CN106532627A - Current protection circuit and system - Google Patents
Current protection circuit and system Download PDFInfo
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- CN106532627A CN106532627A CN201611143625.9A CN201611143625A CN106532627A CN 106532627 A CN106532627 A CN 106532627A CN 201611143625 A CN201611143625 A CN 201611143625A CN 106532627 A CN106532627 A CN 106532627A
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- 230000003321 amplification Effects 0.000 description 2
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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Abstract
The invention provides a current protection circuit and a current protection system comprising the same, which are used for realizing overcurrent protection of a compressor and the like so as to prevent the problem of damage to a module, a mainboard and the like caused by overlarge current. The current protection circuit includes: the circuit comprises a sampling resistor, an operational amplifier circuit, a gating circuit, a negative half-cycle protector and a positive half-cycle protector; the sampling resistor is used for sampling phase current; the operational amplifier circuit is used for amplifying the sampled current; the gating circuit is connected between the output end of the operational amplifier circuit and the input ends of the negative half-cycle protector and the positive half-cycle protector; the negative half-cycle protector is used for comparing the negative half-cycles of the amplified current so as to realize the protection of the negative half-cycles of the phase current; and the positive half-cycle protector is used for comparing the positive half-cycle of the amplified current, so that the positive half-cycle of the phase current is protected.
Description
Technical Field
The present invention relates to the field of electronic circuit technologies, and in particular, to a current protection circuit and a current protection system including the same.
Background
The compressor is used as a core device of the air conditioner, and overcurrent protection is needed in operation so as to prevent the problems of module damage, mainboard damage and the like caused by overlarge current. Although a current protection circuit exists in the prior art, in the current protection circuit, a differential amplification circuit is connected with a bus and used for collecting instantaneous current on the bus and is divided into two paths of processing, one path of current is sent to a processor through an RC (resistor-capacitor) integrating circuit, the processor collects the average current of the bus, and when the average current exceeds a set value, the load is reduced through speed reduction processing; the other path directly enters a comparator which is used for electrically comparing the comparator with the set current protection, and overcurrent interruption is generated when a protection point is exceeded. However, such a current protection circuit can only be used to protect a portion of the compressor current and does not provide complete protection.
Disclosure of Invention
In view of the above, the present invention provides a current protection circuit and a current protection system including the same, which are used to implement over-current protection for a compressor and the like, so as to prevent damage to a module, a motherboard and the like caused by an excessive current.
According to a first aspect of the present invention, there is provided a current protection circuit comprising:
the circuit comprises a sampling resistor, an operational amplifier circuit, a gating circuit, a negative half-cycle protector and a positive half-cycle protector;
the sampling resistor is used for sampling phase current;
the operational amplifier circuit is used for amplifying the sampled current;
the gating circuit is connected between the output end of the operational amplifier circuit and the input ends of the negative half-cycle protector and the positive half-cycle protector;
the negative half-cycle protector is used for comparing the negative half-cycles of the amplified current so as to realize the protection of the negative half-cycles of the phase current; and
the positive half-cycle protector is used for comparing the positive half-cycle of the amplified current, so that the positive half-cycle of the phase current is protected.
Preferably, the current protection circuit further includes:
and the biasing circuit is connected to the same-direction end of the operational amplifier circuit and is used for boosting the output of the operational amplifier circuit.
Preferably, the gating circuit comprises a positive half cycle clamping unit connected between the output of the operational amplifier circuit and the positive half cycle protector, and used for transmitting the output of the operational amplifier circuit to the positive half cycle protector so as to protect positive half cycle current.
Preferably, the positive half-cycle clamping unit is a clamping diode, the cathode of the clamping diode is connected with the output end of the operational amplifier circuit, and the anode of the clamping diode is connected with the positive half-cycle protector.
Preferably, the gate circuit further comprises a negative half-cycle clamping unit connected between the output of the operational amplifier circuit and the negative half-cycle protector, and configured to transmit the output of the operational amplifier circuit to the negative half-cycle protector, so as to protect the negative half-cycle current.
Preferably, the negative half cycle clamping unit includes a first diode, an anode of the first diode is connected to the output terminal of the operational amplifier circuit, and a cathode of the first diode is connected to the negative half cycle protector NH.
