Same-frequency waveform phase difference acquisition circuit based on DSP

Abstract

The utility model discloses a same-frequency waveform phase difference acquisition circuit based on a DSP (Digital Signal Processor), which comprises a voltage shaping circuit used for accessing a three-phase alternating current and a photoelectric coupler connected with the voltage shaping circuit, a three-phase alternating current passes through the first resistor and the voltage-regulator tube and then is transmitted to the photoelectric coupler, and the photoelectric coupler is used for converting and shaping the three-phase alternating current into a low-pulse square wave signal. According to the utility model, the phase difference is utilized to judge whether the three-phase input is open-phase or not, and when the phase difference exceeds a specified value, the input is judged to be open-phase so as to carry out protection, thereby solving the problems of open-phase and incapability of protection in the input open-phase protection of the aviation AC / DC power converter.

Description

Technical Field

[0001] This utility model relates to the field of phase difference acquisition technology for input waveforms of aviation AC / DC power converters, specifically a phase difference acquisition circuit for same-frequency waveforms based on DSP. Background Technology

[0002] Aviation AC / DC power converters output a stable DC voltage under AC input conditions. Currently, there are three methods to determine if the input power supply of an aviation AC / DC power converter is missing a phase: the first is to use a three-phase vector summation method; the second is to judge based on the three-phase input voltage acquisition; and the third is to judge based on the change in the phase sequence of the three input phases after detecting a phase loss. Since each of these three methods has its drawbacks, they cannot achieve phase loss detection and protection without false alarms or failure to protect under various operating conditions. Currently, domestic AC / DC power converters suffer from false alarms and failure to protect against phase loss. Therefore, a DSP-based circuit for acquiring phase difference of the same-frequency waveform is proposed. Utility Model Content

[0003] The purpose of this invention is to provide a DSP-based circuit for acquiring phase difference of waveforms at the same frequency, in order to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A DSP-based circuit for acquiring phase difference of waveforms at the same frequency includes a voltage shaping circuit for receiving three-phase AC power and an optocoupler connected to the voltage shaping circuit. The voltage shaping circuit includes a first resistor and a Zener diode. The three-phase AC power is transmitted to the optocoupler after passing through the first resistor and the Zener diode. The optocoupler is used to convert and shape the three-phase AC power into a low-pulse square wave signal. The output terminal of the optocoupler is connected to a DSP controller.

[0006] Furthermore, the optocoupler is used to isolate and transmit the input voltage signal and to perform shaping. A resistor is connected between the VCC output terminal of the optocoupler and the DSP controller, and the optocoupler adopts the GH281-4F type optocoupler.

[0007] Furthermore, the resistor assembly includes resistors R1, R2, and R3. The input terminal of resistor R1 is connected to an optocoupler to output the A-phase shaping signal of the three-phase AC power, the input terminal of resistor R2 is connected to an optocoupler to output the B-phase shaping signal of the three-phase AC power, and the input terminal of resistor R3 is connected to an optocoupler to output the C-phase shaping signal of the three-phase AC power.

[0008] Furthermore, the voltage range of the three-phase AC input detection line connected to the input terminal of the voltage shaping circuit is 40V-125V.

[0009] The beneficial effects of this utility model are as follows: Under the action of the DSP controller, this utility model reads the rising edge time difference of two waveforms of the same frequency to calculate the phase difference of the two waveforms of the same frequency, and uses the phase difference to determine whether the three-phase input is missing a phase. When the phase difference exceeds the specified value, it is determined that the input is missing a phase and thus provides protection. This solves the problem of phase loss protection in aviation AC / DC power converters, which is not possible. It is conducive to the promotion and use of this DSP-based waveform phase difference acquisition circuit. Attached Figure Description

[0010] Figure 1 This is the schematic diagram of the present invention.

[0011] In the diagram: 1 Voltage shaping circuit, 11 Zener diode, 12 Resistor 1, 2 Optocoupler, 3 DSP controller. Detailed Implementation

[0012] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0013] Please see Figure 1 This invention provides a technical solution for a DSP-based synchronous waveform phase difference acquisition circuit, comprising a voltage shaping circuit 1 for receiving three-phase AC power and an optocoupler 2 connected to the voltage shaping circuit 1. The voltage range of the three-phase AC power input detection line connected to the input terminal of the voltage shaping circuit 1 is 40V-125V. The voltage shaping circuit 1 includes a first resistor 12 and a Zener diode 11. The three-phase AC power is transmitted to the optocoupler 2 after passing through the first resistor 12 and the Zener diode 11. The optocoupler 2 is used to convert and shape the three-phase AC power into a low-pulse square wave signal. The output terminal of the optocoupler 2 is connected to a DSP controller 3.

