Inverter switch control circuit, inverter switch control method, and inverter power supply

Abstract

The application belongs to the technical field of inverter control, and provides an inverter switch control circuit, an inverter switch control method and an inverter power supply. The primary side current sampling signal of a transformer is compared with a preset overcurrent threshold signal through an overcurrent detection circuit, and an overcurrent detection signal is output according to the comparison result. Then, the parameters of the overcurrent detection signal are monitored by a main control circuit to generate overcurrent monitoring data, and a lock mode control signal is generated according to the overcurrent monitoring data. The mode control circuit generates a self-lock control signal according to the lock mode control signal to control the lock mode of the overcurrent detection signal to switch between the wave-by-wave disable mode and the permanent disable mode. The overcurrent self-lock circuit outputs a switch control signal according to the lock mode and the overcurrent detection signal to control the conduction and shutdown of the inverter switch, so that the power switch tube can switch the working state according to the application scene, and the continuous operation and safe operation of the power switch tube are ensured.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of inverter control, and particularly relates to an inverter switch control circuit, an inverter switch control method and an inverter power supply. BACKGROUND

[0002] At present, although the wave-by-wave disabling of the power switch tube can maintain the normal (uninterrupted or less interrupted) operation of the inverter, it cannot guarantee the highest safety operation level of the inverter switch; although the permanent disabling of the power switch tube can guarantee the highest safety operation level of the inverter switch, it is difficult to maintain the normal (continuous) operation of the inverter.

[0003] However, the wave-by-wave disabling and the permanent disabling of the power switch tube are mutually exclusive in principle, and their respective advantages cannot be compatible and complementary. If the working state of the power switch tube is not switched in time in different application scenarios, it is easy to cause output errors and cause serious losses. SUMMARY

[0004] The embodiments of the present application provide an inverter switch control circuit, an inverter switch control method and an inverter power supply, and aim to solve the problem that the power switch tube cannot switch the working state according to the application scenario to simultaneously guarantee the continuous operation and the safety operation.

[0005] The first aspect of the embodiments of the present application provides an inverter switch control circuit connected with the inverter switch, comprising:

[0006] An overcurrent detection circuit configured to compare a primary side current sampling signal of a transformer with a preset overcurrent threshold signal, and output an overcurrent detection signal according to a comparison result;

[0007] A main control circuit configured to monitor parameters of the overcurrent detection signal to generate overcurrent monitoring data, and generate a lock mode control signal according to the overcurrent monitoring data;

[0008] A mode control circuit connected with the main control circuit, configured to generate a self-lock control signal according to the lock mode control signal;

[0009] An overcurrent self-lock circuit connected with the overcurrent detection circuit, the mode control circuit and the inverter switch, configured to switch a lock mode of the overcurrent detection signal according to the self-lock control signal, and output a switch control signal according to the lock mode and the overcurrent detection signal to control conduction and turn-off of the inverter switch; wherein the lock mode includes a wave-by-wave disabling mode and a permanent disabling mode.

[0010] In one embodiment, the inverter switch control circuit further comprises:

[0011] A current detection circuit is configured to sample a current of a primary winding of the transformer to generate the primary current sampling signal.

[0012] In one embodiment, the overcurrent self-locking circuit is further configured to switch a locking mode of the overcurrent detection signal to the step-by-step disabling mode when the self-locking control signal is at the first level, and output a corresponding switch control signal to control the inverter switch to be turned on or turned off according to the overcurrent detection signal.

[0013] The overcurrent self-locking circuit is further configured to switch the locking mode of the overcurrent detection signal to the permanent disabling mode when the self-locking control signal is at the second level, and output a corresponding switch control signal to control the inverter switch to be turned off.

[0014] In one embodiment, the master control circuit comprises:

[0015] A signal monitoring module is configured to receive the overcurrent detection signal and monitor a parameter of the overcurrent detection signal to generate overcurrent monitoring data.

[0016] A data calculation module is configured to receive the overcurrent monitoring data and generate a locking mode control signal according to the overcurrent monitoring data.

[0017] In one embodiment, the signal monitoring module is further configured to monitor a level of the overcurrent detection signal, determine that a current of the primary winding of the transformer is in an overcurrent state when the overcurrent detection signal is at a low level, and generate corresponding overcurrent monitoring data to send to the data calculation module.

[0018] In one embodiment, the signal monitoring module is further configured to monitor an overcurrent frequency and an overcurrent time of the overcurrent detection signal, and generate corresponding overcurrent monitoring data to send to the data calculation module.

[0019] The data calculation module is further configured to generate a corresponding mode control signal to switch the locking mode of the overcurrent detection signal to a permanent disabling mode when the overcurrent frequency reaches a preset frequency within a preset time period.

