Overcurrent protection circuit applied to inverter
By introducing an overcurrent signal detection module with switching transistors and filter capacitors into the inverter, the problems of slow response and insufficient accuracy of traditional inverter overcurrent protection circuits are solved, achieving fast and accurate overcurrent protection and improving the stability and reliability of the circuit.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAMEN COSTCO ELECTRONIC IND CO LTD
- Filing Date
- 2025-05-15
- Publication Date
- 2026-05-05
AI Technical Summary
Traditional inverter overcurrent protection circuits have slow response speed, insufficient protection accuracy, and are susceptible to high-frequency noise interference, resulting in unstable protection.
An overcurrent signal detection module, including first to fourth switching transistors and filter capacitors, is used to achieve fast and accurate overcurrent protection through current detection, signal amplification, and protection triggering mechanisms.
It improves the response speed and accuracy of inverter overcurrent protection, reduces high-frequency noise interference, and ensures safe and reliable circuit operation.
Smart Images
Figure CN224204758U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power supply protection, and in particular to an overcurrent protection circuit for inverters. Background Technology
[0002] In inverter applications, overcurrent protection is a crucial element in ensuring the safe operation of the equipment. Traditional inverter overcurrent protection circuits often employ fuses, circuit breakers, or simple electronic circuit breakers, which suffer from slow response times, insufficient protection accuracy, and inconvenient maintenance. For example, traditional protection circuits rely on the mechanical response of fuses when overcurrent is detected, leading to a delay in protection action. Furthermore, single-point protection designs cannot comprehensively monitor different load states, resulting in protection blind spots. In addition, high-frequency noise in the power supply can interfere with the current sampling signal, affecting the stability and reliability of the protection circuit. Therefore, there is a lack of overcurrent protection circuits in related technologies that can provide stable, reliable, and efficient overcurrent protection for inverters. Utility Model Content
[0003] This application provides an overcurrent protection circuit for inverters to solve the technical problems of slow response and insufficient protection accuracy in traditional protection circuits.
[0004] Therefore, in a first aspect, embodiments of this application provide an overcurrent protection circuit for an inverter, including an inverter module, a control module, and an overcurrent signal detection module. The control module is used to trigger the protection device to operate when it detects an overcurrent signal from the overcurrent signal detection module. The overcurrent signal detection module includes a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor. The collector and base of the first switching transistor are connected to the collector and emitter of the second switching transistor, respectively. The base of the first switching transistor and the emitter of the second switching transistor are connected to a first bias resistor, which is also connected to a first current detection point.
[0005] The collector and base terminals of the third switching transistor are connected to the collector and emitter terminals of the fourth switching transistor, respectively. The base terminal of the third switching transistor and the emitter terminal of the fourth transistor are connected together to a second bias resistor, which is also connected to a second current detection point.
[0006] In conjunction with the first aspect, in one embodiment of this application, the first switching transistor is further connected to a first filter capacitor, the second switching transistor is further connected to a second filter capacitor, the third switching transistor is connected to a third filter capacitor, and the fourth switching transistor is connected to a fourth filter capacitor.
[0007] According to an embodiment of this application, an overcurrent protection circuit for an inverter is provided. The circuit includes an inverter module, a control module, and an overcurrent signal detection module. The control module triggers a protection device to operate when it detects an overcurrent signal from the overcurrent signal detection module. The overcurrent signal detection module includes a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor. The collector and base of the first switching transistor are connected to the collector and emitter of the second switching transistor, respectively. The base of the first switching transistor and the emitter of the second switching transistor are connected together to a first bias resistor, which is also connected to a first current detection point. The collector and base of the third switching transistor are connected to the collector and emitter of the fourth switching transistor, respectively. The base of the third switching transistor and the emitter of the fourth switching transistor are connected together to a second bias resistor, which is also connected to a second current detection point. In this scheme, the current change is monitored in real time through the current monitoring point. Once an overcurrent signal is detected, the signal is amplified by the above-mentioned transistor and triggers the protection mechanism to ensure the safe operation of the circuit. It has the advantages of fast response and high accuracy. Attached Figure Description
[0008] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort. In addition, in the drawings, the same parts use the same reference numerals, and the drawings are not drawn to scale.
