Inverter AC output protection circuit
By designing an AC output protection circuit in the inverter, and using current transformers and comparators to detect and compare currents, the problem of the inverter lacking protection measures in harsh environments is solved, and safety is improved to prevent leakage and false electric shock.
Patent Information
- Application Number
- CN202420321396.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-21
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-02-21
AI Technical Summary
The inverter lacks protective measures in harsh application environments, which poses safety risks.
An inverter AC output protection circuit is designed to detect the output current of the AC input power supply through a current transformer, and a comparator is used to compare and detect the current. When the current is unbalanced, a control command is output to the inverter to turn off the output.
It improves the safety of the inverter circuit, prevents leakage and accidental electric shock, and reduces safety hazards during use.
Smart Images
Figure CN222654815U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of inverters, in particular to an inverter AC output protection circuit. Background Art
[0002] The inverter generally includes a DC filter circuit, a DC / DC boost circuit, a DC / AC inverter circuit and an AC filter circuit, a boost microcontroller for generating PWM waves to control the DC / DC boost circuit, and an inverter microcontroller for generating PWM waves to control the DC / AC inverter circuit. After the DC input, it first passes through the DC filter circuit to reduce ripple current and suppress electromagnetic interference, and then the DC / DC boost circuit converts the low-voltage DC into high-voltage DC, and then the DC / AC inverter circuit converts the high-voltage DC into a square wave of SPWM sinusoidal pulse width modulation, and finally outputs the AC voltage through the AC filter circuit.
[0003] The inverter can output various waveforms such as modified wave and sine wave according to the needs. It is usually used in automobile on-board equipment, field power engineering, solar home independent power generation system, etc. The use environment is relatively harsh. For example, there are metal conductive parts everywhere in the car, and the metal conductor parts of the car are connected to the negative pole of the battery. The inverter usually has a high internal voltage. When the equipment leaks or people are accidentally electrocuted, there are certain safety hazards when using it because the inverter itself has no leakage protection device. Summary of the invention
[0004] In the prior art, some inverters are used in harsh environments but lack protective measures, which poses certain safety risks.
[0005] In view of the above problems, an inverter AC output protection circuit is proposed. The current at the output end of the inverter's AC input power supply is detected by using a current transformer, and the detected current is compared by a comparator. When the current is unbalanced, the comparator unit inputs a control instruction to the inverter, thereby prompting the inverter to shut down the output, thereby improving the safety of the inverter circuit.
[0006] An inverter AC output protection circuit, comprising:
[0007] AC power supply;
[0008] Inverter;
[0009] Current protection device;
[0010] The AC power source is electrically connected to the inverter;
[0011] The inverter is used to process the input AC power supply voltage to obtain the required voltage waveform and output it to the load;
[0012] The current protection device is electrically connected to the output end of the AC power supply and the inverter, and is used to detect whether the output current of the output end of the AC power supply is balanced, and output a control instruction to the inverter to shut down the output when it is unbalanced.
[0013] In combination with the inverter AC output protection circuit described in the utility model, in a first possible implementation manner, the current protection device includes:
[0014] A first detection unit;
[0015] A second detection unit;
[0016] Comparator unit;
[0017] The first detection unit and the second detection unit are electrically connected to the first end and the second end of the comparator unit respectively;
[0018] The first detection unit is also electrically connected to the first output end of the AC power supply, and is used to detect the current of the first output end of the AC power supply to obtain a first detection current. The second detection unit is also electrically connected to the second output end of the AC power supply, and is used to detect the current of the second output end of the AC power supply to obtain a second detection current, and outputs the second detection current to the comparator unit respectively.
[0019] The comparator unit is used for comparing the first detection current with the second detection current.
[0020] In combination with the first possible implementation manner of the utility model, in a second possible implementation manner, the current protection device further includes:
[0021] Output unit;
[0022] The output unit is electrically connected to the comparator unit and the inverter respectively, and is used to output the comparison result to the inverter.
[0023] In combination with the second possible implementation manner of the utility model, in a third possible implementation manner, the inverter includes:
[0024] Action unit;
[0025] The action unit is used to turn off the output after receiving the control command signal of current imbalance.