Preferably, the negative half-cycle protector comprises a first comparator, the reverse end of the first comparator is connected with the other end of the gating circuit, and the same end of the first comparator inputs a set value.
The positive half-cycle protector further comprises a fifth resistor and a sixth resistor, wherein the fifth resistor is connected between a power supply voltage (Vcc) and the reverse end of the second comparator, and the sixth resistor is connected between the reverse end of the second comparator and the ground and is used for setting an initial voltage for the reverse end of the second comparator.
Preferably, the negative half-cycle protector comprises a first comparator, the reverse end of the first comparator is connected with the cathode of the first diode, the same end inputs a set value,
preferably, the negative half-cycle protector further comprises a first resistor and a second resistor;
the first resistor is connected between the other end of the gating circuit and the reverse end, and the second resistor is connected between the reverse end and the ground.
Preferably, the positive half-cycle protector comprises a second comparator, the reverse end of the second comparator is connected with the other end of the gating circuit, and the same end of the second comparator inputs a set value.
Preferably, the bias circuit comprises a first bias resistor and a second bias resistor;
the first bias circuit is connected between the ground and the same-direction end of the operational amplifier circuit; and a second bias resistor is connected between the common terminal of the operational amplifier circuit and a supply voltage (Vcc).
Preferably, the current protection circuit is used for protection of three-phase power supply current;
the sampling resistors comprise first to third sampling resistors and are respectively used for sampling the three-phase power supply current;
the operational amplifier circuit comprises a first operational amplifier circuit, a second operational amplifier circuit, a third operational amplifier circuit and a fourth operational amplifier circuit, wherein the first operational amplifier circuit, the second operational amplifier circuit and the third operational amplifier circuit are respectively used for amplifying currents sampled by a first sampling resistor, a second sampling resistor and a third sampling resistor; and
the gating circuit comprises a first gating branch, a second gating branch, a third gating branch and a fourth gating branch, wherein the first gating branch, the second gating branch, the third gating branch and the fourth gating branch are respectively connected between the output ends of the first gating circuit, the second gating circuit, the third gating circuit and the negative half-cycle protector and the positive half-cycle protector.
Preferably, the first to third gating branches include first to third negative half-cycle clamping units and first to third positive half-cycle clamping units, respectively;
the first to third negative half-cycle clamping units are respectively connected between the first to third operational amplifier circuits and the negative half-cycle protector and are used for screening out the maximum value output by the three operational amplifier circuits;
the first to third positive half-cycle clamping units are connected between the first to third operational amplifier circuits and the positive half-cycle protector and used for screening out the minimum value output by the three operational amplifier circuits.
Preferably, the first to third negative half-cycle clamping units are first to third diodes, anodes of the first to third negative half-cycle clamping units are connected with the output end of the operational amplifier circuit, and cathodes of the first to third negative half-cycle clamping units are connected with the negative half-cycle protector;
the first to third positive half-cycle clamping units are first to third clamping diodes, the cathode of the first to third positive half-cycle clamping units is connected with the output end of the operational amplifier circuit, and the anode of the first to third positive half-cycle clamping units is connected with the negative half-cycle protector.
According to a second aspect of the present invention, there is provided a current protection system comprising:
an intelligent power module; the current protection circuit of any of the above; and a control unit;
the phase current output by the intelligent power module is processed through the current protection circuit;
and the first comparator and/or the second comparator in the current protection circuit are/is turned over to output an overcurrent protection signal to the power-only module, the intelligent power module outputs an alarm signal to the control unit, and the control unit stops outputting the driving signal.
Preferably, the control unit directly samples the output signal of the operational amplifier circuit and compares the sampled output signal with an internally stored set value to realize double protection of the current.
According to the scheme of the invention, the current protection circuit can realize the protection of the positive half cycle and the negative half cycle of the phase current, thereby providing a more reliable current protection circuit and effectively protecting a module and a mainboard of an electric appliance from being damaged due to overlarge current. Meanwhile, the current protection system has the advantage that the current protection function is more reliable due to the fact that double protection of hardware and software exists simultaneously.
