Overcurrent protection device and power supply

Abstract

The application provides an overcurrent protection device and a power supply. The overcurrent protection device comprises a first protection module and a second protection module. The first protection module is used for generating a first locking signal when a first state signal is received, and sending the first locking signal to a power switch module to control the locking of each power switch in the power switch module. The first state signal is used for representing input overcurrent or output overcurrent of a power conversion device. The second protection module is used for maintaining the first state signal for a first time length, generating a second locking signal, and sending the second locking signal to a control module to make the control module control the locking of each power switch in the power switch module when the first state signal is received. The first time length is not less than a signal detection period of the control module. The application can improve the reliability of overcurrent protection of the power conversion device.

Description

Technical Field

[0001] This invention relates to the field of overcurrent protection technology, and in particular to an overcurrent protection device and power supply. Background Technology

[0002] For power supplies that include a converter module, the converter module is generally composed of power switches. The duty cycle of the power switches is controlled by a PWM (Pulse Width Modulation) wave to achieve the converter function. Generally, to improve the reliability of the power supply and prevent overcurrent damage, overcurrent protection measures are implemented. For example, when an overcurrent signal is detected, the power switch is pulse-locked by controlling the PWM wave to disconnect the circuit and prevent overcurrent damage to components.

[0003] However, single overcurrent protection methods have low reliability and there is a certain probability that the overcurrent protection will fail due to reasons such as program crashes or logic errors, thereby damaging the power supply and causing safety accidents. Summary of the Invention

[0004] This invention provides an overcurrent protection device and power supply to address the problem that single overcurrent protection methods have low reliability and are prone to failure due to program crashes, logic errors, or other reasons, which could damage the power supply and cause safety accidents.

[0005] In a first aspect, the present invention provides an overcurrent protection device applied to a power conversion device, the power conversion device including a power switch module and a control module, the power switch module being controlled by the control module; the overcurrent protection device includes a first protection module and a second protection module.

[0006] The first protection module is used to generate a first blocking signal when it receives a first state signal, and send the first blocking signal to the power switch module to control the blocking of each power switch in the power switch module. The first state signal is used to characterize the input overcurrent or output overcurrent of the power conversion device.

[0007] The second protection module is used to maintain the first status signal for a first duration upon receiving the first status signal, generate a second blocking signal, and send the second blocking signal to the control module so that the control module controls the blocking of each power switch in the power switch module; wherein the first duration is not less than the signal detection period of the control module.

[0008] In one possible implementation, the second protection module includes a signal transmission unit and a signal holding unit;

[0009] The signal holding unit is used to hold the first state signal for a first duration when a first state signal is received, and to send the first state signal to the signal transmission unit.

[0010] The signal transmission unit is used to generate a second latching signal when it receives a first state signal sent by the signal holding unit, and send the second latching signal to the control module, or forward the first state signal sent by the signal holding unit to the control module so that the control module controls the latching of each power switch in the power switch module.

[0011] In one possible implementation, the signal transmission unit includes an isolation subunit;

[0012] The isolation subunit is used to electrically isolate the signal holding unit and the control module.

[0013] In one possible implementation, the first state signal is either a low-level active signal or a high-level active signal;

[0014] The signal holding unit is used to extend the falling edge and / or rising edge of the first state signal to hold the first state signal for a first duration.

[0015] In one possible implementation, the first state signal is a low-level active signal; the signal holding unit includes a first holding resistor, a second holding resistor, a delay resistor, and a delay capacitor;

[0016] The first end of the delay resistor is connected to the second end of the first holding resistor and the second end of the second holding resistor, respectively. The second end is connected to the second end of the delay capacitor and the signal transmission unit, respectively. The first end of the first holding resistor is connected to the first end of the second protection module. The first end of the second holding resistor and the first end of the delay capacitor are both connected to the ground terminal.

[0017] Alternatively, the signal holding unit may also include a delay diode;

[0018] The positive terminal of the delay diode is connected to the second terminal of the delay resistor, and the negative terminal is connected to the first terminal of the delay resistor.

[0019] In one possible implementation, the overcurrent protection device further includes a first detection module, wherein a first status signal is used to characterize the three-phase output overcurrent of the power conversion device;

[0020] The first detection module is used to generate a first status signal when an overcurrent is detected in at least one phase output of the power conversion device, and to send the first status signal to the signal holding unit and the first protection module respectively.

[0021] In one possible implementation, the first detection module includes a first resistor, a second resistor, a third resistor, a first AND gate, and a second AND gate;

[0022] The first AND gate has its first input terminal connected to the second terminal of the first resistor, its second input terminal connected to the second terminal of the second resistor, and its output terminal connected to the first input terminal of the second AND gate; the first terminal of the first resistor is used to connect to the first phase overcurrent detection terminal of the power conversion device, and the first terminal of the second resistor is used to connect to the second phase overcurrent detection terminal of the power conversion device.