[0020] In one embodiment, the overcurrent self-locking circuit comprises a first NAND gate, a second NAND gate, and a third NAND gate.

[0021] A first input pin of the first NAND gate is connected to the overcurrent detection circuit.

[0022] An output pin of the first NAND gate, a first input pin of the second NAND gate, a first input pin of the third NAND gate, and a second input pin of the third NAND gate are connected in common.

[0023] The second input pin of the second NAND gate is connected with the mode control circuit, and the output pin of the second NAND gate is connected with the second input pin of the first NAND gate.

[0024] The output pin of the third NAND gate is used for outputting the switch control signal.

[0025] In one embodiment, the mode control circuit comprises a switching switch tube and a current-limiting resistor.

[0026] The first end of the current-limiting resistor is connected with a power supply, the second end of the current-limiting resistor and the first end of the switching switch tube are commonly connected with the overcurrent self-locking circuit, the second end of the switching switch tube is connected with the ground, and the control end of the switching switch tube is connected with the master control circuit.

[0027] The second aspect of the embodiment of the application further provides an inverter switch control method, comprising:

[0028] The primary side current sampling signal of the transformer is compared with a preset overcurrent threshold signal, and an overcurrent detection signal is output according to the comparison result;

[0029] The parameters of the overcurrent detection signal are monitored to generate overcurrent monitoring data, and a lock mode control signal is generated according to the overcurrent monitoring data;

[0030] The self-locking control signal is generated according to the lock mode control signal;

[0031] The lock mode of the overcurrent detection signal is switched according to the self-locking control signal, and a switch control signal is output according to the lock mode and the overcurrent detection signal, so as to control the conduction and turn-off of the inverter switch; wherein the lock mode comprises a wave-by-wave disable mode and a permanent disable mode.

[0032] The third aspect of the embodiment of the application further provides an inverter power supply, comprising: an inverter switch and an inverter switch control circuit as described in any one of the above; or

[0033] The inverter power supply comprises an inverter switch and a switch driving circuit, and the switch driving circuit is used for executing the inverter switch control method as described above.

[0034] Compared with the prior art, the embodiment of the present application has the beneficial effects that: the primary side current sampling signal of the transformer is compared with the preset overcurrent threshold signal through the overcurrent detection circuit, and an overcurrent detection signal is output according to the comparison result; then the parameters of the overcurrent detection signal are monitored by the main control circuit to generate overcurrent monitoring data, and a lock mode control signal is generated according to the overcurrent monitoring data, the mode control circuit generates a self-locking control signal according to the lock mode control signal to control the lock mode of the overcurrent detection signal to switch between the wave-by-wave disabling mode and the permanent disabling mode, and the overcurrent self-locking circuit outputs a switch control signal according to the lock mode and the overcurrent detection signal to control the conduction and shutdown of the inverter switch, so that the power switch tube can switch the working state according to the application scene, and the continuous operation and safe operation of the power switch tube are ensured. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0036] Figure 1 is a schematic diagram of an inverter switch control circuit provided by the embodiment of the present application Figure 1 ;

[0037] Figure 2 is a schematic diagram of an inverter switch control circuit provided by the embodiment of the present application Figure 2 ;

[0038] Figure 3 is a schematic diagram of an inverter switch control circuit provided by the embodiment of the present application Figure 3 ;

[0039] Figure 4 is a schematic diagram of an inverter switch control circuit provided by the embodiment of the present application Figure 4 ;

[0040] Figure 5 is a waveform schematic diagram of an inverter switch control circuit provided by the embodiment of the present application

[0041] Figure 6 is a flowchart of an inverter switch control method provided by the embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present application and not to limit the present application.

[0043] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0044] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0045] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0046] The disablement of the inverter switch (i.e. inverter power switch tube) is divided into wave-by-wave disablement and permanent disablement.

[0047] Wave-by-wave disablement is that when overcurrent occurs during the duty cycle effective period of the current pulse width modulation (PWM) cycle, the power switch tube is turned off, and the power switch tube can be turned on again when the duty cycle of the next PWM cycle comes. Therefore, wave-by-wave disablement can ensure the (instantaneous) safety of the power switch tube and maintain the normal operation of the inverter, but cannot guarantee the permanent safety of the inverter power switch tube.

[0048] Permanent disablement is that when overcurrent occurs during the duty cycle effective period of the current PWM cycle, the power switch tube is turned off, and the power switch tube cannot be enabled and turned on again permanently in the current inverter power-on state, unless the inverter is powered off and powered on again. Therefore, permanent disablement can guarantee the absolute safety of the power switch tube and the inverter, which completely avoids the overcurrent and / or overheat damage caused by the power switch tube being turned on again before the cause of the inverter transformer primary side overcurrent is cleared, but cannot maintain the normal operation of the inverter.

