DC power supply feedback loop detection system

Abstract

The invention discloses a detection system for a power supply feedback loop of a direct-current power supply. The detection system comprises an isolation operational amplifier U2 and an isolation operational amplifier U3, wherein the isolation operational amplifier U2 and the isolation operational amplifier U3 form a redundant circuit for direct-current voltage detection; the input end of the isolation operational amplifier U2 and the input end of the isolation operational amplifier U3 are respectively connected with a bus voltage measuring point V through a corresponding S1 signal line and a corresponding S2 signal line; the invention has the beneficial effect of solving the problem of output overvoltage or instability of the digital power supply caused by the abnormality of the feedback loop of the power supply system.

Description

Technical Field

[0001] The invention relates to the technical field of digital power supplies, and in particular to a direct current power supply feedback loop detection system. Background Art

[0002] In some special equipment power supply requirements of higher reliability occasions, the digital power supply output by detecting the output voltage / current to control the output voltage of the controller power supply.

[0003] If the circuit in the feedback loop of the voltage detection is disconnected due to a fault, since the system uses negative feedback, the feedback signal is detected to be 0V (disconnection moment), causing the output voltage to be higher than the target setting voltage and damaging the subsequent power supply equipment. The current technical means used for the output of digital power supplies is that when the external feedback loop detects an abnormal output voltage, the software limits the maximum output amplitude and the DC output is connected to an overvoltage protection device circuit.

[0004] The problem of overvoltage or instability of the digital power supply output caused by abnormal feedback loops and the problem of inability to effectively detect before voltage is built up during the power-on initialization phase of the control system are not considered. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art; to this end, the present invention proposes a DC power supply feedback loop detection system, which is used to solve the technical problem that the prior art does not consider the feedback loop abnormality causing digital power supply output overvoltage or instability.

[0006] To achieve the above object, the present invention provides a DC power supply feedback loop detection system, comprising: an isolation amplifier U2 and an isolation amplifier U3 form a redundant circuit for DC voltage detection;

[0007] The input end of the isolation amplifier U2 and the input end of the isolation amplifier U3 are connected to the bus voltage measurement point V through corresponding S1 signal lines and S2 signal lines respectively.

[0008] Furthermore: the isolation amplifier U2 and the isolation amplifier U3 are voltage detection isolation amplifiers with the same structure;

[0009] The voltage detection isolation amplifier comprises: a plurality of resistors, an isolation amplifier, and an operational amplifier;

[0010] The input end of the isolation amplifier is connected to the bus voltage measurement point V, i.e., the bus input;

[0011] The isolation amplifier outputs a differential voltage signal, and the isolation amplifier is connected to the in-phase input terminal and the reverse input terminal of the operational amplifier through two differential lines, and at least one resistor is set on each of the two differential lines between the isolation amplifier and the operational amplifier;

[0012] The calculation method device is also connected in parallel with at least one resistor;

[0013] The output end of the operational amplifier is connected to the AD pin of the MCU chip.

[0014] Furthermore: the isolation amplifier U2 and the isolation amplifier U3 form a redundant circuit for DC voltage detection, and the MCU chip simultaneously judges the DC power supply detected by the isolation amplifier U2 and the isolation amplifier U3 in the redundant circuit;

[0015] When the S1 signal line corresponding to the isolation amplifier U2 is broken, it means that the output of the isolation amplifier U2 is 0V, and the bus voltage cannot be detected normally; at this time, the detection of the isolation amplifier U3 is switched, the control loop PI outputs normally, and the MCU chip issues an S1 signal line broken alarm fault instruction;

[0016] When the S2 signal line corresponding to the isolation amplifier U3 is broken, it means that the output of the isolation amplifier U3 is 0V and the bus voltage cannot be detected normally. At this time, the detection of the isolation amplifier U2 is switched, the control loop PI outputs normally, and the MCU chip issues an S2 signal line break alarm fault instruction.