The following describes the technical solution of the present invention in detail with reference to the accompanying drawings and the detailed description, and the beneficial effects of the present invention will be further clarified.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
Fig. 1 shows a block circuit diagram of a current protection circuit according to the present invention and a circuit diagram of an embodiment thereof.
Fig. 2 shows a protection circuit according to the invention applied to a three-phase power supply circuit.
Fig. 3 shows a preferred embodiment of the current protection system.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
First, a current protection circuit according to a preferred embodiment of the present invention is described with reference to fig. 1. Fig. 1 shows a block circuit diagram of a current protection circuit according to the present invention and a circuit diagram of an embodiment thereof. As shown in fig. 1, the current protection circuit includes: a sampling resistor RS1, an operational amplifier circuit OP, a gating circuit CL, a negative half-cycle protector NH and a positive half-cycle protector PH. The sampling resistor RS1 is used to sample the phase current to implement the current protection function. And the operational amplifier circuit OP is used for amplifying the sampled current. The gating circuit CL is connected between the output end of the operational amplifier circuit OP and the input ends of the negative half-cycle protector NH and the positive half-cycle protector PH and is used for inputting the output of the operational amplifier circuit into the positive half-cycle protector and the negative half-cycle protector respectively. And the negative half-cycle protector NH is used for comparing the negative half-cycle of the amplified current so as to realize overcurrent protection of the negative half-cycle of the phase current. And the positive half-cycle protector PH is used for comparing the positive half-cycle of the amplified current, so that the overcurrent protection of the positive half-cycle of the phase current is realized.
Preferably, the current protection circuit further includes a bias circuit BI connected to a common-direction terminal of the operational amplifier circuit OP for boosting an output of the operational amplifier circuit OP. Therefore, the output of the operational amplifier circuit OP is increased to a certain value, so that the sampled current signal can be completely reflected to the output voltage after being subjected to operational amplification, and more accurate detection and more reliable current protection are realized.
Through the circuit composition, the current protection circuit can realize complete positive half cycle and negative half cycle protection of the phase current, thereby providing a more reliable current protection circuit and effectively protecting a module and a mainboard of an electric appliance from being damaged due to overlarge current.
The following describes each part of the current protection circuit and its operation in detail. The sampling resistor RS1 is connected to, for example, a bus of the power supply to be protected for sampling phase currents thereon. The sampled signal is input to the inverting terminal of the operational amplifier in the operational amplifier circuit OP for amplifying the sampled current.
The gating circuit preferably includes a positive half cycle clamping unit, such as a clamping diode D4, connected between the output of the operational amplifier circuit OP and the positive half cycle protector for transmitting the output of the operational amplifier circuit to the positive half cycle protector to protect the positive half cycle current. Specifically, the cathode of the clamping diode D4 is connected to the output end of the operational amplifier circuit, and the anode is connected to the positive half-cycle protector PH. It should be noted that the positive half cycle clamping unit may also be not limited to use of a clamping diode, and may also use other circuits that can achieve the same function, such as a triode circuit.
Further preferably, the gate circuit further includes a negative half-cycle clamping unit, such as a diode D1, connected between the output of the operational amplifier circuit OP and the negative half-cycle protector, for transmitting the output of the operational amplifier circuit to the negative half-cycle protector to protect the negative half-cycle current. In one embodiment, the negative half cycle clamp unit includes a first diode D1, an anode of the first diode D1 is connected to the output of the operational amplifier circuit, and a cathode of the first diode D1 is connected to a negative half cycle protector NH. Similarly, the negative half-cycle clamping unit is not limited to the diode, and other circuits such as a triode and the like can be used to achieve the same function.
The negative half-cycle protector NH includes a first comparator comp1 having an inverting terminal connected to the other terminal of the gate CL and a common terminal to which a set value is input. When the negative half cycle of the current to be protected reaches the protection value, the output of the first comparator comp1 flips. In the side embodiment shown in fig. 1, the cathode of the first diode D1 is connected to the inverting terminal of the first comparator comp1, so that the negative half cycle of the sampled current is input to the inverting terminal of the comparator. Further, in order to facilitate hardware adjustment of the current reference value, a first resistor R4 and a second resistor R5 are provided at an inverting terminal of the first comparator comp1, the first resistor R4 is connected between the other terminal of the gate circuit and the inverting terminal, and the second resistor R5 is connected between the inverting terminal and ground. Further, a third and a fourth resistor R6, R7 are provided at the common terminal of the first comparator comp1, wherein the third resistor R6 is connected between the supply voltage Vcc voltage and the common terminal, and the fourth resistor R7 is connected between the common terminal and the ground, thereby forming a set value. When the current for the negative half cycle exceeds the protection value, the output of comparator comp1 flips.
