CN213600779U - Zero crossing point detection circuit for direct current motor - Google Patents
Zero crossing point detection circuit for direct current motor Download PDFInfo
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- CN213600779U CN213600779U CN202022247043.3U CN202022247043U CN213600779U CN 213600779 U CN213600779 U CN 213600779U CN 202022247043 U CN202022247043 U CN 202022247043U CN 213600779 U CN213600779 U CN 213600779U
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Abstract
The utility model provides a zero crossing point detection circuit for a direct current motor, which comprises a rectifier bridge, a first resistor, a second resistor, a third resistor, a voltage stabilizing diode and a filter capacitor; the first resistor, the second resistor and the third resistor are sequentially connected in series, the first end of the first resistor is connected with the second input end of the rectifier bridge, and the second end of the third resistor is connected with the second output end of the rectifier bridge; the third resistor is respectively connected with the voltage stabilizing diode and the filter capacitor in parallel, wherein the cathode of the voltage stabilizing diode is connected between the second resistor and the third resistor, the anode of the voltage stabilizing diode is connected with the second end of the third resistor, and the second end of the third resistor is grounded. Step down, the rectification through the transformer in with traditional circuit, the switch of rethread triode produces the zero signal and compares, the utility model discloses the circuit is simpler, and is with low costs.
Description
Technical Field
The utility model belongs to zero crossing point detection area especially relates to a zero crossing point detection circuitry for direct current motor.
Background
In an electric tool applied to a garden, it is generally necessary to change an input voltage of a dc motor by a Pulse Width Modulation (PWM) method, so as to control a rotation speed of the dc motor. In PWM modulation, it is usually necessary to continue to detect the zero crossing of the alternating current, and when the waveform is switched from the positive half cycle to the negative half cycle, the zero crossing is detected when the waveform passes through the zero position, i.e. when the voltage amplitude is zero. In a conventional zero crossing point detection circuit, after alternating current is rectified into direct current, the direct current is compared with conduction voltage of a triode, a pulse waveform is formed by utilizing the conduction and cut-off characteristics of the triode, and a zero crossing point of the voltage is judged according to the formed pulse waveform.
The traditional zero crossing point circuit adopts more optical couplers, triodes and other elements to detect the zero crossing point, the circuit structure is complex, the number of elements is large, the cost is high, and the heating is easy to cause.
SUMMERY OF THE UTILITY MODEL
In order to solve the defects and deficiencies in the prior art, the utility model provides a zero crossing point detection circuit for a direct current motor, which comprises a rectifier bridge, a first resistor, a second resistor, a third resistor, a voltage stabilizing diode and a filter capacitor;
the rectifier bridge comprises a first input end connected with the live wire, a second input end connected with the zero line, a first output end used as a positive electrode output, and a second output end used as a negative electrode output;
the first resistor, the second resistor and the third resistor are sequentially connected in series, the first end of the first resistor is connected with the second input end of the rectifier bridge, and the second end of the third resistor is connected with the second output end of the rectifier bridge;
the third resistor is respectively connected with the voltage stabilizing diode and the filter capacitor in parallel, wherein the cathode of the voltage stabilizing diode is connected between the second resistor and the third resistor, the anode of the voltage stabilizing diode is connected with the second end of the third resistor, and the second end of the third resistor is grounded.
Optionally, the resistances of the first resistor, the second resistor, and the third resistor are all 100k Ω.
Optionally, the regulated voltage of the zener diode is 5.1V.
Optionally, the capacitance value of the filter capacitor is 100 pF.
Optionally, a negative electrode of the zener diode generates a zero crossing point detection signal.
Optionally, the zero crossing point detection circuit further includes a fuse, and the fuse is connected between the live wire and the first input end of the rectifier bridge.