[0023] The second AND gate has its second input terminal connected to the second terminal of the third resistor, and its output terminal connected to the signal holding unit and the first protection module, respectively; the first terminal of the third resistor is connected to the third phase overcurrent detection terminal of the power conversion device.

[0024] In one possible implementation, the overcurrent protection device further includes a second detection module; the second detection module is connected between the first detection module and the first protection module, and the second detection module is also used to connect to the control module;

[0025] The control module is further configured to: generate a PWM lock signal upon receiving a first status signal and send the PWM lock signal to the second detection module; and / or generate a programming lock signal upon detecting an external programming signal and send the programming lock signal to the second detection module; and / or generate a first power supply abnormality signal upon detecting a power supply abnormality in the control module and send the first power supply abnormality signal to the second detection module; and / or generate a second power supply abnormality signal upon detecting a power supply abnormality in either the first or second detection module and send the second power supply abnormality signal to the second detection module; and / or generate a bus abnormality signal upon detecting an overvoltage on the DC bus of the power conversion device and send the bus abnormality signal to the second detection module.

[0026] The second detection module is used to send the first status signal to the first protection module when it receives the first status signal; or, when it detects the PWM lock signal, the programming signal, the first power supply abnormality signal, the second power supply abnormality signal and / or the bus abnormality signal, it generates the second status signal and sends the second status signal to the first protection module.

[0027] The first protection module is also used to generate a third blocking signal when it receives the second status signal, and send the third blocking signal to the power switch module to control the blocking of each power switch in the power switch module.

[0028] In one possible implementation, the second detection module includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a third AND gate, a fourth AND gate, a fifth AND gate, a sixth AND gate, a seventh AND gate, a first capacitor, and a second capacitor;

[0029] The third AND gate has its first input connected to the first detection module, its second input connected to the second end of the fourth resistor, and its output connected to the first input of the fifth AND gate; the first end of the fourth resistor is connected to the control module.

[0030] The fourth AND gate has its first input connected to the second terminal of the fifth resistor, its second input connected to the second terminal of the sixth resistor, and its output connected to the second input of the fifth AND gate. The first terminals of both the fifth and sixth resistors are connected to the control module, and the output of the fifth AND gate is connected to the first input of the seventh AND gate.

[0031] The sixth AND gate has its first input terminal connected to the second terminal of the seventh resistor, the second terminal of the ninth resistor, and the first terminal of the first capacitor, respectively. Its second input terminal is connected to the second terminal of the eighth resistor, the second terminal of the tenth resistor, and the first terminal of the second capacitor, respectively. Its output terminal is connected to the second input terminal of the seventh AND gate. The first terminals of the seventh resistor and the eighth resistor are both connected to the control module. The output terminal of the seventh AND gate is connected to the first protection module. The first terminals of the ninth resistor and the tenth resistor are both connected to the power supply terminal. The second terminals of the first capacitor and the second terminals of the second capacitor are both connected to the ground terminal.

[0032] Secondly, the present invention provides a power supply, including the overcurrent protection device and power conversion device as described in the first aspect above.

[0033] This invention provides an overcurrent protection device applied to a power conversion device including a power switch module and a control module. The overcurrent protection device includes a first protection module and a second protection module. By setting up the first and second protection modules, each switch of the power switch is simultaneously controlled and locked when the power conversion device experiences an overcurrent. The second protection module maintains the first state signal, ensuring reliable detection of the overcurrent and preventing a situation where the first protection module detects an overcurrent while the second protection module fails to detect it. Compared to using only one overcurrent protection method, the first protection module directly sends the first lockout signal to the power switch module, resulting in a shorter signal transmission process and faster protection response. The second protection module sends the second lockout signal to the control module, which, being the same module used to control the power switch, performs the lockout action, ensuring reliable locking of the power switch and improving the stability of the overcurrent protection. Therefore, both protection modules can provide overcurrent protection, acting as backups, independent of each other, and without interference, effectively improving the reliability of overcurrent protection in the power conversion device. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure of an overcurrent protection device provided in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the circuit structure of a signal holding unit provided in an embodiment of the present invention;

[0038] Figures 4A to 4C This is a schematic diagram illustrating different holding durations provided in embodiments of the present invention;

[0039] Figure 5 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention;

[0040] Figure 6 This is a circuit connection diagram of the first detection module provided in an embodiment of the present invention;

[0041] Figure 7 This is a schematic diagram of the structure of the fourth overcurrent protection device provided in the embodiments of the present invention;

[0042] Figure 8 This is a circuit connection diagram of the second detection module provided in an embodiment of the present invention;

[0043] Figure 9 This is a schematic diagram of the circuit structure of the first protection module provided in an embodiment of the present invention. Detailed Implementation

[0044] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0045] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0046] The implementation of the present invention will be described in detail below with reference to the accompanying drawings:

[0047] Figure 1 This is a schematic diagram of an overcurrent protection device provided in an embodiment of the present invention. (Refer to...) Figure 1 In this embodiment of the invention, the overcurrent protection device 10 is applied to a power conversion device 20. The power conversion device 20 includes a power switch module 201 and a control module 202. The power switch module 201 is controlled by the control module 202, which controls the operation of each power switch in the power switch module 201. For example, the control module 202 controls the duty cycle of each power switch through a PWM wave, thereby controlling the operation of each power switch.