[0017] Furthermore: the thresholds set for the window comparator U4 and the window comparator U5 are both ±20% of the target voltage value. When a short line or overvoltage occurs in any window comparator, the output level of the window comparator is reversed, and the output signal is sent to the INT pin of the MCU chip through the U6 or gate to achieve the purpose of outputting an interrupt signal to notify an external interrupt.

[0018] Further: the bus voltage measurement point V is also connected to the diode D1, the DC / DC power module U7 and the EN pin of the MCU chip in sequence;

[0019] The diode D1 and the DC / DC power supply module U7 form a power-on disconnection diagnosis circuit;

[0020] The diode D1 is a backflow prevention device, and the bus voltage measurement point V is connected to the cathode of the diode D1.

[0021] Furthermore: the DC / DC power supply module U7 is specifically an isolated power supply, and provides a 24V voltage to flow to the bus voltage measurement point V through the diode D1.

[0022] Further: the output end of the isolation amplifier U2 is respectively connected to the input end of the window comparator U4 and the pin ADC1 of the MCU chip;

[0023] The output end of the isolation amplifier U3 is connected to the input end of the window comparator U5 and the pin ADC2 of the MCU chip respectively;

[0024] The output end of the window comparator U4 and the output end of the window comparator U5 are simultaneously connected to the input end of the U6 OR gate;

[0025] The output end of the U6 OR gate is connected to the pin INT of the MCU chip.

[0026] The beneficial effect of the present invention is to solve the problem of overvoltage or instability of digital power output caused by abnormal feedback loop of the power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the drawings required for use in the embodiments and the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is the principle diagram of the DC voltage detection feedback loop of the present invention;

[0029] Figure 2 It is a schematic diagram of the DC power supply detection of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0031] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can be applied to other similar scenarios based on these drawings without any creative work.

[0032] In addition, it can be understood that although the efforts made in this development process may be complex and lengthy, for ordinary technicians in the field related to the contents disclosed in the present invention, some design, manufacturing or production changes based on the technical contents disclosed in the present invention are just conventional technical means and should not be understood as the contents disclosed in the present invention are insufficient.

[0033] In order to better understand the solutions of the embodiments of the present application, some relevant terms and concepts that may be involved in the embodiments of the present application are first introduced below.

[0034] (1) Redundant circuit: Redundant circuit is a technology widely used in circuit design to improve the reliability and stability of the system. Redundant circuit forms a backup mechanism by adding additional components or paths outside the main circuit to ensure that when the main circuit fails, the system can still operate normally through another auxiliary circuit. Parallel redundancy is the most common form. It adds multiple identical components or subsystems to the same functional module. When the main component fails, the backup component immediately takes over its work.

[0035] (2) Isolated Operational Amplifier: An integrated circuit used for signal processing and amplification with the characteristics of high precision, high gain and low distortion. In motor drive systems, isolated operational amplifiers are widely used for voltage and current sampling because their linearity, bandwidth and drift performance are superior to other components such as Hall effect sensors.

[0036] (3) Window comparator: Also known as a dual-limit comparator, it is an electronic component used to detect whether the input signal is within two given voltage ranges. Its main feature is that when the input signal changes in one direction, such as monotonically increasing from a sufficiently low voltage to a sufficiently high voltage, the output voltage can jump twice. The window comparator is usually composed of two integrated operational amplifiers, which compare the input voltage through a reference voltage and a limiting circuit. When the input voltage exceeds the reference voltage, the output voltage will change, and when the input voltage is within the reference voltage range, the output voltage remains unchanged.