[0009] Figure 1 A schematic diagram of an overcurrent signal detection module for an overcurrent protection circuit in an inverter, provided in an embodiment of this application;
[0010] Figure 2 This is a schematic diagram of an inverter module with an overcurrent protection circuit applied to an inverter, provided as an embodiment of this application. Detailed Implementation
[0011] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0012] See Figure 1As shown in the figure, this application embodiment provides an overcurrent protection circuit for an inverter, including an inverter module, a control module, and an overcurrent signal detection module. The control module is used to trigger the protection device to quickly cut off the current or take other measures when the signal from the overcurrent signal detection module indicates an overcurrent, so as to prevent the circuit from being damaged due to overcurrent. The overcurrent signal detection module includes: a first switching transistor Q1, a second switching transistor Q2, a third switching transistor Q3, and a fourth switching transistor Q4. The collector and base terminals of the first switching transistor Q1 are connected to the collector and emitter terminals of the second switching transistor Q2, respectively. The base terminal of the first switching transistor Q1 and the emitter terminal of the second switching transistor Q2 are connected to a first bias resistor R2. The first bias resistor R2 is also connected to a first current detection point I-SENSE1.
[0013] The collector and base terminals of the third switching transistor Q3 are connected to the collector and emitter terminals of the fourth switching transistor Q4, respectively. The base terminal of the third switching transistor Q3 and the emitter terminal of the fourth switching transistor Q4 are connected to the second bias resistor R3, which is also connected to the current detection point I-SENSE2.
[0014] In one embodiment of this application, specific reference is made. Figure 1 As shown, to improve the accuracy and reliability of the circuit, the first switching transistor Q1 is connected to a first filter capacitor C1, the second switching transistor Q2 is connected to a second filter capacitor C2, the third switching transistor Q3 is connected to a third filter capacitor C3, and the fourth switching transistor Q4 is connected to a fourth filter capacitor C4. The filter capacitors C1 to C4 in the circuit serve to filter and stabilize the signal. They ensure the accuracy and reliability of the current detection signal and prevent false triggering or missed triggering caused by signal interference or noise.
[0015] The overcurrent protection circuit for inverters provided in this application embodiment achieves overcurrent protection through three steps: current detection, signal amplification, and protection triggering. The current detection point monitors current changes in real time. Once an overcurrent is detected, the signal is amplified by a transistor to trigger the protection mechanism, ensuring the safe operation of the circuit. The capacitor in the circuit acts as a filter and stabilizer for the signal, improving the reliability and accuracy of the protection.
[0016] Specific reference Figure 2 As shown, in the specific implementation of this scheme, regarding current detection, I-SENSE1 and I-SENSE2 in the inverter module circuit are current detection points, and the current change in the circuit is monitored in real time through sampling resistor RS1 and sampling resistor RS2.
[0017] When the current exceeds the set threshold, these detection points will sense an overcurrent signal.
[0018] Regarding signal amplification, in the overcurrent signal detection module, when the current is in the positive half-cycle, the overcurrent signal is transmitted to the bases of transistors Q1 and Q3 through the first bias resistor R2 and the second bias resistor R3. The base-emitter voltage difference VBE reaches the turn-on voltage, and the first switching transistor Q1 and the third switching transistor Q3 conduct, amplifying the weak current signal. When the current is in the negative half-cycle, the bases of the second switching transistor Q2 and the fourth switching transistor Q4 are connected to the reference ground and are at zero potential. The overcurrent signal is transmitted to the emitters of the second switching transistor Q2 and the fourth switching transistor Q4 through the first bias resistor R2 and the second bias resistor R3. The base-emitter voltage difference VBE reaches the turn-on voltage, and the third switching transistor Q3 and the fourth switching transistor Q4 conduct, amplifying the weak current signal.
[0019] Protection Trigger: The amplified signal is connected to the FLT-1 signal line through the collectors of the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q1. FLT-1 is connected to +VCC and initially has a high potential. When an overcurrent signal is detected, the FLT-1 signal is pulled low. The control module receives the change in the FLT-1 level, and the protection device will quickly cut off the current or take other measures to prevent the circuit from being damaged due to overcurrent.
[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0021] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. An overcurrent protection circuit for an inverter, characterized in that, The system includes an inverter module, a control module, and an overcurrent signal detection module. The control module triggers a protection device when it detects an overcurrent signal from the overcurrent signal detection module. The overcurrent signal detection module includes a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor. The collector and base of the first switching transistor are connected to the collector and emitter of the second switching transistor, respectively. The base of the first switching transistor and the emitter of the second switching transistor are connected together to a first bias resistor, which is also connected to a first current detection point. The collector and base of the third switching transistor are connected to the collector and emitter of the fourth switching transistor, respectively. The base of the third switching transistor and the emitter of the fourth switching transistor are connected together to a second bias resistor, which is also connected to a second current detection point.
2. The circuit according to claim 1, characterized in that, The first switching transistor is also connected to a first filter capacitor, the second switching transistor is also connected to a second filter capacitor, the third switching transistor is connected to a third filter capacitor, and the fourth switching transistor is connected to a fourth filter capacitor.