[0048] The overcurrent protection device 10 of this embodiment includes a first protection module 101 and a second protection module 102. The first protection module 101 has a first end connected to the first end of the second protection module 102, and a second end for direct connection to a power switch module 201. The first end of the first protection module 101 is also used for connection to a power conversion device 20. The second protection module 102 has a first end for connection to the power conversion device 20 and a second end for connection to a control module 202.

[0049] The first protection module 101 is used to generate a first blocking signal when it receives a first status signal, and send the first blocking signal to the power switch module 202 to control the blocking of each power switch in the power switch module 201. The first status signal is used to characterize the input overcurrent or output overcurrent of the power conversion device 20.

[0050] The second protection module 102 is used to maintain the first status signal for a first duration upon receiving the first status signal, generate a second blocking signal, and send the second blocking signal to the control module 202 so that the control module 202 controls the blocking of each power switch in the power switch module 201; wherein the first duration is not less than the signal detection period of the control module 202.

[0051] Optionally, the power conversion device 20 may include an overcurrent detection module for detecting input or output overcurrent, meaning the power conversion device 20 can directly output a first state signal. The first state signal can be output by the overcurrent detection module in the power conversion device 20 or by the control module 202; the specific output can be determined based on actual conditions, and this embodiment of the invention does not impose any limitations.

[0052] Optionally, the first latching signal can be directly applied to each power switch in the power module 201 to control the latching of each power switch. For example, it can be directly applied to the gate of each power switch to achieve a turn-off function. The second latching signal is used to indirectly control the latching of each switch in the power switch module 201 through the control module 202. For example, the second latching signal can instruct the control module 202 to generate a PWM wave latching signal to control the duty cycle of each power switch to zero, thereby achieving the purpose of turning off each power switch.

[0053] Optionally, the second protection module 102 is also used to ensure that the control module 202 can promptly control the switching on and off of each power source. The first duration can be set according to the actual situation.

[0054] Specifically, the first blocking signal generated by the first protection module 101 directly acts on the power switch module 201, and the second blocking signal generated by the second protection module 102 indirectly acts on the power switch module 201 through the control module 202. The overcurrent protection action time of the first protection module 101 is faster than the overcurrent protection action time of the second protection module 102, and also faster than the action time of the control module 202.

[0055] To prevent the first protection module 101 from directly blocking all power switches when an overcurrent occurs in the power conversion device 20, thus preventing the power conversion device 20 from outputting a first status signal and causing the control module 202 to fail to detect the second blocking signal and control all power switches to operate normally (i.e., the control module 202 experiences an overcurrent detection failure), and to prevent the first protection module 101 from blocking all power switches while the control module 202 controls them to operate normally, repeated switching may occur if the overcurrent cause is not eliminated. This could damage the lifespan of the power switches and potentially cause the power conversion device to malfunction, leading to a safety accident. Therefore, the second protection module 102 needs to maintain the first status signal for a first duration to ensure that the control module 202 can reliably detect the second blocking signal within the detection cycle.

[0056] This embodiment of the invention provides overcurrent protection for the power conversion device 20 simultaneously through a first protection module 101 and a second protection module 102. Compared to existing overcurrent protection methods with only one method, the first protection module 101 directly sends a first blocking signal to the power switch, resulting in a shorter signal transmission process and faster protection response. The second protection module 102 sends a second blocking signal to the control module 202. Since the control module 202, which is originally used to control the power switch, performs the blocking action on the power switch, it ensures that the power switch can be reliably blocked, improving the stability of overcurrent protection. Therefore, both protection modules can play the role of overcurrent protection, backing each other up, operating independently and without affecting each other, effectively improving the reliability of overcurrent protection for the power conversion device 20. Simultaneously, to reduce the complexity of signal control and meet the requirements of device layout, while ensuring that the control module 202 can effectively monitor the second blocking signal, the second protection module 102 can maintain the first state signal for a first duration, effectively improving the operational reliability of the overcurrent protection device 10.

[0057] See Figure 2 This illustrates a structural schematic diagram of another overcurrent protection device provided in an embodiment of the present invention. Figure 2 As shown, in some embodiments of the present invention, the second protection module 102 includes a signal transmission unit 1021 and a signal holding unit 1022;

[0058] The signal holding unit 1021 is used to hold the first state signal for a first duration when it receives the first state signal, and to send the first state signal to the signal transmission unit 1022.