The utility model provides a beneficial effect that technical scheme brought is:
step down, the rectification through the transformer in with traditional circuit, the switch of rethread triode produces the zero signal and compares, the utility model discloses the circuit is simpler, and is with low costs, has reduced element quantity.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a conventional zero-crossing point detection circuit diagram;
fig. 2 is the utility model provides a zero crossing point detection circuit diagram for dc motor.
Detailed Description
In order to make the structure and advantages of the present invention clearer, the structure of the present invention will be further described with reference to the accompanying drawings.
Example one
As shown in fig. 1, a common zero-crossing point detection circuit diagram is formed by connecting a cathode of a diode D1 to a 12V power supply through isolation of a transformer T1, and performing full-wave rectification on alternating current through a rectifier bridge formed by a diode D1, a diode D2, a diode D3, and a diode D4, a diode D5, and a diode D6 to form a pulsating direct current waveform. Voltage is divided by a resistor R1, a resistor R2 and a resistor R3, then the voltage is filtered by a filter capacitor C1, high-frequency parts are filtered, and a voltage waveform is formed at a point C. When the voltage of the point C is more than 0.7V, the triode Q2 is conducted, and a low level is formed at the collector of the triode; when the voltage of the point C is lower than 0.7V, the triode is cut off, and the collector of the triode forms a high level through a pull-up resistor R4 connected with a 5V power supply. Therefore, through the repeated conduction and cut-off of the triode, a pulse waveform is formed at the D point of the chip detection port, and the chip judges the zero crossing point of the detection voltage.
The circuit uses many elements such as diodes and resistors, and has a complicated circuit structure, and the elements consume excessive power, which is likely to generate heat. In addition, the circuit realizes the function of detecting the zero crossing point by utilizing the conduction characteristic of the triode, but due to the conduction characteristic of the triode, the triode is conducted when the conduction voltage is reached, and the conduction rising edge time of the triode is longer, so that the zero crossing point indicated by the zero crossing point detection circuit lags behind the actual zero crossing point.
Based on the above defect, the utility model provides a zero crossing detection circuitry for motor, as shown in FIG. 2, including rectifier bridge D18, first resistance R1, second resistance R2, third resistance R3, zener diode D1, filter capacitor C1 and fuse F1.
The rectifier bridge D18 comprises a first input end connected with a live wire ACL, a second input end connected with a zero wire ACN, a first output end serving as a positive electrode output, and a second output end serving as a negative electrode output;
the first resistor R1, the second resistor R2 and the third resistor R3 are sequentially connected in series, the first end of the first resistor R1 is connected with the second input end of the rectifier bridge D18, and the second end of the third resistor R3 is connected with the second output end of the rectifier bridge D18;
the third resistor R3 is respectively connected in parallel with the zener diode D1 and the filter capacitor C1, wherein the cathode of the zener diode D1 is connected between the second resistor R2 and the third resistor R3, the anode of the zener diode D1 is connected to the second end of the third resistor R3, and the second end of the third resistor R3 is grounded. Meanwhile, the cathode of the voltage stabilizing diode D1 outputs a zero crossing point detection signal through an IO pin connected with the controller.
When the alternating current is in a forward waveform, a forward voltage is formed through the rectifier bridge D18, the voltage across the third resistor R3 is stabilized at 5.1V through the voltage stabilizing diode D1, and when the alternating current is in a reverse waveform, the alternating current is cut off by the rectifier bridge D18, and the voltage across the third resistor R3 is 0. According to the repeated on and off of the voltage stabilizing diode D1, a zero crossing point detection signal is generated through the cathode of the voltage stabilizing diode D1, and an IO pin of the controller is connected with the cathode of the voltage stabilizing diode D1 and used for receiving the zero crossing point detection signal.
Compared with a common zero crossing point detection circuit, the triode is replaced by the voltage stabilizing diode, the conduction voltage of the triode is 0.7V generally, and due to the characteristics of the voltage stabilizing diode, as long as alternating current is forward voltage, the voltage stabilizing diode is conducted, meanwhile, the voltage can be stabilized at a certain value, the accuracy of zero crossing point detection is improved, the output zero crossing point detection signal is more stable, and the controller is favorable for receiving the accurate zero crossing point detection signal.