The positive half-cycle protector PH includes a second comparator comp2 having a reverse terminal connected to the other terminal of the gating circuit CL and a common terminal to which a set value is input. When the positive half cycle of the current to be protected reaches the protection value, the output of the second comparator comp2 flips. Preferably, in order to set an initial voltage at the inverting terminal of the second comparator comp2, fifth and sixth resistors R8 and R10 are connected at the inverting terminal, wherein the fifth resistor R8 is connected between Vcc and the inverting terminal, and the sixth resistor R10 is connected between the inverting terminal and ground, so that an initial value is inputted at the inverting terminal of the second comparator comp2 by voltage division of the fifth and sixth resistors R8 and R10. And further, the setting value of the common terminal of the second comparator comp2 is divided by Vcc through seventh and eighth resistors R9 and R11, i.e., the seventh resistor R9 is connected between Vcc and the common terminal, and the eighth resistor R11 is connected between the common terminal and ground. When the positive half-cycle current does not reach the protection value, the reverse terminal voltage Ud is determined by voltage division of Vcc through R8 and R10, and Ud is higher than the reverse terminal voltage Uc. When the positive half cycle current reaches the protection value, the positive half cycle clamping unit, e.g. the clamping diode D4, is turned on, Ud is pulled low below Uc, and the output of the second comparator comp2 flips. In another preferred embodiment, the sixth resistor R10 is not provided, so that the reverse terminal voltage is equal to the output voltage of the OP-amp circuit plus the diode drop. The voltage Ud at the inverting terminal of the second comparator comp2 is higher than the set value at its forward terminal as long as the forward value of the current to be protected (positive half cycle current) does not exceed the protection value, and when the positive half cycle current reaches the protection value, Ud becomes lower and lower than Uc, the output of the second comparator comp2 flips. It should be noted that the setting of the resistors is merely exemplary, and for example, the high and low levels of the outputs of the first and second comparators can be adjusted by changing the positions of the set voltage and the output voltage of the operational amplifier circuit.
The bias circuit BI is connected to the same-direction end of the operational amplifier circuit OP, and is used for boosting the output of the operational amplifier circuit OP. In a preferred embodiment, the common terminal is biased by Vcc via a first and a second bias resistor R12 and Ra, i.e. the first bias resistor R12 is connected between ground and the common terminal, and the second bias resistor Ra is connected between the common terminal and Vcc. In another embodiment shown in fig. 1, the second bias resistor Ra is connected between the inverting terminal and an output terminal of an operational amplifier OP4, Vcc is divided by a resistor and then applied to the inverting terminal of the operational amplifier OP4 (voltage follower), and the output of the operational amplifier OP4 is divided by a resistor and then applied to the operational amplifier circuit OP, so that the voltage input to the inverting terminal of the operational amplifier circuit OP can be more stable. The output of the operational amplifier circuit is increased to a certain value, so that the sampling signal can be completely reflected to the output voltage after the operational amplifier, and the realization of the secondary half-cycle current protection function is ensured.
The operation of the current protection circuit shown in fig. 1 is described below.
First, the sampling resistor Rs1 samples the phase current to be protected, and the obtained sampling signal is input to the inverting terminal of the operational amplifier circuit OP. When the current protection circuit comprises the bias circuit BI, a dc bias is added to the non-inverting terminal of the OP-amp circuit OP from Vcc through the first and second bias resistors Ra and R12, so as to raise the output of the OP-amp circuit to a certain value, and thus the sampling signal can be completely reflected to the output voltage after passing through the OP-amp circuit.