[0059] Optionally, the first state signal can be a low-level active signal or a high-level active signal. A signal holding unit is used to extend the falling edge and / or rising edge of the first state signal to hold the first state signal for a first duration.

[0060] Specifically, when the first state signal is a low-level active signal, the signal holding unit is used to extend the falling edge of the first state signal to hold the first state signal for a first duration. Alternatively, the signal holding unit is used to extend the rising edge of the first state signal to hold the first state signal for a first duration. Alternatively, the signal holding unit is used to extend both the rising and falling edges of the first state signal to hold the first state signal for a first duration. The specific choice can be made according to the actual situation. The situation when the first state signal is a high-level active signal is similar to the above, and will not be elaborated further in this embodiment.

[0061] For example, see Figure 3 This illustrates a circuit structure diagram of a signal holding unit provided in an embodiment of the present invention. Figure 3As shown, the first state signal is a low-level active signal; the signal holding unit includes a first holding resistor R01, a second holding resistor R02, a delay resistor RT, and a delay capacitor CT;

[0062] The first end of the delay resistor RT is connected to the second end of the first holding resistor R01 and the second end of the second holding resistor R02, and the second end is connected to the second end of the delay capacitor CT and the signal transmission unit 1022, respectively. The first end of the first holding resistor R01 is connected to the first end of the second protection module 102, and the first end of the second holding resistor R02 and the first end of the delay capacitor CT are both connected to the ground terminal GND.

[0063] Optionally, the delay resistor RT and the delay capacitor CT constitute an RC delay circuit, which can extend both the rising and falling edges of the first state signal to maintain the first state signal for a first duration.

[0064] See Figure 3 In some embodiments of the present invention, the signal holding unit 1021 further includes a delay diode DT;

[0065] The positive terminal of the delay diode DT is connected to the second terminal of the delay resistor RT, and the negative terminal is connected to the first terminal of the delay resistor RT.

[0066] Optionally, by connecting a diode in parallel with the delay resistor RT, the rising edge of the first state signal can be extended to maintain the first state signal for a first duration.

[0067] Optionally, the holding time of the first duration can be adjusted by adjusting the values ​​of the delay resistor RT and the delay capacitor CT, without affecting the protection action of the first protection module.

[0068] For example, Figures 4A to 4C This is a schematic diagram illustrating different holding times provided in embodiments of the present invention. Figure 4A The duration of the first state signal held by the signal holding unit 1021 without the signal holding unit is shown as T1. Figure 4B The first state signal holding time, T2, is shown when the signal holding unit 1021 is added but the delay diode DT is not increased. Figure 4C The diagram illustrates the holding time (T3) of the first state signal when an additional signal holding unit 1021 and a delay diode DT are added. As shown above, T1 < T3 < T2, and a suitable signal delay strategy can be selected based on the actual situation. The signal holding unit 1021 provided in this embodiment can be applied to signal holding in various scenarios, improving the applicability of power conversion devices and demonstrating high practicality.

[0069] In this embodiment of the invention, by configuring the resistance value of the delay resistor RT and the capacitance value of the delay capacitor CT to ensure that the holding time T3 meets the requirements of the first duration, a delay diode DT is added. Compared with the embodiment without the delay diode DT, this changes the charging and discharging characteristics of the delay capacitor CT, reduces the falling edge time of the first state signal, and enables the second latching signal to reach the control module 202 in a timely manner, thus improving the response speed of the overcurrent protection.

[0070] The signal transmission unit 1022 is used to generate a second lockout signal when it receives a first status signal sent by the signal holding unit 1021, and send the second lockout signal to the control module 202, or forward the first status signal sent by the signal holding unit 1021 to the control module 202 so that the control module 202 controls the locking and unlocking of each power switch in the power switch module 201.

[0071] Optionally, the signal transmission unit 1022 can directly forward the first status signal sent by the signal holding unit 1021 to the control module 202, so that the control module 202 controls the locking and unlocking of each power switch in the power switch module 201. Alternatively, the signal transmission unit can also generate a second locking signal based on the first status signal sent by the holding unit 1021, and send the second locking signal to the control module 202, so that the control module 202 controls the locking and unlocking of each power switch in the power switch module 201.

[0072] For example, the signal transmission unit 1022 may include an isolation subunit. The isolation subunit is used to electrically isolate the signal between the signal holding unit and the control module.

[0073] Optionally, the signal isolation subunit can be composed of an optocoupler isolation circuit, used to convert the first state signal isolation into a second blocking signal, thereby achieving signal isolation between the second protection module 102 and the control module 202 and realizing anti-interference. This embodiment of the invention improves the overall anti-interference performance through the signal isolation subunit, which is beneficial to improving the operational reliability of the overcurrent protection device and the power conversion device.

