Improved voltage sampling circuit
By increasing the ground -dividing resistor to the voltage sampling circuit of the inverter, the problem of inaccurate samples caused by the non -isolation of the control circuit and the power circuit ground is solved, and higher sampling accuracy and the safe and efficient operation of the inverter.
Patent Information
- Application Number
- CN202421017372.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-11
- Publication Date
- 2025-01-28
- Estimated Expiration
- 2034-05-11
AI Technical Summary
The existing differential sampling circuit is not isolated from the control circuit and the power circuit in the inverter, resulting in inaccurate sampling, large errors, and inability to work normally.
On the basis of the original difference sampling circuit, increase the ground pressure resistance, so that the DC voltage of the power circuit cannot enter the control circuit, thereby improving the sampling accuracy.
Effectively improve the sampling accuracy, avoid the problem of inaccurate sampling, and enable the inverter to work safer and efficiently.
Smart Images
Figure CN222423663U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a voltage sampling feedback technology, and in particular to an improved voltage sampling circuit in a voltage sampling in an inverter. Background Art
[0002] An inverter is a power supply device that can convert the direct current of a battery into alternating current for use by the load. Due to its high efficiency and convenience, it has been widely used. Currently, inverters are widely used in special vehicles, offices, communication rooms and other places, bringing great convenience to users.
[0003] When the inverter is working, the output voltage needs to be sampled and then fed back to the microprocessor. Most of the output voltage sampling now uses a differential sampling circuit. However, the commonly used differential sampling circuit can only be used when the ground of the control circuit and the ground of the power circuit are isolated. But now the ground of the control circuit and the ground of the power circuit of some inverters are not isolated. In this case, using the original differential sampling circuit will cause inaccurate sampling and large errors, making the inverter unable to work normally, so the existing voltage sampling needs further improvement. Utility Model Content
[0004] In order to solve one of the above-mentioned technical defects, an improved voltage sampling circuit is provided in the embodiment of the present application, which can well solve this problem. On the basis of the original differential sampling circuit, the circuit adds a grounding voltage divider resistor, so that the DC voltage of the power loop cannot enter the control circuit, thereby effectively improving the sampling accuracy, avoiding the occurrence of the above-mentioned problems, and enabling the inverter to work more safely and efficiently.
[0005] According to a first aspect of an embodiment of the present application, an improved voltage sampling circuit is provided, comprising: an operational amplifier U2B, wherein the positive input terminal 5 pin of the operational amplifier U2B is connected to resistors R35, R37, R39 and R41, wherein the resistors R35, R37, R39 and R41 are connected in series and connected to the positive end of the sampled circuit, and the negative input terminal 6 pin of the operational amplifier U2B is connected to resistors R36, R38, R40 and R42, wherein the resistors R36, R38, R40 and R42 are connected in series and connected to the negative end of the sampled circuit.
[0006] Furthermore, the positive input terminal 5 pin of the operational amplifier U2B is connected to the 2.5V voltage through the resistor R33 and the capacitor C3, and the R33 and the capacitor C3 are connected in parallel.
[0007] Furthermore, the inverting input terminal 6 pin of the operational amplifier U2B is connected to the output terminal 7 pin of the operational amplifier U2B through a resistor R34 and a capacitor C9, and the resistor R34 and the capacitor C9 are connected in parallel.
[0008] Furthermore, the output terminal 7 pin of the operational amplifier U2B is connected to the output sampling terminal through the resistor R27, and the output sampling terminal is connected to the ground through the capacitor C4.
[0009] Furthermore, the positive input terminal pin 5 of the operational amplifier is connected to the ground through the resistor R11, and the negative input terminal pin 6 of the operational amplifier U2B is connected to the ground through the resistor R22.
[0010] Furthermore, the operating value of resistors R35, R37, R39, R41, R36, R38, R40 and R42 is 665 kΩ.