[0026] In combination with the third possible implementation manner of the utility model, in a fourth possible implementation manner, the first detection unit includes:
[0027] a first current transformer;
[0028] A first diode;
[0029] a first resistor;
[0030] A second resistor;
[0031] The first end of the first current transformer is electrically connected to the first output end of the AC power supply, the second end is electrically connected to the first end of the inverter, the third end is electrically connected to the first end of the first resistor, and the fourth end is electrically connected to the anode of the first diode. The cathode of the first diode is electrically connected to the first end of the second resistor. The second end of the first resistor and the second end of the second resistor are connected together and electrically connected to the first end of the comparator unit.
[0032] In combination with the fourth possible implementation manner of the utility model, in a fifth possible implementation manner, the second detection unit includes:
[0033] a second current transformer;
[0034] A second diode;
[0035] The third resistor;
[0036] a fourth resistor;
[0037] The first end of the second current transformer is electrically connected to the second output end, the second end is electrically connected to the second end of the inverter, the third end is electrically connected to the first end of the third resistor, the fourth end is electrically connected to the anode of the second diode, the cathode of the second diode is electrically connected to the first end of the fourth resistor, the second end of the third resistor and the second end of the fourth resistor are connected together and electrically connected to the second end of the comparator unit;
[0038] The third end of the first current transformer, the first end of the first resistor, the third end of the second current transformer, and the first end of the third resistor are connected in common and then grounded.
[0039] In combination with the fifth possible implementation manner of the utility model, in a sixth possible implementation manner, the comparator unit includes:
[0040] a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a comparator;
[0041] The first end of the fifth resistor is commonly connected with the second end of the first resistor and the second end of the second resistor, the second end of the fifth resistor is electrically connected with the first end of the seventh resistor and the first input end of the comparator, and the second end of the seventh resistor is grounded;
[0042] The first end of the sixth resistor is connected to the second end of the third resistor and the second end of the fourth resistor, the second end of the sixth resistor is electrically connected to the first end of the eighth resistor and the second input end of the comparator, the second end of the eighth resistor is electrically connected to the output end of the comparator and the first end of the ninth resistor, and the second end of the ninth resistor is output.
[0043] In combination with the fifth possible implementation manner of the utility model, in a sixth possible implementation manner, the inverter further includes:
[0044] A first inverter output terminal and a second inverter output terminal;
[0045] The first inverter output terminal and the second inverter output terminal are electrically connected to a first terminal and a second terminal of a load respectively.
[0046] The inverter AC output protection circuit described in the utility model is implemented by using current transformers to detect the current at the output end of the inverter's AC input power supply, and comparing the detected currents through a comparator. When the current is unbalanced, the comparator unit inputs a control instruction to the inverter, thereby prompting the inverter to shut down the output, thereby improving the safety of the inverter circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0048] Figure 1 This is a connection diagram of the AC output protection circuit module of the inverter of the utility model;
[0049] Figure 2 This is a schematic diagram of the connection of the protection device module of the utility model;
[0050] Figure 3 The utility model is a schematic diagram of the structure of the inverter AC output protection circuit. DETAILED DESCRIPTION
[0051] The following will be combined with the drawings in the utility model to clearly and completely describe the technical solution in the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the utility model.
[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0053] In the prior art, some inverters are used in harsh environments but lack protective measures, which poses certain safety risks.
[0054] In view of the above problems, an AC output protection circuit of the inverter 300 is proposed.
[0055] like Figure 1 , Figure 1 The utility model is a schematic diagram of the connection module of the AC output protection circuit of the inverter 300; an AC output protection circuit of the inverter 300 includes an AC power supply 100, an inverter 300, and a current protection device 200; the AC power supply 100 is electrically connected to the inverter 300; the inverter 300 is used to process the input voltage of the AC power supply 100 to obtain the required voltage waveform and output it to the load; the current protection device 200 is electrically connected to the output end of the AC power supply 100, and is used to detect whether the output current of the output end of the AC power supply 100 is balanced, and output a control instruction to the inverter 300 when it is unbalanced to turn off the output. By using the current transformer T to detect the current of the output end of the AC input power supply of the inverter 300 respectively, and comparing the detected current through the comparator, when the current is unbalanced, the comparator unit 230 inputs a control instruction to the inverter 300, thereby prompting the inverter 300 to turn off the output, thereby improving the safety of the inverter 300 circuit.