[0074] See Figure 5 This illustrates a structural schematic diagram of another overcurrent protection device provided in an embodiment of the present invention. Figure 5 As shown, the overcurrent protection device 10 also includes a first detection module 103, and the first status signal is used to characterize the three-phase output overcurrent of the power conversion device 20;

[0075] The first detection module 103 has a first end connected to the power conversion device 20, a second end connected to the first protection module 101, and a third end connected to the signal holding unit 1021.

[0076] The first detection module 103 is used to generate a first status signal when an overcurrent is detected in at least one phase output of the power conversion device 10, and send the first status signal to the signal holding unit 1021 and the first protection module 101 respectively.

[0077] Optional, see Figure 6 This actually shows a circuit connection diagram of the first detection module provided in an embodiment of the present invention. Figure 6 As shown, the first detection module includes a first resistor R1, a second resistor R2, a third resistor R3, a first AND gate IC1, and a second AND gate IC2;

[0078] The first AND gate IC1 has its first input terminal connected to the second terminal of the first resistor R1, its second input terminal connected to the second terminal of the second resistor R2, and its output terminal connected to the first input terminal of the second AND gate IC2; the first terminal of the first resistor R1 is used to connect to the first phase overcurrent detection terminal of the power conversion device 10, and the first terminal of the second resistor R2 is used to connect to the second phase overcurrent detection terminal of the power conversion device 10.

[0079] The second AND gate IC2 has its second input terminal connected to the second terminal of the third resistor R3, and its output terminal connected to the signal holding unit 1021 and the first protection module 101, respectively; the first terminal of the third resistor R3 is connected to the third phase overcurrent detection terminal of the power conversion device 10.

[0080] Optionally, in this embodiment of the invention, the first state signal can be a low-level active signal, used to characterize at least one phase output overcurrent of the power conversion device 20. When the output of the power conversion device 20 is not overcurrent, the overcurrent detection terminal corresponding to the output that has experienced overcurrent outputs a low level, and the overcurrent detection terminals corresponding to the other outputs that have not experienced overcurrent output a high level; when the output of the power conversion device 20 is not overcurrent, the first phase overcurrent detection terminal, the second phase overcurrent detection terminal, and the third phase overcurrent detection terminal all output a high level. Wherein, Linv_A represents the first phase overcurrent signal, Linv_B represents the second phase overcurrent signal, and Linv_C represents the third phase overcurrent signal.

[0081] See Figure 7 This illustrates a structural schematic diagram of the fourth overcurrent protection device provided in an embodiment of the present invention. Figure 7 As shown, the overcurrent protection device 10 of this embodiment may further include a second detection module 104; the second detection module 104 is connected between the first detection module 103 and the first protection module 101, and the second detection module 104 is also used to connect to the control module 202.

[0082] The control module 202 is further configured to generate a PWM lock signal PWM_EN upon receiving a first status signal and send the PWM lock signal PWM_EN to the second detection module; and / or, generate a programming lock signal PWM_DELAY upon detecting an external programming signal and send the programming lock signal PWM_DELAY to the second detection module 104; and / or, generate a first power supply abnormality signal XRS_DSP upon detecting a power supply abnormality in the control module 202 and send the first power supply abnormality signal XRS_DSP to the second detection module 104; and / or, generate a second power supply abnormality signal XRS_DR upon detecting a power supply abnormality in the first detection module 103 or the second detection module 104 and send the second power supply abnormality signal XRS_DR to the second detection module 104; and / or, generate a bus abnormality signal upon detecting an overvoltage on the DC bus of the power conversion device and send the bus abnormality signal to the second detection module.

[0083] The second detection module 104 is used to send the first status signal to the first protection module 101 when it receives the first status signal; or, when it detects the PWM lock signal PWM_EN, the programming signal PWM_DELAY, the first power supply abnormality signal XRS_DSP, the second power supply abnormality signal XRS_DR and / or the bus abnormality signal Vbus, it generates a second status signal and sends the second status signal to the first protection module 101.

[0084] The first protection module 101 is also used to generate a third lockout signal when it receives the second status signal, and send the third lockout signal to the power switch module 201 to control the lockout of each power switch in the power switch module 201.

[0085] Optionally, in order to improve the working reliability of the power conversion device 20, it is necessary to prevent the working logic of the first protection module 101 from being accidentally triggered under certain circumstances. Therefore, it is necessary to lock the first protection module 101 under specific circumstances, that is, the first protection module needs to control the locking and unlocking of each power switch in the power switch module 201.

