Sine wave phase detection circuit and method of operation

Abstract

The sinusoidal wave phase detection circuit of this invention comprises a DC blocking filter, a zero-crossing hysteresis comparator, a level shifter, and a phase counting module, wherein the phase counting module is implemented based on a programmable logic device. The sinusoidal input signal, after passing through the DC blocking filter capacitor, is input to the zero-crossing hysteresis comparator circuit, generating a square wave signal in phase with the input sine wave. This square wave signal, after passing through the level shifter, is input to the phase counting module. The phase counting module determines the 0° phase point of the input sine wave signal by detecting the rising edge of the square wave signal and outputs a specific phase indication based on the 0° phase point. This invention features a simple circuit structure, a high degree of versatility, and can be widely applied in industrial fields.

Description

Technical Field

[0001] This invention belongs to the technical field of electronic circuits, and particularly relates to a sinusoidal wave phase detection circuit and its working method. Background Technology

[0002] As a typical measurement excitation in the industrial field, the accurate measurement of sine wave signals is of great significance for improving measurement accuracy and system reliability. As an important parameter of sine wave, effective detection of phase can often simplify hardware topology and software design and reduce costs. For example, in existing sine wave peak sampling circuits, due to the unknown phase, full-wave rectifier circuits are often used, which result in complex circuit structures and low efficiency in effective detection of sine wave phase.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a sine wave phase detection circuit and its operating method, which achieves effective detection of the sine wave phase, improves real-time detection performance, simplifies the hardware topology and software design of the sine wave peak sampling circuit, and reduces costs. The technical solution of this invention has many beneficial effects, as described below:

[0005] A sinusoidal wave phase detection circuit is provided, comprising a DC blocking filter capacitor, a level conversion circuit, and a phase counting circuit, and further including a zero-crossing hysteresis comparator circuit, wherein:

[0006] The output of the DC blocking filter capacitor is connected to the input of the zero-crossing hysteresis comparator, the output of the zero-crossing hysteresis comparator is connected to the input of the level conversion circuit, and the output of the level conversion circuit is connected to the input of the phase counting circuit.

[0007] The sinusoidal input signal is input to the zero-crossing hysteresis comparator after passing through the DC blocking filter capacitor, which generates a square wave signal in phase with the sinusoidal input signal. The square wave signal in phase is then input to the phase counting module after passing through the level conversion circuit.

[0008] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0009] The sinusoidal input signal, after passing through a DC blocking filter capacitor, is input to a zero-crossing hysteresis comparator circuit, generating a square wave signal in phase with the input sine wave. This square wave signal, after passing through a level conversion module, is input to a phase counting module. The phase counting module determines the 0° phase point of the input sine wave signal by detecting the rising edge of the square wave signal and outputs a specific phase indication based on the 0° phase point. This invention features a simple circuit structure, high versatility, and wide applicability in industrial fields. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of a sine wave phase detection circuit.

[0012] Figure 2 This is a schematic diagram of a sinusoidal wave phase detection method. Detailed Implementation

[0013] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0014] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this invention, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0015] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0016] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that aspects can be practiced without these specific details. To enable those skilled in the art to better understand the invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of that feature. In the description of the invention, unless otherwise stated, "a plurality of" means two or more.

[0017] Given the 90° phase point of a sine wave, the positive peak value of the sine wave can be obtained by directly acquiring the voltage value at the 90° phase point using an analog-to-digital converter (ADC). Further calculations can then be performed to obtain the effective value of the sine wave, without the need for full-wave rectification or capacitor charging and discharging. Figure 1 The sinusoidal wave phase detection circuit shown comprises a DC blocking filter capacitor, a level conversion circuit, and a phase counting circuit. It also includes a zero-crossing hysteresis comparator circuit, wherein:

[0018] The output of the DC blocking filter capacitor is connected to the input of the zero-crossing hysteresis comparator, the output of the zero-crossing hysteresis comparator is connected to the input of the level conversion circuit, and the output of the level conversion circuit is connected to the input of the phase counting circuit.

[0019] The sinusoidal input signal is input to the zero-crossing hysteresis comparator after passing through the DC blocking filter capacitor, which generates a square wave signal in phase with the sinusoidal input signal. The square wave signal in phase is then input to the phase counting module after passing through the level conversion circuit.

[0020] In the above, the DC blocking filter capacitor filters out the DC component of the input signal. The threshold for the zero-crossing hysteresis comparator output signal to change from low to high is 0V.

[0021] When the input voltage is higher than 0V, the output is high.

[0022] The zero-crossing hysteresis comparator circuit is used to generate a square wave signal that is in phase with the input sine wave signal. When the input sine wave changes from -0V to +0V, the output signal changes from low level to high level. At the same time, the hysteresis loop can filter out high-frequency glitches and improve anti-interference capability.