[0056] Furthermore, if Figure 2 , Figure 2 It is a schematic diagram of the module connection of the current protection device 200 of the utility model; the current protection device 200 includes a first detection unit 210, a second detection unit 220, and a comparator unit 230; the first detection unit 210 and the second detection unit 220 are electrically connected to the first end and the second end of the comparator unit 230 respectively; the first detection unit 210 is used to detect the first output end of the AC power supply 100 to obtain a first detection current, and the second detection unit 220 is used to detect the second output end of the AC power supply 100 to obtain a second detection current, and output them to the comparator unit 230 respectively; the comparator unit 230 is used to compare the first detection current with the second detection current.
[0057] If the first detection current collected by the first current transformer T1 on the L phase is equal to the second detection current of the second current transformer T2 on the N phase, the output end of the comparator U1 outputs 0V, and there is no leakage at the output. If the collected first detection current and the second detection current are not equal, the output end of the comparator U1 is not equal to 0V, and the inflow current is not equal to the output current. It can be judged that there is a leakage, and the inverter will automatically shut down the output to achieve the protection purpose.
[0058] Furthermore, the current protection device 200 further includes: an output unit 240 ; the output unit 240 is electrically connected to the comparator unit 230 and the inverter 300 , respectively, and is used to output the comparison result to the inverter 300 .
[0059] Furthermore, the inverter 300 includes an action unit, which is used to shut down the output after receiving a control command signal of current imbalance. The action unit can be a device such as a relay or a contactor. After receiving a signal of current imbalance, the relay or contactor is actuated to shut down the output of the inverter 300.
[0060] like Figure 3 , Figure 3 It is a schematic diagram of the structure of the AC output protection circuit of the inverter 300 of the utility model. The first detection unit 210 includes a first current transformer T1, a first diode D1, a first resistor R1, and a second resistor R2; the first end of the first current transformer T1 is electrically connected to the first output end (L phase) of the AC power supply, the second end is electrically connected to the first end of the inverter 300, the third end is electrically connected to the first end of the first resistor R1, and the fourth end is electrically connected to the anode of the first diode D1, the cathode of the first diode D1 is electrically connected to the first end of the second resistor R2, and the second end of the first resistor R1 and the second end of the second resistor R2 are connected together and electrically connected to the first end of the comparator unit 230.
[0061] Further, the second detection unit 220 includes a second current transformer T2, a second diode D2, a third resistor R3, and a fourth resistor R4; the first end of the second current transformer T2 is electrically connected to the second output end (N phase) of the AC power supply, the second end is electrically connected to the second end of the inverter 300, the third end is electrically connected to the first end of the third resistor R3, and the fourth end is electrically connected to the anode of the second diode D2, the cathode of the second diode D2 is electrically connected to the first end of the fourth resistor R4, the second end of the third resistor R3 and the second end of the fourth resistor R4 are connected together and then electrically connected to the second end of the comparator unit 230; the third end of the first current transformer T1, the first end of the first resistor R1, the third end of the second current transformer T2, and the first end of the third resistor R3 are connected together and then grounded.
[0062] Further, the comparator unit 230 includes: a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a comparator U1;
[0063] A first end of the fifth resistor R5 is connected to the second end of the first resistor R1 and the second end of the second resistor R2, a second end of the fifth resistor R5 is electrically connected to a first end of the seventh resistor R7 and the first input end of the comparator U1, and a second end of the seventh resistor R7 is grounded;
[0064] The first end of the sixth resistor R6 is connected to the second end of the third resistor R3 and the second end of the fourth resistor R4. The second end of the sixth resistor R6 is electrically connected to the first end of the eighth resistor R8 and the second input end of the comparator U1. The second end of the eighth resistor R8 is electrically connected to the output end of the comparator and the first end of the ninth resistor R9. The second end of the ninth resistor R9 is output.