[0037] If not otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0038] See also Figure 1 , is a schematic diagram of a DC voltage detection feedback loop of the present invention;

[0039] The isolation operational amplifier U2 and the isolation operational amplifier U3 form a redundant circuit for DC voltage detection, which has the following specific structure; the input end of the isolation operational amplifier U2 and the input end of the isolation operational amplifier U3 are connected to the bus voltage measurement point V through the corresponding S1 signal line and S2 signal line respectively; the output end of the isolation operational amplifier U2 is connected to the input end of the window comparator U4 and the pin ADC1 of the MCU chip respectively; the output end of the isolation operational amplifier U3 is connected to the input end of the window comparator U5 and the pin ADC2 of the MCU chip respectively; the output end of the window comparator U4 and the output end of the window comparator U5 are simultaneously connected to the input end of the U6 OR gate; the output end of the U6 OR gate is connected to the pin INT of the MCU chip; the MCU chip stores software that can detect redundant circuits.

[0040] Specifically:

[0041] See also Figure 2, is a schematic diagram of the DC power supply detection of the present invention, which is a voltage detection isolation amplifier, that is, the general structure of the isolation amplifier U2 and the isolation amplifier U3, which includes: a number of resistors, an isolation amplifier, and an operational amplifier; the input end of the isolation amplifier is connected to the bus voltage measurement point V, that is, the bus input; the isolation amplifier outputs a differential voltage signal, and the isolation amplifier is connected to the in-phase input end and the reverse input end of the operational amplifier through two differential lines, and each of the two differential lines between the isolation amplifier and the operational amplifier is provided with at least one resistor; the operation method is also connected in parallel with at least one resistor; the output end of the operational amplifier is connected to the AD pin of the MCU chip; the isolation amplifier U2 and the isolation amplifier U3 form a redundant circuit for DC voltage detection, and the detection software carried by the MCU chip simultaneously The DC power supply detected by the isolation amplifier U2 and the isolation amplifier U3 in the redundant circuit makes the following judgment; when the S1 signal line corresponding to the isolation amplifier U2 is broken, it means that the output of the isolation amplifier U2 is 0V, and the detection software carried by the MCU chip cannot detect the bus voltage normally; the detection software carried by the MCU chip switches to the isolation amplifier U3 for detection, and the control loop PI outputs normally, and the MCU chip issues an S1 signal line break fault command; when the S2 signal line corresponding to the isolation amplifier U3 is broken, it means that the output of the isolation amplifier U3 is 0V, and the detection software carried by the MCU chip cannot detect the bus voltage normally; the detection software carried by the MCU chip switches to the isolation amplifier U2 for detection, and the control loop PI outputs normally, and the MCU chip issues an S2 signal line break fault command.

[0042] The thresholds set for window comparator U4 and window comparator U5 are both ±20% of the target voltage value. When a short line or overvoltage occurs in any window comparator, the output level of the window comparator is reversed, and the output signal is sent to the INT pin of the MCU chip through the U6 OR gate to achieve the purpose of outputting an interrupt signal to notify an external interrupt.

[0043] The bus voltage measurement point V is also connected to the diode D1, the DC / DC power module U7 and the EN pin of the MCU chip in sequence; the diode D1 and the DC / DC power module U7 constitute a power-on disconnection diagnostic circuit; the diode D1 is an anti-backflow device, and the bus voltage measurement point V is connected to the cathode of the diode D1; the D1 diode and the U7 power module constitute a power-on disconnection diagnostic circuit. In the initial stage of power-on of the entire power supply, the bus voltage measurement point V has not been established, and U2 and U3 cannot detect the DC voltage. Therefore, only when the bus voltage has an output can the output values ​​of U2 and U3 be used to determine whether the detection circuit is disconnected. Therefore, the disconnection diagnosis is introduced in this circuit. After the system is powered on, by controlling the enable pin of the U7 isolated power supply, U7 outputs 24V, which flows to the detection point V through the D1 diode. The detection circuits U2 and U3 output 23.3V (diode conduction voltage drop). The detection circuits S1 and S2 are normal. If S1 or S2 is disconnected, the corresponding U2 and U3 detections will have no output. The MCU chip (overall DSP) determines it as an alarm fault and turns off the output enable output of the U7 isolated power supply. The D1 diode is an anti-backflow circuit. When the voltage of the digital power supply is greater than 24V or higher (540V), the D1 diode can effectively prevent high voltage from flowing into the output of the U7 isolated power supply and damaging the U7 isolated power supply.