[0049] However, the wave-by-wave disabling can maintain the normal (uninterrupted or less interrupted) operation of the inverter, but cannot guarantee the highest safety operation level of the inverter power switch tube;

[0050] The permanent disabling can guarantee the highest safety operation level of the inverter power switch tube, but it is difficult to maintain the normal (continuous) operation of the inverter. The existing two power switch tube disabling strategies are mutually exclusive in principle, and their respective advantages cannot be compatible and complementary.

[0051] To solve the above technical problems, an inverter switch control circuit is provided in an embodiment of the present application, which is connected with an inverter switch and used for controlling the turn-on and turn-off of the inverter switch.

[0052] In the embodiment, the inverter switch control circuit is combined with the inverter switch and the transformer. Figure 1 As shown in the figure, the inverter switch control circuit at least includes an overcurrent detection circuit 100, a master control circuit 200, a mode control circuit 300 and an overcurrent self-locking circuit 400.

[0053] Specifically, the overcurrent detection circuit 100 is used for comparing the primary side current sampling signal of the transformer with the preset overcurrent threshold signal and outputting an overcurrent detection signal according to the comparison result; the master control circuit 200 is used for monitoring the parameters of the overcurrent detection signal to generate overcurrent monitoring data and generating a lock mode control signal according to the overcurrent monitoring data; the mode control circuit 300 is connected with the master control circuit 200 and used for generating a self-locking control signal according to the lock mode control signal; the overcurrent self-locking circuit 400 is connected with the overcurrent detection circuit 100, the mode control circuit 300 and the inverter switch 600 and used for switching the lock mode of the overcurrent detection signal according to the self-locking control signal and outputting a switch control signal according to the lock mode and the overcurrent detection signal to control the turn-on and turn-off of the inverter switch 600.

[0054] In the embodiment, the inverter switch 600 is connected in series with the primary winding of the transformer and turns on or turns off according to the received switch control signal. When the transformer secondary side current of the inverter increases, the primary side current will increase due to the return effect of electromagnetic coupling. For example, when the impedance of the transformer secondary side is too small, the secondary side current will be too large, which causes the current of the power switch tube connected in series with the primary side of the transformer to be too large. If this current stress exceeds the maximum current stress limit of the power switch tube, it will cause thermal failure damage of the power switch tube. When the transformer magnetic core is saturated by magnetic flux or the temperature rises too high, similar phenomena and the same consequences as when the impedance of the transformer secondary side is too small will occur.

[0055] In the embodiment, the overcurrent detection circuit 100 compares the detected inverter transformer primary side current (i.e., the primary side current sampling signal) with the set overcurrent threshold (i.e., the preset overcurrent threshold signal), and generates a corresponding overcurrent detection signal according to the comparison result. The overcurrent detection signal is outputted after the overcurrent self-locking circuit 400, and a corresponding switch control signal is outputted to control the conduction and shutdown of the inverter switch 600. In the overcurrent self-locking circuit 400, the locking mode of the overcurrent detection signal includes the wave-by-wave disabling mode and the permanent disabling mode. The main control circuit 200 obtains overcurrent monitoring data by monitoring the parameters of the overcurrent detection signal, and generates a corresponding locking mode control signal by processing the overcurrent monitoring data based on the preset mode switching condition. Then, the mode control circuit 300 converts the locking mode control signal into a corresponding self-locking control signal, so as to switch the locking mode of the overcurrent detection signal in the overcurrent self-locking circuit 400, and then the overcurrent self-locking circuit 400 generates a corresponding switch control signal by processing the overcurrent detection signal based on the locking mode, so as to realize the timely, effective and reliable shutdown (disabling) or conduction of the power switch tube, and ensure the stable and safe operation of the inverter.

[0056] Further, the main control circuit 200 monitors the parameters of the overcurrent detection signal, and makes a quick, accurate and intelligent judgment and processing on the necessity of the continued existence of the overcurrent detection signal (i.e., the disabling signal) for controlling the shutdown of the inverter switch 600, generates a locking mode control signal to control the mode control circuit 300 to set a corresponding locking mode, and ensures the continuous operation of the inverter.