In order to adjust the current protection value by hardware, a first resistor R4 and a second resistor R5 are provided at an inverting terminal of the first comparator comp1, and the output voltage of the operational amplifier circuit OP is divided to obtain Ua, which is input to an inverting terminal of the first comparator comp 1. On the other hand, the supply voltage Vcc is divided by the third and fourth resistors R6 and R7 to Ub, which is applied to the common terminal of the first comparator comp 1. When the current of the negative half cycle of the current reaches the protection value, the output of the first comparator comp1 flips, issuing an over-current signal (OC signal).
The positive half-cycle current protection function is realized by a positive half-cycle protector. A set value Uc is obtained by voltage division of Vcc through a fifth resistor R9 and a sixth resistor R11, when the positive half-cycle current does not reach a protection value, a reverse terminal voltage Ud is determined by voltage division of Vcc through a seventh resistor R8 and an eighth resistor R10, the Ud is higher than the Uc, when the positive half-cycle current reaches the protection value, a clamping diode D4 is conducted, the Ud is pulled down, and the output of the comp2 is inverted; or the eighth resistor R10 is not arranged, Ud is higher than Uc when the positive half-cycle current does not reach the protection value by arranging Uc, Ud becomes lower when the positive half-cycle current reaches the protection value, and Ud is lower than Uc, the output of comp2 is inverted, and an overcurrent signal (OC signal) is sent out.
The current protection circuit is applied to a single-phase power circuit as an example. The protection circuit of the invention can also be applied to a three-phase power supply circuit. Fig. 2 shows a protection circuit according to the invention applied to a three-phase power supply circuit. As shown in FIG. 2, the current protection circuit of the three-phase power supply circuit comprises first to third sampling resistors RS1-RS3 for collecting each phase current, an operational amplifier circuit OP comprising first to third operational amplifier circuits OP1-OP3 for amplifying sampled signals, a bias circuit BI consisting of first and second bias resistors R12, Ra, third and fourth bias resistors R22, Rb, and fifth and sixth bias resistors R32, Rc, respectively, a gating circuit CL consisting of negative half-cycle clamping units (first to third diodes D1-D3) and positive half-cycle clamping units (first to third clamping diodes D4-D6), and a first comparator comp1 and a second comparator comp 2. The functions of the circuits are the same as those described in the single-phase circuit, and are not described again.
In the embodiment shown in fig. 2, the negative half cycle clamping units, i.e. the first to third diodes D1, D2 and D3, are used to screen out the maximum output of three operational amplifier circuits, only one diode is turned on at the same time, the output voltage signal of the corresponding operational amplifier circuit is input to the first comparator comp1 circuit, and if the voltage signal exceeds a set value, the output of the first comparator comp1 is inverted. Similarly, the first to third clamping diodes D4, D5 and D6 are used to screen out the minimum value of the outputs of the three operational amplifier circuits, only one diode is turned on at the same time, the output voltage signal of the corresponding operational amplifier circuit is input to the second comparator comp2, and if the voltage signal is lower than the set value, the output of the second comparator comp2 is inverted.
The protection system including the current protection circuit according to the present invention is described below with reference to fig. 3. Fig. 3 shows a preferred embodiment of the protection system. As shown in fig. 3, the system includes: the intelligent power module IPM, the current protection circuit and the control unit MCU. Each phase of current output by the intelligent power module IPM is sampled by the current sampling circuit, and a sampling signal is amplified by the rear-stage operational amplifier and can be preferably added with a direct-current biased voltage signal; the gating circuit screens out the maximum value and the minimum value of the three-way operational amplifier circuit, inputs the maximum value and the minimum value into the first comparator circuit and the second comparator circuit, and compares the maximum value set by the first comparator comp1 and the minimum value set by the second comparator comp2 respectively. Whether the maximum value is exceeded or the minimum value is not exceeded, the comparator outputs an overcurrent protection signal to the IPM in a reversed mode, and the IPM sends an alarm signal such as a fault output signal (FO) to the control unit MCU after detecting the overcurrent signal (OC). After receiving the alarm signal, the MCU stops outputting the driving signal and takes necessary protective measures. Further, the MCU can also directly sample a voltage signal output by the operational amplifier circuit and compare the voltage signal with a set value stored in the software, so that double protection can be achieved, and the current protection system is safer and more reliable.