[0014] In this embodiment, the aforementioned optocoupler 2 is used to isolate and transmit the input voltage signal and to perform shaping. A resistor assembly is connected between the VCC output terminal of the optocoupler 2 and the DSP controller 3. The optocoupler 2 adopts, but is not limited to, the GH281-4F type optocoupler. The resistor assembly includes resistors R1, R2, and R3. The input terminal of resistor R1 is connected to the optocoupler 2 to output the A-phase shaping signal of the three-phase AC power. The input terminal of resistor R2 is connected to the optocoupler 2 to output the B-phase shaping signal of the three-phase AC power. The input terminal of resistor R3 is connected to the optocoupler 2 to output the C-phase shaping signal of the three-phase AC power.

[0015] This DSP-based same-frequency waveform phase difference acquisition circuit uses an optocoupler 2 to isolate and shape the wide-bandwidth, wide-voltage input voltage signal because the three-phase input voltage of the permanent magnet converter is high and there is no neutral (N) line. The three-phase AC power enters the optocoupler 2 after passing through resistor 12 and Zener diode 11, and is converted into low-pulse square wave signals A, B, and C. The input three-phase square waves are differentially sampled and then fed into an external AD converter before entering the DSP controller 3. The DSP controller 3 obtains the phase difference of the same-frequency waveform. This DSP-based same-frequency waveform phase difference acquisition circuit shapes the input voltage waveform into a square wave signal and sends it to the DSP controller 3, which then obtains the phase difference between the two phases of the input AC voltage.

[0016] In summary, this DSP-based same-frequency waveform phase difference acquisition circuit, under the action of the DSP controller 3, reads the rise time difference of two same-frequency waveforms to calculate the phase difference between them. Furthermore, it uses the phase difference to determine whether a phase is missing in the three-phase input. When the phase difference exceeds a specified value, it determines that the input phase is missing and thus provides protection. This DSP-based same-frequency waveform phase difference acquisition circuit fills the gap in obtaining the phase difference of input waveforms in aviation AC / DC power converters, and also fills the gap in obtaining the phase difference of AC input waveforms in aviation power equipment. It can also be extended to other fields that require obtaining the phase difference of input AC voltage.

[0017] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0018] The above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be understood that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present utility model, and these all fall within the protection scope of the present utility model. In the present utility model, unless otherwise explicitly specified and limited, the terms "installation", "connection", "joining", "fixing", etc. should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components. Among them, there are various ways of detachable installation, such as by plugging and snapping, or by bolt connection, etc.

[0019] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A DSP-based circuit for acquiring phase difference of same-frequency waveforms, characterized in that: It includes a voltage shaping circuit for receiving three-phase AC power and an optocoupler connected to the voltage shaping circuit. The voltage shaping circuit includes a first resistor and a Zener diode. The three-phase AC power is delivered to the optocoupler after passing through the first resistor and the Zener diode. The optocoupler is used to convert and shape the three-phase AC power into a low-pulse square wave signal. The output terminal of the optocoupler is connected to a DSP controller.

2. The DSP-based phase difference acquisition circuit for same-frequency waveforms according to claim 1, characterized in that: The optocoupler is used to isolate and transmit the input voltage signal and to perform shaping. A resistor is connected between the VCC output terminal of the optocoupler and the DSP controller. The optocoupler is a GH281-4F type optocoupler.

3. The DSP-based phase difference acquisition circuit for same-frequency waveforms according to claim 2, characterized in that: The resistor assembly includes resistors R1, R2, and R3. The input terminal of resistor R1 is connected to an optocoupler to output the A-phase shaping signal of the three-phase AC power, the input terminal of resistor R2 is connected to an optocoupler to output the B-phase shaping signal of the three-phase AC power, and the input terminal of resistor R3 is connected to an optocoupler to output the C-phase shaping signal of the three-phase AC power.

4. The DSP-based phase difference acquisition circuit for same-frequency waveforms according to claim 1, characterized in that: The voltage range of the three-phase AC input detection line connected to the input terminal of the voltage shaping circuit is 40V-125V.

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