A full electronic on-board transformer phase difference measuring circuit

Abstract

The utility model belongs to a kind of measurement circuit of full electronic board transformer phase difference, comprising: the alternating current power supply of providing primary voltage to transformer, the direct current power supply of power supply for digital circuit, primary sampling circuit, secondary sampling circuit, filter circuit, analog multiplier, processor and display. The alternating current power supply provides voltage to transformer primary, by primary sampling circuit and secondary sampling circuit, the primary and secondary voltage of transformer is sent into the input end of analog multiplier after filtering by filter circuit, the output signal is sent to processor, analog signal is converted into digital signal, and the amplitude of positive and negative half wave of comparison signal is passed through, the phase difference of primary and secondary is accurately calculated, to show in display in the form of number, to be able to accurately measure the phase of transformer in full electronic interlocking circuit board, improve the yield of product batch production.

Description

Technical Field

[0001] This utility model relates to the measurement technology of transformer phase difference in the field of rail transit, and in particular to a measurement circuit for phase difference of a fully electronic on-board transformer. Background Technology

[0002] With the continuous improvement of railway automation, fully electronic interlocking systems will be comprehensively applied to the railway system. Various transformers (track transformers, turnout indicator transformers, etc.) originally used in centralized electrical interlocking will be miniaturized and integrated into fully electronic circuit boards, serving as core components in various modules. The performance parameters of these transformers directly affect whether the fully electronic interlocking system can accurately acquire turnout position information and track status information, especially the transformers used in phase-sensitive track circuits, which have very high requirements for phase accuracy.

[0003] Currently, there is no corresponding method for measuring the phase of onboard transformers. The overall function of the board can only be tested after it is soldered onto the circuit board, but it is impossible to accurately measure the phase of the transformer itself or the overall phase after combining it with the corresponding resistor-capacitor circuit. Utility Model Content

[0004] The purpose of this invention is to provide a measurement circuit for the phase difference of an all-electronic onboard transformer, so as to accurately measure the phase difference between the primary and secondary voltages of the onboard transformer, improve the yield rate during board production, and provide an important guarantee for the stable operation of the product.

[0005] The technical solution of this utility model is: a phase difference measurement circuit for a fully electronic onboard transformer, comprising: an AC power supply providing primary voltage to the transformer, a DC power supply supplying power to the digital circuit, a primary sampling circuit, a secondary sampling circuit, a filtering circuit, an analog multiplier, an AC signal amplitude detection circuit, and a display device. The AC power supply provides voltage to the primary winding of the transformer. The sampling circuit filters the primary and secondary voltages of the transformer through the filtering circuit and sends them to the input terminal of the analog multiplier. The signal output by the analog multiplier is sent to the AC signal amplitude detection circuit. The AC signal amplitude detection circuit has a processor with a 16-bit A / D converter, which converts the analog signal into a digital signal and calculates and displays the phase difference between the primary and secondary windings by comparing the amplitudes of the positive and negative half-waves of the signal.

[0006] The frequency and voltage of the AC power supply are selected based on the actual application of the transformer. The DC power supply uses a DC 5V power module.

[0007] The primary and secondary sampling circuits each consist of two series resistors. Utilizing the principle of voltage division within the series resistors, an AC signal with the same frequency, phase, and amplitude of 1V is obtained, identical to the sampled voltage. To avoid the influence of subsequent filtering circuits on voltage acquisition, the current through the sampling series resistors should not be less than 0.1A, and the resistor accuracy should not exceed 0.5%.

[0008] The filtering circuit is used to filter out interference from the environment and surrounding devices, preventing interference from entering the analog multiplier.

[0009] The analog multiplier described uses a high-precision four-quadrant analog multiplier to convert the signals from the primary and secondary windings of the transformer into AC signals with twice the frequency and amplitude that varies with the phase difference between the primary and secondary windings of the transformer.

[0010] The AC signal amplitude detection circuit can use an ADSP-21489 processor to filter the sampled data through an algorithm, then read the amplitude of the positive and negative half-waves of each cycle and sum them, then average the values ​​of the 5 cycles, and finally perform arcsine calculation to obtain the phase difference between the primary and secondary signals of the transformer.