[0057] Specifically, the main control circuit 200 analyzes and processes the overcurrent monitoring data. When the parameters of the overcurrent detection signal meet the wave-by-wave disabling mode, the main control circuit 200 outputs a wave-by-wave disabling signal as a corresponding locking mode control signal to control the locking mode of the overcurrent detection signal in the overcurrent self-locking circuit 400 to be switched to the wave-by-wave disabling mode. When the parameters of the overcurrent detection signal meet the permanent disabling mode, the main control circuit 200 outputs a permanent disabling signal as a corresponding locking mode control signal to control the locking mode of the overcurrent detection signal in the overcurrent self-locking circuit 400 to be switched to the permanent disabling mode.

[0058] When the condition causing the wave-by-wave disabling signal still exists, the wave-by-wave disabling signal can be upgraded to a permanent disabling signal, the overcurrent detection signal is in a permanent disabling mode, the inverter switch 600 is turned off, and the inverter stops running; otherwise, the wave-by-wave disabling signal will be removed, and the inverter maintains running. When the condition causing the permanent disabling signal no longer exists, the permanent disabling signal can be removed, and the inverter can be allowed to run again without going through the cumbersome process of power-off and re-powering; otherwise, the inverter still stops running. In this way, both the continuous running and the safe running of the inverter are effectively and efficiently better guaranteed.

[0059] In an application embodiment, if the voltage of the primary side current sampling signal of the transformer is greater than the voltage of the preset overcurrent threshold signal, a corresponding first overcurrent detection signal is generated, at this time the first overcurrent detection signal as a disabling signal can be used to control the inverter switch 600 to turn off, and if the voltage of the primary side current sampling signal of the transformer is less than the voltage of the preset overcurrent threshold signal, a corresponding second overcurrent detection signal is generated, at this time the second overcurrent detection signal as an enabling signal can be used to control the inverter switch 600 to turn on.

[0060] In an embodiment, in combination with Figure 2 As shown in the figure, the inverter switch control circuit in the embodiment further includes a current detection circuit 500, which is used to generate a primary side current sampling signal by mutual inductance with the primary winding of the transformer.

[0061] In an embodiment, the current detection circuit 500 can be a mutual inductor or a Hall sensor.

[0062] In the embodiment, the current detection circuit 500 can transform the electromagnetic signal reflecting the current of the inverter power switch tube into a voltage signal (i.e. the primary side current sampling signal) convenient for processing and output to the overcurrent detection circuit 100.

[0063] In an embodiment, the overcurrent self-locking circuit 400 is further used to switch the locking mode of the overcurrent detection signal to a wave-by-wave disabling mode when the self-locking control signal is a first level (e.g. low level), and output a corresponding switch control signal to control the inverter switch 600 to turn on or turn off according to the overcurrent detection signal.

[0064] The overcurrent self-locking circuit 400 is further used to switch the locking mode of the overcurrent detection signal to the permanent disabling mode when the self-locking control signal is a second level (e.g. high level), and output a corresponding switch control signal to control the inverter switch 600 to be in an off state.

[0065] In an embodiment, referring to Figure 3As shown, the main control circuit 200 comprises a signal monitoring module 210 and a data calculation module 220.

[0066] The signal monitoring module 210 is configured to receive the overcurrent detection signal and monitor parameters of the overcurrent detection signal to generate overcurrent monitoring data; and the data calculation module 220 is configured to receive the overcurrent monitoring data and generate a lock mode control signal according to the overcurrent monitoring data.

[0067] In this embodiment, the signal monitoring module 210 can determine whether overcurrent occurs in the primary winding of the transformer, the number of times of overcurrent occurrence and the time of overcurrent occurrence by monitoring the level of the overcurrent detection signal, and generate overcurrent monitoring data based on the monitored parameters and output to the data calculation module 220. The data calculation module 220 can process the overcurrent monitoring data based on a set condition to generate a corresponding lock mode control signal to control the lock mode of the overcurrent detection signal in the overcurrent self-locking circuit 400.

[0068] In a specific application embodiment, the signal monitoring module 210 and the data calculation module 220 can be two independent processors, or can be integrated in the same processor.

[0069] In one embodiment, the signal monitoring module 210 is further configured to monitor the level of the overcurrent detection signal, determine that the current of the primary winding of the transformer is in an overcurrent state when the overcurrent detection signal is at a low level, and generate corresponding overcurrent monitoring data and send to the data calculation module 220.

[0070] In one embodiment, the signal monitoring module 210 is further configured to monitor the number of times of overcurrent and the time of overcurrent of the overcurrent detection signal, and generate corresponding overcurrent monitoring data and send to the data calculation module 220.

[0071] The data calculation module 220 is further configured to generate a corresponding mode control signal to switch the lock mode of the overcurrent detection signal to a permanent disable mode when the number of times of overcurrent in a preset time period reaches a preset number of times.