In addition, the current protection circuit and the current protection system can be used for protecting the compressor and can also be used for protecting the current of various inverter circuits.
The current protection circuit and the current protection system including the same of the present invention have been described above. According to the scheme of the invention, the current protection circuit can realize the protection of the positive half cycle and the negative half cycle of the phase current, thereby providing a more reliable current protection circuit and effectively protecting a module and a mainboard of an electric appliance from being damaged due to overlarge current. Meanwhile, the current protection system has the advantage that the current protection function is more reliable due to the fact that double protection of hardware and software exists simultaneously.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (16)
1. A current protection circuit, comprising:
the circuit comprises a sampling resistor, an operational amplifier circuit, a gating circuit, a negative half-cycle protector and a positive half-cycle protector; wherein,
the sampling resistor is used for sampling phase current;
the operational amplifier circuit is used for amplifying the sampled current;
one end of the gating circuit is connected with the output end of the operational amplifier circuit, and the other end of the gating circuit is connected with the input ends of the negative half-cycle protector and the positive half-cycle protector and is used for transmitting the output of the operational amplifier circuit to the negative half-cycle protector or the positive half-cycle protector;
the negative half-cycle protector is used for processing the negative half cycle of the amplified current so as to realize overcurrent protection of the negative half cycle of the phase current; and
the positive half-cycle protector is used for processing the positive half cycle of the amplified current, so that the overcurrent protection of the positive half cycle of the phase current is realized.
2. The current protection circuit of claim 1, further comprising:
and the bias circuit is connected to the same-direction end of the operational amplifier circuit and is used for boosting the output of the operational amplifier circuit.
3. The current protection circuit of claim 1 or 2,
the gating circuit comprises a positive half cycle clamping unit which is connected between the output end of the operational amplifier circuit and the positive half cycle protector and is used for transmitting the output of the operational amplifier circuit to the positive half cycle protector so as to protect positive half cycle current.
4. The current protection circuit of claim 3,
the positive half-cycle clamping unit is a clamping diode, the cathode of the positive half-cycle clamping unit is connected with the output end of the operational amplifier circuit, and the anode of the positive half-cycle clamping unit is connected with the positive half-cycle protector.
5. The current protection circuit of claim 1 or 2,
the gating circuit further comprises a negative half-cycle clamping unit which is connected between the output end of the operational amplifier circuit and the negative half-cycle protector and used for transmitting the output of the operational amplifier circuit to the negative half-cycle protector so as to protect the negative half-cycle current.
6. The current protection circuit of claim 5,
the negative half-cycle clamping unit is a diode, the anode of the diode is connected with the output end of the operational amplifier circuit, and the cathode of the diode is connected with the negative half-cycle protector.
7. Current protection circuit according to any of claims 1 to 6,
the negative half-cycle protector comprises a first comparator, the reverse end of the first comparator is connected with the other end of the gating circuit, and the same-direction end inputs a set value.
8. The current protection circuit of claim 7,
the negative half-cycle protector further comprises a first resistor and a second resistor;
the first resistor is connected between the other end of the gating circuit and the reverse end of the first comparator, and the second resistor is connected between the reverse end of the first comparator and the ground.
9. Current protection circuit according to any of claims 1 to 6,
the positive half-cycle protector comprises a second comparator, the reverse end of the second comparator is connected with the other end of the gating circuit, and the same-direction end inputs a set value.
10. The current protection circuit of claim 9,
the positive half-cycle protector further comprises a fifth resistor and a sixth resistor, wherein the fifth resistor is connected between a power supply voltage (Vcc) and the reverse end of the second comparator, and the sixth resistor is connected between the reverse end of the second comparator and the ground and is used for setting an initial voltage for the reverse end of the second comparator.
11. The current protection circuit of claim 2,
the bias circuit comprises a first bias resistor and a second bias resistor;
the first bias circuit is connected between the ground and the same-direction end of the operational amplifier circuit; the second bias resistor is connected between the common-direction end of the operational amplifier circuit and a power supply voltage (Vcc).