[0011] The advantages of this invention are: by converting the phase difference between the primary and secondary voltages of the transformer into the difference in amplitude of the positive and negative half-waves of the AC signal, and finally by accurately calculating and detecting the phase difference between the primary and secondary voltages of the transformer by detecting the difference in the peak values ​​of the positive and negative half-wave voltages, the yield rate of the circuit board is improved, and an important guarantee is provided for the stable operation of the product. Attached Figure Description

[0012] Figure 1 This is the circuit schematic diagram of this utility model;

[0013] Figure 2 This is the circuit schematic diagram of Embodiment 1 of this utility model;

[0014] Figure 3 This is the circuit schematic diagram of Embodiment 2 of this utility model;

[0015] Figure 4 This is a schematic diagram of the AC signal amplitude detection circuit in Example 2.

[0016] In the diagram: 1. AC power supply; 2. DC power supply; 3. Primary voltage sampling circuit; 4. Secondary voltage sampling circuit; 5. Filter circuit; 6. Analog multiplier; 7. AC signal amplitude detection circuit; 8. Display device; 9. Reference power supply; 10. Rectifier circuit; 11. Comparator circuit; 12. Amplifier circuit. Detailed Implementation

[0017] To further illustrate the technical means and effects of this utility model in achieving its intended purpose, the specific implementation methods, structural features and effects of this utility model are described in detail below with reference to the accompanying drawings and embodiments.

[0018] like Figure 1 As shown, this utility model relates to a phase difference measurement circuit for an all-electronic onboard transformer, comprising: an AC power supply 1 providing primary voltage to the transformer, a DC power supply 2 providing power to the digital circuit, a primary sampling circuit 3, a secondary sampling circuit 4, a filtering circuit 5, an analog multiplier 6, an AC signal amplitude detection circuit 7, and a display 8. The AC power supply 1 provides voltage to the primary winding of the transformer. The primary and secondary voltages of the transformer are filtered by the primary sampling circuit 3 and the secondary sampling circuit 4 and then fed into the input terminal of the analog multiplier 6. The signal output by the analog multiplier is sampled by the AC signal amplitude detection circuit 7, converting the analog signal into a digital signal. By comparing the amplitudes of the positive and negative half-waves of the signal, the phase difference between the primary and secondary windings is calculated and displayed digitally on the display 8.

[0019] This utility model provides two embodiments to illustrate the concept of this utility model. Example 1

[0020] like Figure 2 As shown, AC power supply 1 provides voltage to the primary winding of the transformer. The primary and secondary voltages of the transformer are filtered by primary sampling circuit 3 and secondary sampling circuit 4, and then fed into the input terminal of analog multiplier 6 after filtering by filter circuit 5. The signal output by analog multiplier is sampled by AC signal amplitude detection circuit 7. The AC signal amplitude detection circuit 7 is a processor with 16-bit A / D, such as ADSP-21489. First, the analog signal is converted into a digital signal by sampling. The sampled data is filtered by an algorithm. Then, the amplitude of the positive and negative half-waves of each cycle is read and summed. The values ​​of the five cycles are then averaged to obtain the final difference between the positive and negative half-wave amplitudes. Finally, an arcsine operation is performed to obtain the accurate phase difference between the primary and secondary signals of the transformer, which is displayed digitally on display 8.

[0021] The AC power supply 1 selects its frequency and voltage value according to the actual application of the transformer. The DC power supply 2 uses a DC 5V power module. The primary sampling circuit 3 and the secondary sampling circuit 4 each consist of two series resistors, employing the principle of voltage division by series resistors to obtain an AC signal with the same frequency, phase, and amplitude of 1V as the sampled voltage. To avoid the influence of the subsequent filtering circuit 5 on voltage acquisition, the current of the sampling resistor should not be less than 0.1A, and the resistor accuracy should not be greater than 0.5%. The filtering circuit 5 is used to filter out interference from the environment and surrounding devices. The analog multiplier 6 uses an MPY634U to convert the signals from the primary and secondary windings of the transformer into AC signals with twice the frequency and amplitude varying with the phase difference. Example 2

[0022] like Figure 3 As shown, AC power supply 1 provides voltage to the primary winding of the transformer. The primary and secondary voltages of the transformer are filtered by primary sampling circuit 3 and secondary sampling circuit 4, and then fed into the input terminal of analog multiplier 6. The output signal is sent to AC signal amplitude detection circuit 7. This detection circuit compares the amplitude of the positive and negative half-waves of the AC signal with a reference source to determine whether both reach a set threshold. If they do, the indicator light is turned on; otherwise, it is turned off. This determines whether the phase difference between the primary and secondary windings of the transformer is within a set range.