[0072] In this embodiment, the data calculation module 220 can process the overcurrent monitoring data based on a preset condition, so that the operation and lock of the inverter can be more scientific, reliable, reasonable and convenient. For example, if the overcurrent detection signal is at a low level in n inverter cycles in m consecutive inverter cycles, the data calculation module 220 generates a corresponding mode control signal to switch the lock mode of the overcurrent detection signal to a permanent disable mode, wherein n≤m, and m and n are positive integers.

[0073] In one embodiment, if the overcurrent detection signal is low in the last n inverter cycles, the data calculation module 220 generates a corresponding mode control signal to switch the locking mode of the overcurrent detection signal to the permanent disable mode.

[0074] In one embodiment, if the overcurrent detection signal is low in the last n inverter cycles, the data calculation module 220 generates a corresponding mode control signal to switch the locking mode of the overcurrent detection signal to the permanent disable mode.

[0075] By the data calculation module 220 processing the overcurrent monitoring data based on the preset condition to generate a corresponding mode control signal to switch the locking mode of the overcurrent detection signal, not only has the function of maintaining the inverter running in the wave-by-wave disable mode, but also has the function of guaranteeing the safe operation of the inverter in the permanent disable mode; and can be switched online between the two, better guaranteeing the high-performance operation of the inverter.

[0076] In one embodiment, referring to Figure 4 As shown in the figure, the overcurrent self-locking circuit 400 includes a first NAND gate U1, a second NAND gate U2, and a third NAND gate U3.

[0077] In this embodiment, the first input pin of the first NAND gate U1 is connected to the overcurrent detection circuit 100; the output pin of the first NAND gate U1, the first input pin of the second NAND gate U2, the first input pin of the third NAND gate U3, and the second input pin of the third NAND gate U3 are connected in common; the second input pin of the second NAND gate U2 is connected to the mode control circuit 300, and the output pin of the second NAND gate U2 is connected to the second input pin of the first NAND gate U1; the output pin of the third NAND gate U3 is used to output a switch control signal.

[0078] In this embodiment, the first NAND gate U1, the second NAND gate U2, and the third NAND gate U3 form a self-locking circuit, and the locking mode of the self-locking circuit is determined by the level of the second input pin of the second NAND gate U2; the mode control circuit 300 controls the switching of the locking mode of the overcurrent self-locking circuit 400 by providing a self-locking control signal VQ1C to the second input pin of the second NAND gate U2.

[0079] In one embodiment, referring to Figure 4 As shown in the figure, the mode control circuit 300 includes a switching transistor Q1 and a current limiting resistor R0.

[0080] In the embodiment, the first end of the current-limiting resistor R0 is connected to the power supply Vcc, the second end of the current-limiting resistor R0 and the first end of the switching transistor Q1 are commonly connected to the overcurrent self-locking circuit 400, the second end of the switching transistor Q1 is grounded, and the control end of the switching transistor Q1 is connected to the main control circuit 200.

[0081] In the embodiment, the switching transistor Q1, the current-limiting resistor R0 and the power supply Vcc form a signal conversion circuit, which is used to convert the lock mode control signal VOCLM into the corresponding self-locking control signal VQ1C. For example, if the lock mode control signal VOCLM is high, the switching transistor Q1 is turned on, and the self-locking control signal VQ1C is pulled low to the low level. If the lock mode control signal VOCLM is low, the switching transistor Q1 is turned off, and the self-locking control signal VQ1C is pulled up to the high level.

[0082] In one embodiment, the switching transistor Q1 can be an NPN type triode or an N type MOS tube.

[0083] In one embodiment, referring to FIG. 2, the overcurrent detection circuit 100 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a comparator U0. Figure 4

[0084] Specifically, the first end of the first resistor R1 is connected to the power supply Vcc, the second end of the first resistor R1 is connected to the first end of the second resistor R2, the second end of the second resistor R2 and the first end of the third resistor R3 are commonly connected to the positive input pin + of the comparator U0, the second end of the third resistor R3 is grounded, the inverting input pin - of the comparator U0 is connected to the current detection circuit 500, the ground pin of the comparator U0 is grounded, the power supply pin of the comparator U0 and the first end of the fourth resistor R4 are connected to the power supply Vcc, and the output pin of the comparator U0 and the second end of the fourth resistor R4 are commonly connected to the overcurrent self-locking circuit 400.

