator; Described shaping output circuit comprises a comparer; The pin that foregoing circuit is drawn by module is connected with the front and back circuit.

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