[0086] Specifically, when a new control program is programmed into the power conversion device 20, a programming signal is generated. During programming, the control module 202 generates the programming signal PWM_DELAY. When the control module 202 detects the first status signal, the control module 201 generates the PWM lock signal PWM_EN. When the power supply to the control module 201 is abnormal, the control module 201 generates the first power supply abnormality signal XRS_DSP. When the power supply to either the first detection module 103 or the second detection module is abnormal, the control module 201 generates the second power supply abnormality signal XRS_DR. When there is an overvoltage on the DC bus of the power conversion device 20, the control module 201 generates the bus abnormality signal Vbus.

[0087] Among them, the PWM lockout signal PWM_EN, the programming signal PWM_DELAY, the first power supply abnormality signal XRS_DSP, the second power supply abnormality signal XRS_DR, and the bus abnormality signal Vbus are all active low-level signals. That is, when at least one of the above five signals is triggered, the first protection module 101 generates a third lockout signal to control the power switch module 201 to open and close.

[0088] Optionally, the PWM lock signal PWM_EN can be held for 3ms, after which it will automatically unlock and change from low to high.

[0089] See Figure 8 This illustrates a schematic diagram of the circuit structure of the second detection module according to an embodiment of the present invention. Figure 8 As shown, the second detection module 104 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a third AND gate IC3, a fourth AND gate IC4, a fifth AND gate IC5, a sixth AND gate IC6, a seventh AND gate IC7, a first capacitor C1, and a second capacitor C2.

[0090] The third AND gate IC3 has its first input connected to the first detection module 103, its second input connected to the second end of the fourth resistor R4, and its output connected to the first input of the fifth AND gate IC5. The first end of the fourth resistor R4 is connected to the control module 201. Specifically, the first input of the third AND gate IC3 is connected to the output of the second AND gate IC2, and the first end of the fourth resistor R4 can be used to receive the bus abnormality signal Vbus.

[0091] The fourth AND gate IC4 has its first input connected to the second terminal of the fifth resistor R5, its second input connected to the second terminal of the sixth resistor R6, and its output connected to the second input terminal of the fifth AND gate IC5. The first terminals of both the fifth resistor R5 and the sixth resistor R6 are connected to the control module 201. The output terminal of the fifth AND gate IC5 is connected to the first input terminal of the seventh AND gate IC7. Specifically, the first terminal of the fifth resistor R5 can be used to receive the first power supply abnormality signal XRS_DSP, and the first terminal of the sixth resistor R6 can be used to receive the second power supply abnormality signal XRS_DR.

[0092] The sixth AND gate IC6 has its first input terminal connected to the second terminals of the seventh resistor R7, the ninth resistor R9, and the first capacitor C1, respectively. Its second input terminal is connected to the second terminals of the eighth resistor R8, the tenth resistor R10, and the second capacitor C2, respectively. Its output terminal is connected to the second input terminal of the seventh AND gate IC7. The first terminals of the seventh resistor R7 and the eighth resistor R8 are both connected to the control module 201. The output terminal of the seventh AND gate IC7 is connected to the first protection module 103. The first terminals of the ninth resistor R9 and the tenth resistor R10 are both connected to the power supply terminal VCC. The second terminals of the first capacitor C1 and the second capacitor C2 are both connected to the ground terminal GND. The first terminal of the seventh resistor R7 can be used to receive the PWM lock signal PWM_EN, and the first terminal of the eighth resistor R8 can be used to receive the programming signal PWM_DELAY.

[0093] Optionally, the first AND gate IC1, the second AND gate IC2, the third AND gate IC3, and the fourth AND gate IC4 can be four AND gates on the same logic gate chip. The fifth AND gate IC5, the sixth AND gate IC6, and the seventh AND gate IC7 can be three AND gates on the same logic gate chip. The ground terminal GND can be 0V, and the power supply terminal VCC can be 3.3V. The specific configuration can be determined based on the actual situation.

[0094] See Figure 9 This illustrates a schematic diagram of the circuit structure of the first protection module provided in an embodiment of the present invention. Figure 9 As shown, the first protection module 103 may include an eleventh resistor R11, a twelfth resistor R12, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a first diode D1, and a second diode D2.

[0095] The cathode of the first diode D1 is connected to the first terminal of the eleventh resistor R11, the anode of the second diode D2, the first terminal of the twelfth resistor R12, and the second detection module 104, respectively. The anode of the first diode D1 is connected to the second terminal of the eleventh resistor R11, the first terminal of the third capacitor C3, and the power switch module 201, respectively. The second terminal of the third capacitor C3 is connected to the ground terminal GND. The cathode of the first diode D1 can be connected to the output terminal of the seventh AND gate IC7, and the anode of the first diode D1 can be connected to each power switch in the power switch module 201 in the vertical position. The power switches in the vertical position can be controlled through the anode of the first diode D1.