[0023] As a specific implementation provided in this case, the zero-crossing hysteresis comparator circuit includes resistors R1, R2, and R3, and an operational amplifier integrated circuit, wherein:

[0024] One end of resistor R1 is grounded, and the other end is connected to the positive input terminal of the operational amplifier and one end of resistor R2. The other end of resistor R2 is connected to the output terminal of the operational amplifier and one end of resistor R3. The other end of resistor R3 is a DC power supply.

[0025] The inverting input of the operational amplifier is connected to the input of the DC blocking filter capacitor, and the output is connected to the level shifting circuit. The phase counting module is implemented based on an FPGA and includes one timer, the duration of which can be configured according to the target phase.

[0026] A sine wave, after DC blocking and filtering, is input to a zero-crossing hysteresis comparator, generating a square wave signal in phase with the input sine wave. The 0° phase point of the sine wave is obtained by detecting the rising edge of the in-phase square wave signal, and a configurable timer is triggered at the 0° phase point. When the timer expires, a pulse signal is generated to indicate the target phase point. This invention achieves effective detection of the sine wave phase, improves real-time detection, simplifies the hardware topology and software design of the sine wave peak sampling circuit, and reduces costs.

[0027] Secondly, a method for operating a sinusoidal wave phase detection circuit is provided, which is applied to a sinusoidal wave phase detection circuit. The method includes:

[0028] Step 1: Configure the timer duration cnt of the phase counting module according to the target phase θ;

[0029] Step 2: After the phase counting module detects the rising edge of the in-phase square wave signal, it starts the timer.

[0030] Step 3: After the timer of the phase counting module expires (when the timer expires, it means the time has been incremented from zero to the timer duration cnt), a pulse signal is output to indicate the target phase.

[0031] Furthermore, in step 1, configuring the timer duration of the phase counting module based on the target phase includes:

[0032] If the period count value T is known, the relationship between the timer duration cnt and the target phase θ is cnt = (θ·T) / 360;

[0033] If the period count value T is unknown, the phase counting module performs period counting of the same phase square wave signal. After obtaining the period count value T, the timer duration cnt is calculated according to the formula cnt = (θ·T) / 360.

[0034] When the period of the sine wave is T and the target phase θ is 90 degrees, the timer duration cnt of the phase counting module is equal to T / 4.

[0035] Example 1

[0036] like Figure 1 As shown, the circuit includes a sinusoidal wave phase detection circuit composed of a DC blocking filter capacitor, a zero-crossing hysteresis comparator circuit, a level conversion circuit, and a phase counting circuit, wherein:

[0037] The output of the DC blocking filter capacitor is connected to the input of the zero-crossing hysteresis comparator;

[0038] The output of the zero-crossing hysteresis comparator is connected to the input of the level shifting circuit;

[0039] The output of the level conversion circuit is connected to the input of the phase counting circuit;

[0040] The sinusoidal input signal is input to the zero-crossing hysteresis comparator after passing through the DC blocking filter capacitor, which generates a square wave signal in phase with the sinusoidal input signal. The square wave signal in phase is then input to the phase counting module after passing through the level conversion circuit.

[0041] Preferably, the DC blocking filter capacitor includes a capacitor whose function is to filter out the DC component of the input signal;

[0042] Preferably, the threshold for the zero-crossing hysteresis comparator output signal to change from low to high is 0V, and the output is high when the input voltage is higher than 0V;

[0043] Preferably, the phase counting module is implemented based on an FPGA, and the phase counting module includes a timer, the timing duration of which can be configured according to the target phase.

[0044] The circuit's operating methods include:

[0045] Step 1: Configure the timer duration cnt of the phase counting module according to the target phase θ;

[0046] Step 2: The phase counting module starts the timer after detecting the rising edge of the in-phase square wave signal;

[0047] Step 3: When the timer of the phase counting module expires, it outputs a pulse signal to indicate the target phase.

[0048] Preferably, the timer duration for configuring the phase counting module according to the target phase in step 1 includes:

[0049] Given the period count value T, the relationship between the timer duration cnt and the target phase θ is cnt = (θ·T) / 360;

[0050] When the period count value T is unknown, the phase counting module first performs period counting of the same phase square wave signal to obtain the period count value T, and then calculates the timer duration cnt according to the formula cnt=(θ·T) / 360.

[0051] Example 2

[0052] like Figure 2 As shown, the present invention is applicable to sinusoidal wave phase detection scenarios with generalization requirements. Assuming the phase to be detected is θ, after detecting the phase θ, a single pulse signal is output to indicate the phase.