[0085] In the embodiment, the first resistor R1, the second resistor R2 and the third resistor R3 form a voltage dividing circuit, which is used to provide a preset overcurrent threshold signal. The voltage of the preset overcurrent threshold signal can be adjusted by adjusting the resistance ratio of the first resistor R1, the second resistor R2 and the third resistor R3, so as to adjust the overcurrent determination condition of the primary side current of the transformer. The comparator U0 and the fourth resistor R4 form a comparison circuit. When the voltage of the primary side current sampling signal VOCS is greater than the voltage of the preset overcurrent threshold signal VOCT, the comparison circuit outputs the low-level overcurrent detection signal VOC. When the voltage of the primary side current sampling signal VOCS is less than the voltage of the preset overcurrent threshold signal VOCT, the comparison circuit outputs the high-level overcurrent detection signal VOC.

[0086] In the following Figure 5 ​The signal timing diagram in FIG. 1A illustrates the working principle of the circuit in FIG. 1. Figure 4 The signal timing diagram in FIG. 1A illustrates the working principle of the circuit in FIG. 1.

[0087] In the signal timing diagram, the vertical axis Voltage represents voltage, and the horizontal axis Time represents time. As can be seen, the overcurrent detection circuit 100 compares the primary-side current sampling signal VOCS, which reflects the current of the power switch tube of the inverter, with the preset overcurrent threshold signal VOCT to generate an overcurrent detection signal VOC (VOC = 0, overcurrent; VOC = 1, no overcurrent). When the power switch tube has an overcurrent at time t1, the voltage of the primary-side current sampling signal VOCS is greater than the voltage of the preset overcurrent threshold signal VOCT, indicating that an overcurrent event occurs (OC Event), resulting in the overcurrent detection signal VOC being 0, the output signal VU3O of the first NAND gate U1 being 1, and the switch control signal VU4O output by the third NAND gate U3 being 0V. The inverter switch 600 is turned off by the switch control signal (no current flows through).

[0088] In the period (t3-t1) that follows, the lock mode control signal VOCLM received by the mode control circuit 300 is 0V (its digital signal can be represented as 0), causing the switching transistor Q1 to be turned off, and the self-lock control signal VQ1C generated by the mode control circuit 300 is at a high level (its digital signal can be represented as 1). At this time, the output signal VU2O of the second NAND gate U2 is 0, the lock mode of the overcurrent detection signal VOC in the overcurrent self-lock circuit 400 is switched to the permanent disable mode, causing the output signal VU3O of the first NAND gate U1 and the switch control signal VU4O to remain at 1 and 0, respectively, that is, the inverter switch 600 is in a permanently disabled off state due to the lock mode of the overcurrent self-lock circuit 400 being switched to the permanent disable mode (the inverter cannot maintain operation).

[0089] At time t3, the lock mode control signal VOCLM received by the mode control circuit 300 is at a high level (its digital signal can be represented as 1), causing the switching transistor Q1 to be saturated and turned on, and the self-lock control signal VQ1C is 0. The output signal VU2O of the second NAND gate U2 is 1, causing the output signal VU3O of the first NAND gate U1 to still follow the changes of the overcurrent detection signal VOC (at this time, no overcurrent event occurs, so the overcurrent detection signal VOC is 1). The lock mode of the overcurrent detection signal VOC in the overcurrent self-lock circuit 400 is switched to the wave-by-wave disable mode. The inverter switch 600 is in a wave-by-wave disable state of being turned off and turned on as the PWM duty cycle changes (the inverter can maintain operation) due to the non-self-locking state of the overcurrent detection signal of the overcurrent self-lock circuit 400.

[0090] At the t4 moment, the overcurrent detection circuit 100 detects the overcurrent event again, so that the overcurrent detection signal VOC is 0 during (t5-t4), the output signal VU3O of the first NAND gate U1 is 1, the switch control signal VU4O is 0, and the inverter switch 600 is turned off by the overcurrent disable signal. After the t5 moment, since the control signal VOCLM of the mode control circuit 300 is always 1, VU4O cannot be maintained as 0 but can only change (the switch control signal VU4O = 1, and the power switch tube changes from the disable state to the state that can be enabled and turned on) by synchronously following the overcurrent detection signal VOC (VOC = 1, no overcurrent). The signal monitoring module 210 monitors the occurrence, number of occurrences, and occurrence time of the overcurrent detection signal VOC to provide required variable inputs to the data calculation module 220 for real-time decision-making.

[0091] The embodiment of the present application also provides an inverter switch control method, which is combined with Figure 6 As shown in the figure, the inverter switch control method comprises steps S100 to S400.

[0092] In step S100, the primary side current sampling signal of the transformer is compared with a preset overcurrent threshold signal, and an overcurrent detection signal is output according to a comparison result.