[0096] The cathode of the second diode D2 is connected to the second terminal of the twelfth resistor R12, the first terminal of the fourth capacitor C4, the first terminal of the fifth capacitor C5, and the power switch module 201, respectively. The second terminals of the fourth capacitor C4 and the fifth capacitor C5 are both connected to the ground terminal GND. The cathode of the second diode D1 can be connected to each power switch in the power switch module 201 that is in the horizontal tube position. The cathode of the second diode D2 can control the power switches in the horizontal tube position.

[0097] Optionally, the sum of the capacitance values ​​of the fourth capacitor C4 and the fifth capacitor C5 is not equal to the capacitance value of the third capacitor C3. This can prevent the power switch in the horizontal tube position and the power switch in the vertical tube position from being turned on at the same time, thereby improving the working reliability of the power switch module.

[0098] For example, the following is combined with Figure 6 and Figure 8 The operation of the overcurrent protection device 10 according to an embodiment of the present invention will be described. The PWM lock signal PWM_EN, the programming signal PWM_DELAY, the first power supply abnormality signal XRS_DSP, the second power supply abnormality signal XRS_DR, the bus abnormality signal Vbus, the first phase overcurrent signal Linv_A, the second phase overcurrent signal Linv_B, and the third phase overcurrent signal Linv_C are all active low-level signals.

[0099] Each of these signals normally indicates the occurrence of the corresponding event when it is at a low level. For example, when there is an overcurrent at the first phase output of the power conversion device 20, Linv_A is at a low level; otherwise, Linv_A is at a high level. The same applies to other signals.

[0100] For example, such as Figure 6 As shown, when at least one of Linv_A, Linv_B, and Linv_C is a low-level signal, the second AND gate IC2 outputs a low level, triggering both the second protection module 102 and the first protection module 101 to work, which can simultaneously control the locking and unlocking of each power switch in the power switch module.

[0101] When Linv_A, Linv_B, and Linv_C are all at high level, the second AND gate IC2 outputs a high level, and neither the first protection module 101 nor the second protection module 102 works.

[0102] For example, such as Figure 8 As shown, when at least one of Linv_A, Linv_B, Linv_C, PWM_EN, PWM_DELAY, XRS_DSP, XRS_DR, and Vbus is a low-level signal, the seventh AND gate IC7 outputs a low level, triggering the first protection module 101 to work, and locking each power switch in the power switch module 201.

[0103] When at least one of Linv_A, Linv_B, and Linv_C is a low-level signal, both the second AND gate IC2 and the seventh AND gate IC7 output a low level, triggering both the second protection module 102 and the first protection module 101 to work, which can simultaneously control the locking and unlocking of each power switch in the power switch module.

[0104] When Linv_A, Linv_B, Linv_C, PWM_EN, PWM_DELAY, XRS_DSP, XRS_DR, and Vbus are all at high level, the second AND gate IC2 and the seventh AND gate IC7 both output high level, and the first protection module 101 and the second protection module 102 do not work.

[0105] This invention also provides a power supply, including the overcurrent protection device 10 and the power conversion device 20 as described above.

[0106] This invention, through the inclusion of a first protection module and a second protection module, reliably provides overcurrent protection signals when an overcurrent occurs in the power conversion device, thereby achieving overcurrent protection for the power conversion device. It has a wide range of applications, helps to extend the service life of devices, and ensures reliable power supply for users.

[0107] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An overcurrent protection device, characterized in that, The device is applied to a power conversion device, which includes a power switching module and a control module, wherein the power switching module is controlled by the control module; the overcurrent protection device includes a first protection module and a second protection module. The first protection module is used to generate a first blocking signal when it receives a first status signal, and send the first blocking signal to the power switch module to control the blocking of each power switch in the power switch module. The first status signal is used to characterize the input overcurrent or output overcurrent of the power conversion device. The second protection module is configured to, upon receiving the first status signal, maintain the first status signal for a first duration, generate a second blocking signal, and send the second blocking signal to the control module, so that the control module controls the blocking of each power switch in the power switch module; wherein, the first duration is not less than the signal detection period of the control module; The second protection module includes a signal transmission unit and a signal holding unit. The signal holding unit includes a first holding resistor, a second holding resistor, a delay resistor, a delay capacitor, and a delay diode. The first end of the delay resistor is connected to the second ends of both the first and second holding resistors, and the second end is connected to the second end of the delay capacitor and the signal transmission unit. The first end of the first holding resistor is connected to the first end of the second protection module, and the first ends of the second holding resistor and the delay capacitor are both connected to ground. The positive terminal of the delay diode is connected to the second end of the delay resistor, and the negative terminal is connected to the first end of the delay resistor. The delay diode is used to extend only its rising edge when the first state signal is a low-level active signal, so as to reduce the time of the falling edge of the first state signal and enable the second latching signal to reach the control module in a timely manner; or the delay diode is used to extend only its falling edge when the first state signal is a high-level active signal, so as to reduce the time of the rising edge of the first state signal and enable the second latching signal to reach the control module in a timely manner.