Compared with the circuit shown in fig. 1, the utility model provides a zero crossing point detection circuit uses few components, can effectively reduce the problem that the component generates heat, avoids other component power consumptions. With the circuit shown in fig. 1 show step down, the rectification through the transformer, the switch of rethread triode produces zero signal and compares, the utility model discloses the circuit is simpler, and is with low costs.
In addition, the zero crossing point of the alternating current is detected by utilizing the unidirectional conduction and voltage stabilization characteristics of the voltage stabilization diode, the forward conduction voltage is reduced, the limitation caused by the conduction voltage is overcome compared with a triode, and the accuracy of zero crossing point detection is improved. Meanwhile, the voltage stabilizing characteristic of the voltage stabilizing diode is utilized, stable signal level can be provided, external interference is not easy to cause, the generated zero crossing point detection signal is more stable, and the reliability of the zero crossing point detection circuit is improved.
In this embodiment, the resistances of the first resistor R1, the second resistor R2, and the third resistor R3 are all 100k Ω, the regulated voltage of the zener diode is 5.1V, and the capacitance of the filter capacitor is 100 pF.
The zero crossing point detection circuit further comprises a fuse, wherein the fuse is connected between the live wire and the first input end of the rectifier bridge, so that the current is prevented from being too high, and the function of protecting the circuit is achieved.
The sequence numbers in the above embodiments are merely for description, and do not represent the sequence of the assembly or the use of the components.
The above description is only an embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.
Claims (6)
1. The utility model provides a zero crossing detection circuitry for direct current motor which characterized in that, includes rectifier bridge, first resistance, second resistance, third resistance, zener diode and filter capacitance:
the rectifier bridge comprises a first input end connected with the live wire, a second input end connected with the zero line, a first output end used as a positive electrode output, and a second output end used as a negative electrode output;
the first resistor, the second resistor and the third resistor are sequentially connected in series, the first end of the first resistor is connected with the second input end of the rectifier bridge, and the second end of the third resistor is connected with the second output end of the rectifier bridge;
the third resistor is respectively connected with the voltage stabilizing diode and the filter capacitor in parallel, wherein the cathode of the voltage stabilizing diode is connected between the second resistor and the third resistor, the anode of the voltage stabilizing diode is connected with the second end of the third resistor, and the second end of the third resistor is grounded.
2. The zero-crossing detection circuit for the direct current motor according to claim 1, wherein the first resistor, the second resistor, and the third resistor each have a resistance of 100k Ω.
3. The zero-crossing detection circuit for a direct current motor according to claim 1, wherein the zener diode has a zener voltage of 5.1V.
4. A zero-crossing detection circuit for a dc motor according to claim 1, wherein the capacitance value of the filter capacitor is 100 pF.
5. The zero-crossing detection circuit for a dc motor according to claim 1, wherein a negative pole of the zener diode generates a zero-crossing detection signal.
6. A zero-crossing detection circuit for a dc motor according to claim 1, further comprising a fuse connected between the live line and the first input of the rectifier bridge.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022247043.3U CN213600779U (en) | 2020-10-10 | 2020-10-10 | Zero crossing point detection circuit for direct current motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022247043.3U CN213600779U (en) | 2020-10-10 | 2020-10-10 | Zero crossing point detection circuit for direct current motor |
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| Publication Number | Publication Date |
|---|---|
| CN213600779U true CN213600779U (en) | 2021-07-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022247043.3U Active CN213600779U (en) | 2020-10-10 | 2020-10-10 | Zero crossing point detection circuit for direct current motor |
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|---|---|
| CN (1) | CN213600779U (en) |
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- 2020-10-10 CN CN202022247043.3U patent/CN213600779U/en active Active
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