[0044] The above is a very detailed description of one or more embodiments of the present invention, but the content is only a specific example of the present invention and cannot be considered to limit the scope of application of the present invention. Any other methods and changes proposed based on the content of the present invention should fall within the scope of patent protection of the present invention.

Claims

1. A DC power supply feedback loop detection system, characterized in that: include: The isolation operational amplifier U2 and the isolation operational amplifier U3 form a redundant circuit for DC voltage detection; The input end of the isolation amplifier U2 and the input end of the isolation amplifier U3 are connected to the bus voltage measurement point V through corresponding S1 signal lines and S2 signal lines respectively.

2. A DC power supply feedback loop detection system according to claim 1, characterized in that: The isolation amplifier U2 and the isolation amplifier U3 are voltage detection isolation amplifiers with the same structure; The voltage detection isolation amplifier comprises: a plurality of resistors, an isolation amplifier, and an operational amplifier; The input end of the isolation amplifier is connected to the bus voltage measurement point V, i.e., the bus input; The isolation amplifier outputs a differential voltage signal, and the isolation amplifier is connected to the in-phase input terminal and the reverse input terminal of the operational amplifier through two differential lines, and at least one resistor is set on each of the two differential lines between the isolation amplifier and the operational amplifier; The calculation method device is also connected in parallel with at least one resistor; The output end of the operational amplifier is connected to the AD pin of the MCU chip.

3. A DC power supply feedback loop detection system according to claim 2, characterized in that: The isolation amplifier U2 and the isolation amplifier U3 form a redundant circuit for DC voltage detection, and the MCU chip simultaneously judges the DC power supply detected by the isolation amplifier U2 and the isolation amplifier U3 in the redundant circuit; When the S1 signal line corresponding to the isolation amplifier U2 is broken, it means that the output of the isolation amplifier U2 is 0V, and the bus voltage cannot be detected normally; at this time, the detection of the isolation amplifier U3 is switched, and the control loop PI outputs normally. At the same time, the MCU chip issues an S1 signal line break alarm fault instruction; When the S2 signal line corresponding to the isolation amplifier U3 is broken, it means that the output of the isolation amplifier U3 is 0V and the bus voltage cannot be detected normally. At this time, the detection of the isolation amplifier U2 is switched to the control loop PI, and the MCU chip issues an S2 signal line break alarm fault instruction.

4. A DC power supply feedback loop detection system according to claim 1, characterized in that: The thresholds set for the window comparator U4 and the window comparator U5 are both ±20% of the target voltage value. When a short line or overvoltage occurs in any window comparator, the output level of the window comparator is reversed, and the output signal is sent to the INT pin of the MCU chip through the U6 OR gate to achieve the purpose of outputting an interrupt signal to notify an external interrupt.

5. A DC power supply feedback loop detection system according to claim 1, characterized in that: The bus voltage measurement point V is also connected to the diode D1, the DC / DC power module U7 and the EN pin of the MCU chip in sequence; The diode D1 and the DC / DC power supply module U7 form a power-on disconnection diagnosis circuit; The diode D1 is a backflow prevention device, and the bus voltage measurement point V is connected to the cathode of the diode D1.

6. A DC power supply feedback loop detection system according to claim 5, characterized in that: The DC / DC power supply module U7 is specifically an isolated power supply, and provides a 24V voltage to flow to the bus voltage measurement point V through the diode D1.

7. A DC power supply feedback loop detection system according to claim 1, characterized in that: The output end of the isolation amplifier U2 is connected to the input end of the window comparator U4 and the pin ADC1 of the MCU chip respectively; The output end of the isolation amplifier U3 is connected to the input end of the window comparator U5 and the pin ADC2 of the MCU chip respectively; The output end of the window comparator U4 and the output end of the window comparator U5 are simultaneously connected to the input end of the U6 OR gate; The output end of the U6 OR gate is connected to the pin INT of the MCU chip.

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