12. The current protection circuit of claim 1 or 2,
the current protection circuit is used for protecting the current of the three-phase power supply;
the sampling resistors comprise first to third sampling resistors and are respectively used for sampling the three-phase power supply current;
the operational amplifier circuit comprises a first operational amplifier circuit, a second operational amplifier circuit, a third operational amplifier circuit and a fourth operational amplifier circuit, wherein the first operational amplifier circuit, the second operational amplifier circuit and the third operational amplifier circuit are respectively used for amplifying currents sampled by a first sampling resistor, a second sampling resistor and a third sampling resistor; and
the gating circuit comprises a first gating branch, a second gating branch, a third gating branch and a fourth gating branch, wherein the first gating branch, the second gating branch, the third gating branch and the fourth gating branch are respectively connected between the output ends of the first gating circuit, the second gating circuit, the third gating circuit and the negative half-cycle protector and the positive half-cycle protector.
13. The current protection circuit of claim 12,
the first to third gating branches are respectively provided with first to third negative half-cycle clamping units and first to third positive half-cycle clamping units; wherein,
the first to third negative half-cycle clamping units are respectively connected between the output ends of the first to third operational amplifier circuits and the negative half-cycle protector and are used for screening out the maximum value output by the three operational amplifier circuits;
the first to third positive half-cycle clamping units are connected between the output ends of the first to third operational amplifier circuits and the positive half-cycle protector and used for screening out the minimum value output by the three operational amplifier circuits.
14. The current protection circuit of claim 13,
the first to third negative half-cycle clamping units are first to third diodes, anodes of the first to third diodes are connected with the output end of the operational amplifier circuit, and cathodes of the first to third diodes are connected with the negative half-cycle protector;
the first to third positive half-cycle clamping units are first to third clamping diodes, cathodes of the first to third clamping diodes are connected with an output end of the operational amplifier circuit, and anodes of the first to third clamping diodes are connected with the negative half-cycle protector.
15. A current protection system comprising a smart power module; further comprising a current protection circuit according to any of claims 1-14; and a control unit; wherein
The phase current output by the intelligent power module is processed through the current protection circuit;
when the phase current reaches a protection value, a negative half-cycle protector and/or a positive half-cycle protector in the current protection circuit outputs an overcurrent protection signal to the intelligent power module, the intelligent power module outputs an alarm signal to the control unit, and the control unit stops outputting a driving signal.
16. The current protection system of claim 15,
and the control unit samples the output signal of the operational amplifier circuit at the same time and compares the sampled output signal with a set value stored in the control unit so as to realize double protection of current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611143625.9A CN106532627A (en) | 2016-12-13 | 2016-12-13 | Current protection circuit and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611143625.9A CN106532627A (en) | 2016-12-13 | 2016-12-13 | Current protection circuit and system |
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| CN106532627A true CN106532627A (en) | 2017-03-22 |
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| CN201611143625.9A Pending CN106532627A (en) | 2016-12-13 | 2016-12-13 | Current protection circuit and system |
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|---|---|
| CN (1) | CN106532627A (en) |
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| CN108054728A (en) * | 2017-12-08 | 2018-05-18 | 珠海格力电器股份有限公司 | Current protection device, compressor circuit and current protection method thereof |
| CN109193569A (en) * | 2018-09-28 | 2019-01-11 | 珠海格力电器股份有限公司 | IPM protection device, motor and IPM protection method thereof |
| CN110412341A (en) * | 2019-08-09 | 2019-11-05 | 珠海格力电器股份有限公司 | IPM over-current detection circuit |
| CN110460018A (en) * | 2019-08-29 | 2019-11-15 | 合肥阳光电动力科技有限公司 | A kind of electric machine controller and its alternate protection circuit |
| CN110707664A (en) * | 2019-10-30 | 2020-01-17 | 珠海格力电器股份有限公司 | IPM protection detection circuit |
| CN114963346A (en) * | 2022-05-06 | 2022-08-30 | 宁波奥克斯电气股份有限公司 | Totem-pole circuit, air conditioner external unit and air conditioner |
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| CN114963346A (en) * | 2022-05-06 | 2022-08-30 | 宁波奥克斯电气股份有限公司 | Totem-pole circuit, air conditioner external unit and air conditioner |
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Application publication date: 20170322 |