[0065] Furthermore, the inverter 300 further includes a first inverter output terminal and a second inverter output terminal; the first inverter output terminal and the second inverter output terminal are electrically connected to a first terminal and a second terminal of the load 400 respectively.
[0066] The inverter AC output protection circuit of the utility model is implemented by using current transformers to detect the current at the output end of the inverter's AC input power supply, and comparing the detected current through a comparator. When the current is unbalanced, the comparator unit 230 inputs a control instruction to the inverter, thereby prompting the inverter to shut down the output, thereby improving the safety of the inverter circuit.
[0067] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. An inverter AC output protection circuit, characterized in that: include: AC power supply; Inverter; Current protection device; The AC power source is electrically connected to the inverter; The inverter is used to process the input AC power supply voltage to obtain the required voltage waveform and output it to the load; The current protection device is electrically connected to the output end of the AC power supply and the inverter, and is used to detect whether the output current of the output end of the AC power supply is balanced, and output a control instruction to the inverter to shut down the output when it is unbalanced.
2. The inverter AC output protection circuit according to claim 1, characterized in that: The current protection device comprises: A first detection unit; A second detection unit; Comparator unit; The first detection unit and the second detection unit are electrically connected to the first end and the second end of the comparator unit respectively; The first detection unit is also electrically connected to the first output end of the AC power supply, and is used to detect the current of the first output end of the AC power supply to obtain a first detection current. The second detection unit is also electrically connected to the second output end of the AC power supply, and is used to detect the current of the second output end of the AC power supply to obtain a second detection current, and outputs the second detection current to the comparator unit respectively. The comparator unit is used for comparing the first detection current with the second detection current.
3. The inverter AC output protection circuit according to claim 2, characterized in that: The current protection device also includes: Output unit; The output unit is electrically connected to the comparator unit and the inverter respectively, and is used to output the comparison result to the inverter.
4. The inverter AC output protection circuit according to claim 3, characterized in that: The inverter comprises: Action unit; The action unit is used to turn off the output after receiving the control command signal of current imbalance.
5. The inverter AC output protection circuit according to claim 4, characterized in that: The first detection unit comprises: a first current transformer; A first diode; a first resistor; A second resistor; The first end of the first current transformer is electrically connected to the first output end of the AC power supply, the second end is electrically connected to the first end of the inverter, the third end is electrically connected to the first end of the first resistor, and the fourth end is electrically connected to the anode of the first diode. The cathode of the first diode is electrically connected to the first end of the second resistor. The second end of the first resistor and the second end of the second resistor are connected together and electrically connected to the first end of the comparator unit.
6. The inverter AC output protection circuit according to claim 5, characterized in that: The second detection unit comprises: a second current transformer; A second diode; The third resistor; a fourth resistor; The first end of the second current transformer is electrically connected to the second output end of the AC power supply, the second end is electrically connected to the second end of the inverter, the third end is electrically connected to the first end of the third resistor, the fourth end is electrically connected to the anode of the second diode, the cathode of the second diode is electrically connected to the first end of the fourth resistor, the second end of the third resistor and the second end of the fourth resistor are connected together and electrically connected to the second end of the comparator unit; The third end of the first current transformer, the first end of the first resistor, the third end of the second current transformer, and the first end of the third resistor are connected in common and then grounded.
7. The inverter AC output protection circuit according to claim 6, characterized in that: The comparator unit comprises: a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a comparator; The first end of the fifth resistor is commonly connected with the second end of the first resistor and the second end of the second resistor, the second end of the fifth resistor is electrically connected with the first end of the seventh resistor and the first input end of the comparator, and the second end of the seventh resistor is grounded; The first end of the sixth resistor is connected to the second end of the third resistor and the second end of the fourth resistor, the second end of the sixth resistor is electrically connected to the first end of the eighth resistor and the second input end of the comparator, the second end of the eighth resistor is electrically connected to the output end of the comparator and the first end of the ninth resistor, and the second end of the ninth resistor is output.
8. The inverter AC output protection circuit according to claim 7, characterized in that: The inverter further comprises: A first inverter output terminal and a second inverter output terminal; The first inverter output terminal and the second inverter output terminal are electrically connected to a first terminal and a second terminal of a load respectively.