[0023] The AC power supply 1, DC power supply 2, primary sampling circuit 3, secondary sampling circuit 4, and filter circuit 5 are the same as in Embodiment 1. The analog multiplier 6 uses a variable transconductance analog multiplier to convert the signals from the primary and secondary windings of the transformer into AC signals with twice the frequency and amplitude varying with the phase difference.

[0024] like Figure 4 As shown, the AC signal amplitude detection circuit 7 includes: a reference power supply 9, a rectifier circuit 10, a comparator circuit 11, and an amplifier circuit 12. The AC signal output from the analog multiplier 6 is rectified by the rectifier circuit 10 into positive and negative half-waves respectively, and then compared with the reference power supply 9 by the comparator circuit 11 to detect whether the voltage amplitude reaches the set threshold. Its output is a switching signal, which is amplified by the amplifier circuit 12 to drive the indicator lights. If both indicator lights are lit simultaneously, it indicates that the amplitude of the AC signal meets the requirements, thus determining that the phase difference between the primary and secondary windings of the transformer is within the set value.

[0025] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. A circuit for measuring the phase difference of a fully electronic onboard transformer, characterized in that: include: The system includes an AC power supply providing primary voltage to the transformer, a DC power supply supplying power to the digital circuit, a primary sampling circuit, a secondary sampling circuit, a filtering circuit, an analog multiplier, an AC signal amplitude detection circuit, and a display. The AC power supply provides voltage to the primary winding of the transformer. The primary and secondary voltages of the transformer are filtered by the primary and secondary sampling circuits and then fed into the input of the analog multiplier. The signal output by the analog multiplier is processed by the AC signal amplitude detection circuit, which converts the analog signal into a digital signal. The phase difference between the primary and secondary windings is calculated and displayed by comparing the amplitudes of the positive and negative half-waves of the signal.

2. The all-electronic on-board transformer phase difference measurement circuit according to claim 1, characterized in that: The primary sampling circuit and the secondary sampling circuit are each composed of two series resistors. The series resistors are used to divide the voltage to obtain an AC signal with the same frequency and phase as the sampled voltage and an amplitude of 1V.

3. The all-electronic on-board transformer phase difference measurement circuit according to claim 2, characterized in that: The current passing through the series resistor should not be less than 0.1A, and the accuracy of the series resistor should not be greater than 0.5%.

4. The phase difference measurement circuit of a fully electronic on-board transformer according to claim 1, characterized in that: The DC power supply used is a DC 5V power module.

5. The phase difference measurement circuit of a fully electronic on-board transformer according to claim 1, characterized in that: The filtering circuit is used to filter out interference from the environment and surrounding devices, preventing interference from entering the analog multiplier.

6. The phase difference measurement circuit of a fully electronic on-board transformer according to claim 1, characterized in that: The analog multiplier converts the signals from the primary and secondary windings of the transformer into AC signals with twice the frequency and amplitude that varies with the phase difference between the primary and secondary windings of the transformer.

7. The phase difference measurement circuit of a fully electronic on-board transformer according to claim 1, characterized in that: The analog multiplier is a variable transconductance analog multiplier, which converts the signals from the primary and secondary windings of the transformer into AC signals with twice the frequency and whose amplitude varies with the phase difference between the primary and secondary windings of the transformer.

8. The phase difference measurement circuit of a fully electronic on-board transformer according to claim 1, characterized in that: The AC signal amplitude detection circuit is a processor, specifically a processor with a 16-bit A / D converter, specifically an ADSP-21489.

9. The phase difference measurement circuit of a fully electronic on-board transformer according to claim 1, characterized in that: The AC signal amplitude detection circuit includes: a reference power supply, a rectifier circuit, a comparator circuit, and an amplifier circuit. The AC signal output from the analog multiplier is rectified by the rectifier circuit to produce the positive and negative half-waves respectively. Then, the comparator circuit compares it with the reference power supply to detect whether the positive or negative voltage reaches the set threshold. Its output is a switching quantity, which is amplified by the amplifier circuit to drive the indicator light. The illumination status of the indicator light reflects whether the amplitude of the AC signal meets the requirements, thereby determining that the phase difference between the primary and secondary windings of the transformer is within the set value.

Images