[0053] The sine wave phase detection circuit includes a DC blocking filter capacitor, a zero-crossing hysteresis comparator circuit, a level shifting circuit, and a phase counting circuit. The DC blocking filter capacitor includes a series capacitor used to filter out the DC component coupled to the input sine wave signal. The zero-crossing hysteresis comparator circuit generates a square wave signal in phase with the input sine wave signal. When the input sine wave changes from -0V to +0V, the output signal changes from low to high level. Simultaneously, the hysteresis loop filters out high-frequency glitches, improving anti-interference capability. The level shifting circuit matches the output level of the zero-crossing hysteresis comparator circuit with the input level of the phase counting circuit. If the two levels are the same, no level shifting circuit is needed. The phase counting circuit, implemented using an FPGA, is used to count the phases of the in-phase square wave signals. Given the period count value T of the sinusoidal signal, the timer duration cnt is calculated using the formula cnt = (θ·T) / 360, and cnt is configured into the FPGA-based phase counting module. After the input sinusoidal signal is input to the DC blocking filter capacitor and the zero-crossing hysteresis comparator, a square wave signal in phase with the input sinusoidal signal is generated. The phase counting module detects the rising edge of the square wave signal in phase and simultaneously starts the timer of the phase counting module. When the timer of the phase counting module expires, the phase counting module outputs a single pulse signal to indicate the target phase θ.

[0054] When the period count value T of the sinusoidal wave signal is unknown, the phase counting module first performs period counting of the square wave signal in the same phase to obtain the period count value T. Then, it calculates the timer duration cnt according to the formula cnt=(θ·T) / 360, configures cnt to the phase counting module based on FPGA, and then performs phase detection.

[0055] This invention inputs a DC-blocked filtered sine wave into a zero-crossing hysteresis comparator, generating a square wave signal in phase with the input sine wave. The rising edge of this in-phase square wave signal is detected to obtain the 0° phase point of the sine wave. A configurable timer is triggered at the 0° phase point, and when the timer expires, a pulse signal is generated to indicate the target phase point. This invention achieves effective sine wave phase detection, improves real-time performance, simplifies the hardware topology and software design of the sine wave peak sampling circuit, and reduces costs.

[0056] The product provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the invention claims.

Claims

1. A sinusoidal wave phase detection circuit, comprising a DC blocking filter capacitor, a level conversion circuit, and a phase counting circuit, characterized in that, It also includes a zero-crossing hysteresis comparator circuit, in which: The output of the DC blocking filter capacitor is connected to the input of the zero-crossing hysteresis comparator, the output of the zero-crossing hysteresis comparator is connected to the input of the level conversion circuit, and the output of the level conversion circuit is connected to the input of the phase counting circuit. The sinusoidal input signal is input to the zero-crossing hysteresis comparator after passing through the DC blocking filter capacitor, which generates a square wave signal in phase with the input sinusoidal signal. The square wave signal in phase is then input to the phase counting module after passing through the level conversion circuit. The working method of the sine wave phase detection circuit includes: Step 1: Based on the target phase Configure the timer duration cnt of the phase counting module, where, if the period count value T is known, the timer duration cnt is related to the target phase. The relationship is ; If the period count value T is unknown, the phase counting module performs period counting on the same-phase square wave signal, obtains the period count value T, and then follows the formula... Calculate the timer duration cnt; The period of the sine wave is T, and the target phase is... When the angle is 90 degrees, the timer duration cnt of the phase counting module is equal to T / 4; Step 2: After the phase counting module detects the rising edge of the in-phase square wave signal, it starts the timer. Step 3: When the timer of the phase counting module expires, it outputs a pulse signal to indicate the target phase.

2. The sinusoidal wave phase detection circuit according to claim 1, characterized in that, The DC blocking filter capacitor can filter out the DC component of the input signal.

3. The sinusoidal wave phase detection circuit according to claim 1, characterized in that, The zero-crossing hysteresis comparator circuit is also used to change the output signal from low level to high level when the input sine wave changes from -0V to +0V. At the same time, the hysteresis loop can filter out high-frequency glitches and improve anti-interference capability.

4. The sinusoidal phase detection circuit according to claim 3, characterized in that, The zero-crossing hysteresis comparator circuit includes resistors R1, R2, and R3, and an operational amplifier, wherein: One end of resistor R1 is grounded, and the other end is connected to the positive input terminal of the operational amplifier and one end of resistor R2. The other end of resistor R2 is connected to the output terminal of the operational amplifier and one end of resistor R3. The other end of resistor R3 is a DC power supply. The inverting input of the operational amplifier is connected to the input of the DC blocking filter capacitor, and the output is connected to the level conversion circuit.

5. The sinusoidal wave phase detection circuit according to claim 1, characterized in that, The phase counting module is implemented based on an FPGA and includes a timer, the duration of which is configured according to the target phase.

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