[0011] An improved voltage sampling circuit provided in an embodiment of the present application is adopted. On the basis of the original differential sampling circuit, the circuit adds a grounding voltage divider resistor, so that the DC voltage of the power loop cannot enter the control circuit, thereby effectively improving the sampling accuracy, avoiding the occurrence of the above-mentioned problems, and enabling the inverter to work more safely and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0013] Figure 1 A schematic diagram of the structure of an improved voltage sampling circuit provided in an embodiment of the present application. DETAILED DESCRIPTION
[0014] In order to make the technical solutions and advantages in the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0015] The utility model discloses an improved voltage sampling circuit, which is used to adopt the output voltage of the inverter. Figure 1As shown, the improved voltage sampling circuit includes an operational amplifier U2B, resistors R11, R22, R27, R33, R34, R35, R36, R37, R38, R39, R40, R41, R42, and capacitors C3, C4, and C9. Among them, pin 5 of the operational amplifier U2B is connected to the positive end of the sampled circuit through resistors R35, R37, R39, and R41, pin 5 of the operational amplifier U2B is connected to a 2.5V voltage through resistor R33 and capacitor C3, pin 6 of the operational amplifier U2B is connected to the negative end of the sampled circuit through resistors R36, R38, R40, and R42, pin 6 of the operational amplifier U2B is connected to pin 7 of the operational amplifier U2B through resistor R34 and capacitor C9, pin 7 of the operational amplifier U2B is connected to the "output sampling" end of the sampling circuit through resistor R27, and the "output sampling" end is connected to ground through capacitor C4. At the same time, pin 5 of the operational amplifier U2B is connected to ground through resistor R11, and pin 6 of the operational amplifier U2B is connected to ground through resistor R22.
[0016] Figure 1 FIG. 1 is an application diagram of an improved voltage sampling circuit of the utility model. Figure 1 As shown, in this embodiment, the improved voltage sampling circuit is used to perform feedback regulation on the output voltage of the inverter. Figure 1 Connect the "OUT-L" terminal in the inverter to the "OUT-L" terminal of the inverter output. Figure 1 The "OUT-N" terminal in the circuit is connected to the "OUT-N" terminal of the inverter output terminal, and the "output sampling" terminal is connected to the microprocessor. After the inverter works, the output AC voltage will be added to the 5th and 6th pins of the operational amplifier U2B through resistors R35, R36, R37, R38, R39, R40, R41, and R42. The 7th pin of the operational amplifier U2B will generate a corresponding sampling voltage, which will be output to the microprocessor through the "output sampling" after passing through the filtering circuit composed of resistor R27 and capacitor C4. The microprocessor uses this voltage to determine the output voltage size. If it is a non-isolated inverter, the DC voltage will pass through resistors R36, R38, R40, R42, R34, and R27 from the "OUT-N" terminal to the output terminal, so that the output sampling voltage is superimposed on this DC voltage, which makes the sampling voltage deviation larger and cannot be used normally. For this reason, Figure 1 Grounding resistors R11 and R22 are added to the circuit and connected to pins 5 and 6 of the operational amplifier U2B respectively. In this way, the DC voltage will be divided at pins 5 and 6 of the operational amplifier U2B. Since the resistance values of resistors R35, R36, R37, R38, R39, R40, R41, and R42 are much larger than those of R11 and R22, the influence of the DC voltage can be eliminated, so that the inverter can work normally.
[0017] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.
[0018] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.
Claims
1. An improved voltage sampling circuit, characterized in that: include: An operational amplifier U2B, wherein the positive input terminal 5 pin of the operational amplifier U2B is connected to resistors R35, R37, R39 and R41, which are connected in series and connected to the positive end of the sampled circuit, and the negative input terminal 6 pin of the operational amplifier U2B is connected to resistors R36, R38, R40 and R42, which are connected in series and connected to the negative end of the sampled circuit.
2. The improved voltage sampling circuit according to claim 1, characterized in that: The positive input terminal 5 pin of the operational amplifier U2B is connected to the 2.5V voltage through the resistor R33 and the capacitor C3, and the resistor R33 and the capacitor C3 are connected in parallel.
3. The improved voltage sampling circuit according to claim 1, characterized in that: The inverting input terminal 6 pin of the operational amplifier U2B is connected to the output terminal 7 pin of the operational amplifier U2B through a resistor R34 and a capacitor C9, and the resistor R34 and the capacitor C9 are connected in parallel.
4. The improved voltage sampling circuit according to claim 1, characterized in that: The output terminal 7 pin of the operational amplifier U2B is connected to the output sampling terminal through a resistor R27, and the output sampling terminal is connected to the ground through a capacitor C4.
5. The improved voltage sampling circuit according to claim 3, characterized in that: The positive input terminal pin 5 of the operational amplifier is connected to the ground through the resistor R11, and the negative input terminal pin 6 of the operational amplifier U2B is connected to the ground through the resistor R22.
6. The improved voltage sampling circuit according to claim 3, characterized in that: The resistors R35, R37, R39, R41, R36, R38, R40 and R42 are all 665 kΩ.