2. The overcurrent protection device as described in claim 1, characterized in that, The signal holding unit is configured to hold the first state signal for a first duration upon receiving the first state signal and send the first state signal to the signal transmission unit. The signal transmission unit is configured to generate a second latching signal upon receiving a first status signal from the signal holding unit, and send the second latching signal to the control module, or forward the first status signal from the signal holding unit to the control module, so that the control module controls the latching of each power switch in the power switch module.

3. The overcurrent protection device as described in claim 2, characterized in that, The signal transmission unit includes an isolation subunit; The isolation subunit is used to electrically isolate the signal between the signal holding unit and the control module.

4. The overcurrent protection device as described in claim 2, characterized in that, The signal holding unit is used to extend the rising edge or falling edge of the first state signal to hold the first state signal for a first duration.

5. The overcurrent protection device as described in any one of claims 2 to 4, characterized in that, The overcurrent protection device further includes a first detection module, wherein the first status signal is used to characterize the three-phase output overcurrent of the power conversion device; The first detection module is used to generate the first status signal when it detects an overcurrent in at least one phase output of the power conversion device, and to send the first status signal to the signal holding unit and the first protection module respectively.

6. The overcurrent protection device as described in claim 5, characterized in that, The first detection module includes a first resistor, a second resistor, a third resistor, a first AND gate, and a second AND gate; The first AND gate has its first input terminal connected to the second terminal of the first resistor, its second input terminal connected to the second terminal of the second resistor, and its output terminal connected to the first input terminal of the second AND gate; the first terminal of the first resistor is used to connect to the first phase overcurrent detection terminal of the power conversion device, and the first terminal of the second resistor is used to connect to the second phase overcurrent detection terminal of the power conversion device. The second AND gate has its second input terminal connected to the second terminal of the third resistor, and its output terminal connected to the signal holding unit and the first protection module, respectively; the first terminal of the third resistor is connected to the third phase overcurrent detection terminal of the power conversion device.

7. The overcurrent protection device as described in claim 5, characterized in that, The overcurrent protection device further includes a second detection module; the second detection module is connected between the first detection module and the first protection module, and the second detection module is also used to connect to the control module; The control module is further configured to generate a PWM lock signal when receiving the first status signal and send the PWM lock signal to the second detection module; and / or, generate a programming lock signal when detecting an external programming signal and send the programming lock signal to the second detection module; And / or, when a power supply abnormality is detected in the control module, a first power supply abnormality signal is generated and sent to the second detection module; And / or, upon detecting a power supply abnormality in either the first or second detection module, a second power supply abnormality signal is generated and sent to the second detection module; and / or, upon detecting an overvoltage on the DC bus of the power conversion device, a bus abnormality signal is generated and sent to the second detection module. The second detection module is configured to send the first status signal to the first protection module when it receives the first status signal; or, when it detects the PWM lock signal, the programming signal, the first power supply abnormality signal, the second power supply abnormality signal and / or the bus abnormality signal, generate a second status signal and send the second status signal to the first protection module. The first protection module is further configured to generate a third blocking signal when receiving the second status signal, and send the third blocking signal to the power switch module to control the blocking of each power switch in the power switch module.

8. The overcurrent protection device as described in claim 7, characterized in that, The second detection module includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a third AND gate, a fourth AND gate, a fifth AND gate, a sixth AND gate, a seventh AND gate, a first capacitor, and a second capacitor; The third AND gate has its first input terminal connected to the first detection module, its second input terminal connected to the second terminal of the fourth resistor, and its output terminal connected to the first input terminal of the fifth AND gate; the first terminal of the fourth resistor is connected to the control module. The fourth AND gate has its first input terminal connected to the second terminal of the fifth resistor, its second input terminal connected to the second terminal of the sixth resistor, and its output terminal connected to the second input terminal of the fifth AND gate; the first terminals of the fifth resistor and the sixth resistor are both connected to the control module, and the output terminal of the fifth AND gate is connected to the first input terminal of the seventh AND gate. The sixth AND gate has its first input terminal connected to the second terminal of the seventh resistor, the second terminal of the ninth resistor, and the first terminal of the first capacitor, respectively; its second input terminal connected to the second terminal of the eighth resistor, the second terminal of the tenth resistor, and the first terminal of the second capacitor, respectively; and its output terminal connected to the second input terminal of the seventh AND gate. The first terminals of the seventh resistor and the eighth resistor are both connected to the control module; the output terminal of the seventh AND gate is connected to the first protection module; the first terminals of the ninth resistor and the tenth resistor are both connected to the power supply terminal; and the second terminals of the first capacitor and the second capacitor are both connected to the ground terminal.

9. A power supply, characterized in that, It includes the overcurrent protection device and the power conversion device as described in any one of claims 1 to 8.

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