[0093] In the embodiment, the primary side current sampling signal of the transformer is compared with the preset overcurrent threshold signal by providing the overcurrent detection circuit 100. Figure 1 As shown in the figure, the primary side current sampling signal of the transformer is compared with the preset overcurrent threshold signal by providing the overcurrent detection circuit 100, the detected inverter transformer primary side current (that is, the primary side current sampling signal) is compared with the set overcurrent threshold (that is, the preset overcurrent threshold signal) by the overcurrent detection circuit 100, and the corresponding overcurrent detection signal is generated according to the comparison result. The specific working principle of the overcurrent detection circuit 100 is shown in the above embodiment, which will not be described here.

[0094] In step S200, overcurrent monitoring data is generated by monitoring parameters of the overcurrent detection signal, and a lock mode control signal is generated according to the overcurrent monitoring data.

[0095] In the embodiment, the overcurrent monitoring data is obtained by providing the main control circuit 200, and the corresponding lock mode control signal is generated by processing the overcurrent monitoring data based on the preset mode switching condition. Figure 1 As shown in the figure, the overcurrent monitoring data is obtained by providing the main control circuit 200, and the corresponding lock mode control signal is generated by processing the overcurrent monitoring data based on the preset mode switching condition. The specific working principle of the main control circuit 200 is shown in the above embodiment, which will not be described here.

[0096] In step S300, a self-locking control signal is generated according to the lock mode control signal.

[0097] In the embodiment, the self-locking control signal is generated by providing the mode control circuit 300. Figure 1As shown, the mode control circuit 300 converts the lock mode control signal, and generates a self-lock control signal according to the lock mode control signal, and the specific working principle of the mode control circuit 300 is as shown in the above embodiment, which will not be repeated here.

[0098] In step S400, the lock mode of the overcurrent detection signal is switched according to the self-lock control signal, and a switch control signal is output according to the lock mode and the overcurrent detection signal to control the conduction and turn-off of the inverter switch.

[0099] In this embodiment, in combination with Figure 1 As shown, the overcurrent self-lock circuit 400 can switch the lock mode of the overcurrent detection signal according to the self-lock control signal, and output a switch control signal according to the lock mode and the overcurrent detection signal to control the conduction and turn-off of the inverter switch 600.

[0100] In the overcurrent self-lock circuit 400, the lock mode of the overcurrent detection signal includes a wave-by-wave disabling mode and a permanent disabling mode, the master control circuit 200 obtains overcurrent monitoring data by monitoring the parameters of the overcurrent detection signal, and processes the overcurrent monitoring data based on the preset mode switching condition to generate a corresponding lock mode control signal, and then the mode control circuit 300 converts the lock mode control signal into a corresponding self-lock control signal, to switch the lock mode of the overcurrent detection signal in the overcurrent self-lock circuit 400, and then the overcurrent self-lock circuit 400 processes the overcurrent detection signal based on the lock mode to generate a corresponding switch control signal, to realize the timely, effective and reliable turn-off (disabling) or conduction of the power switch tube, and ensure the stable and safe operation of the inverter.

[0101] The embodiment of the present application also provides an inverter power supply, which comprises an inverter switch and an inverter switch control circuit as described in any one of the above.

[0102] In one embodiment, the inverter power supply comprises an inverter switch and a switch driving circuit, and the switch driving circuit is used to perform the inverter switch control method as described above.

[0103] Compared with the prior art, the embodiment of the present application has the beneficial effects that: the primary side current sampling signal of the transformer is compared with the preset overcurrent threshold signal through the overcurrent detection circuit, and an overcurrent detection signal is output according to the comparison result; then the parameters of the overcurrent detection signal are monitored by the main control circuit to generate overcurrent monitoring data, and a lock mode control signal is generated according to the overcurrent monitoring data, the mode control circuit generates a self-locking control signal according to the lock mode control signal to control the lock mode of the overcurrent detection signal to switch between the wave-by-wave disabling mode and the permanent disabling mode, and the overcurrent self-locking circuit outputs a switch control signal according to the lock mode and the overcurrent detection signal to control the conduction and shutdown of the inverter switch, so that the power switch tube can switch the working state according to the application scene, while the continuous operation and safe operation of the power switch tube are ensured.

[0104] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. An inverter switch control circuit, connected to an inverter switch, characterized in that, The application relates to an overcurrent detection circuit, a main control circuit, a mode control circuit and an overcurrent self-locking circuit. The overcurrent detection circuit is used for comparing a primary winding current sampling signal of a transformer with a preset overcurrent threshold signal and outputting an overcurrent detection signal according to a comparison result. The main control circuit is used for monitoring parameters of the overcurrent detection signal to generate overcurrent monitoring data and generating a lock mode control signal according to the overcurrent monitoring data. The mode control circuit is connected with the main control circuit and is used for generating a self-locking control signal according to the lock mode control signal. The overcurrent self-locking circuit is connected with the overcurrent detection circuit, the mode control circuit and an inverter switch and is used for switching a lock mode of the overcurrent detection signal according to the self-locking control signal and outputting a switch control signal according to the lock mode and the overcurrent detection signal to control on and off of the inverter switch; wherein the lock mode comprises a wave-by-wave disabling mode and a permanent disabling mode; in the permanent disabling mode, the inverter switch is permanently turned off; in the wave-by-wave disabling mode, the inverter switch is turned on or turned off according to the overcurrent detection signal.

2. The inverter switch control circuit of claim 1, wherein The inverter switch control circuit further comprises a current detection circuit which is used for sampling a current of the primary winding of the transformer to generate the primary winding current sampling signal. When the self-locking control signal is a first level, the overcurrent self-locking circuit is used for switching the lock mode of the overcurrent detection signal to the wave-by-wave disabling mode and outputting a corresponding switch control signal to control the inverter switch to be turned on or turned off according to the overcurrent detection signal.

3. The inverter switch control circuit of claim 1, wherein When the self-locking control signal is a second level, the overcurrent self-locking circuit is used for switching the lock mode of the overcurrent detection signal to the permanent disabling mode and outputting a corresponding switch control signal to control the inverter switch to be turned off. The main control circuit comprises a signal monitoring module and a data calculation module.

4. The inverter switch control circuit of claim 1, wherein The signal monitoring module is used for receiving the overcurrent detection signal and monitoring parameters of the overcurrent detection signal to generate overcurrent monitoring data. The data calculation module is used for receiving the overcurrent monitoring data and generating a lock mode control signal according to the overcurrent monitoring data. The signal monitoring module is further used for monitoring a level of the overcurrent detection signal, determining that a current of the primary winding of the transformer is in an overcurrent state when the overcurrent detection signal is a low level and generating corresponding overcurrent monitoring data and sending the overcurrent monitoring data to the data calculation module.

5. The inverter switch control circuit as described in claim 4, characterized in that, The signal monitoring module is further used for monitoring an overcurrent frequency and an overcurrent time of the overcurrent detection signal and generating corresponding overcurrent monitoring data and sending the overcurrent monitoring data to the data calculation module.

6. The inverter switch control circuit of claim 4, wherein, The data calculation module is further used for generating a corresponding mode control signal to switch the lock mode of the overcurrent detection signal to the permanent disabling mode when the overcurrent frequency reaches a preset frequency within a preset time period. The overcurrent self-locking circuit comprises a first NAND gate, a second NAND gate and a third NAND gate.

7. The inverter switch control circuit of claim 1, wherein A first input pin of the first NAND gate is connected with the overcurrent detection circuit. ​ An output pin of the first NAND gate, a first input pin of the second NAND gate, a first input pin of the third NAND gate, and a second input pin of the third NAND gate are connected together; A second input pin of the second NAND gate is connected to the mode control circuit, and an output pin of the second NAND gate is connected to a second input pin of the first NAND gate; An output pin of the third NAND gate is used to output the switch control signal.

8. The inverter switch control circuit of claim 1, wherein, The mode control circuit comprises a switching switch tube and a current-limiting resistor. A first end of the current-limiting resistor is connected to a power supply, a second end of the current-limiting resistor and a first end of the switching switch tube are connected together to the overcurrent self-locking circuit, a second end of the switching switch tube is grounded, and a control end of the switching switch tube is connected to the main control circuit.

9. An inverter switching control method of an inverter switching control circuit as claimed in any one of claims 1 to 8, characterized by, Comprising: comparing a primary side current sampling signal of a transformer with a preset overcurrent threshold signal, and outputting an overcurrent detection signal according to a comparison result; monitoring parameters of the overcurrent detection signal to generate overcurrent monitoring data, and generating a lock mode control signal according to the overcurrent monitoring data; generating a self-locking control signal according to the lock mode control signal; switching a lock mode of the overcurrent detection signal according to the self-locking control signal, and outputting a switch control signal according to the lock mode and the overcurrent detection signal to control conduction and turn-off of the inverter switch; wherein the lock mode comprises a wave-by-wave disable mode and a permanent disable mode.

10. An inverter power supply, characterized by comprising: Comprising: an inverter switch, and an inverter switch control circuit according to any one of claims 1-8; or the inverter power supply comprises an inverter switch and a switch driving circuit, and the switch driving circuit is used to perform the inverter switch control method according to claim 9.

Images