The present disclosure claims priority to Chinese Patent Application No. 202011289085.1, filed on Nov. 17, 2020, and entitled ‘current detection circuit, current leakage detection method, and charging system’, which is hereby incorporated by reference in its entirely.
The present disclosure relates to a technical field of new energy, and particularly to a current detection circuit, current leakage detection method, and charging system.
With the rapid development of the field of electric vehicles, people pay more and more attention to the safety of charging products of electric vehicles, in which the detection of leakage current in a charging process is an important requirement. By the detection of leakage current, it is possible to determine whether there is leakage current in a charging process of an electric vehicle by a charging pile, and cut off the connection between the charging pile and the electric vehicle in time when there is leakage current, so as to avoid causing greater hazards to the electric vehicle, the charging pile, and surrounding devices or people, and improve the safety of the charging process.
Therefore, how to detect the leakage current in the charging process is a technical problem urgently to be solved by those skilled in the art.
The embodiments of the present disclosure provide a current detection circuit, a current leakage detection method and a charging system, which are adopted to detect leakage current in a charging process.
In a first aspect, an embodiment of the present disclosure provides a current detection circuit, including an excitation module and a comparison module. The excitation module is connected to a first winding wound in a magnetic induction coil. A lead passes through the magnetic induction coil. The excitation module is configured to output an excitation signal to the first winding. The comparison module is configured to determine whether there is leakage current in the lead based on the feedback signal induced by the first winding and a preset reference signal.
In a second aspect, an embodiment of the present disclosure provides a charging system, including a charging device, a magnetic induction coil, a control circuit, and a current detection circuit. The current detection circuit is the aforementioned current detection circuit according to the embodiment of the present disclosure. The current detection circuit is connected to the magnetic induction coil and the control circuit, respectively. The control circuit is connected to the charging device through a first lead which passes through the magnetic induction coil. The current detection circuit is configured to output an indication signal when it is determined that there is leakage current in the first lead. The control circuit is configured to control the charging device to stop supplying electric energy to the outside upon receipt of the indication signal; and control the charging device to supply electric energy to the outside upon no receipt of the indication signal.
In this way, the control circuit can control whether the charging device should supply electric energy to the outside according to the fact whether the current detection circuit outputs the indication signal, so that when there is leakage current in the first lead passing through the magnetic induction coil, i.e., when there is an electric leakage as the charging device supplies electric energy to the outside, a loop of the charging device for supplying electric energy to the outside is cut off in time, so that the charging device stops supplying electric energy to the outside, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process.
In a third aspect, an embodiment of the present disclosure provides a current leakage detection method, including:
According to the current detection circuit, the current leakage detection method and the charging system provided by the embodiments of the present disclosure, by providing the current detection circuit, it is possible to output an excitation signal to the first winding in the magnetic induction coil, and then determine whether there is leakage current in a first lead passing through the magnetic induction coil based on a feedback signal induced by the first winding and a reference signal, thereby determining whether there is an electric leakage while a charging device supplies electric energy to the outside, and providing a determination result to a control circuit. When there is an electric leakage, the control circuit can cut off a loop of the charging device for supplying electric energy to the outside in time, so that the charging device can stop supplying electric energy to the outside, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process. Meanwhile, the reaction speed for controlling the charging process can be increased to improve the timeliness. In addition, the application range of the current detection circuit is greatly widened because it is not limited by geography or climate.
Specific implementations of a current detection circuit, a current leakage detection method, and a charging system according to the embodiments of the present disclosure will be described in detail below with reference to the drawings. It should be noted that the described embodiments are only a part, rather than all, of the embodiments of the present disclosure. All other embodiments derived by persons skilled in the art from the embodiments of the present disclosure without making inventive efforts shall fall within the scope of the present disclosure.
An embodiment of the present disclosure provides a current detection circuit. As illustrated in
The excitation module 21 is configured to output an excitation signal to the first winding u1 and receive a feedback signal induced by the first winding u1.
The comparison module 22 is configured to determine whether there is leakage current in the lead L0 based on the feedback signal induced by the first winding u1 and a preset reference signal.
In this way, by providing the current detection circuit, it is possible to output an excitation signal to the first winding in the magnetic induction coil, and then determine whether there is leakage current in the lead passing through the magnetic induction coil based on the feedback signal induced by the first winding and the reference signal, which is beneficial for the outside world to respond in time and effectively based on the determination result, thereby reducing the occurrence of hazards, and improving the safety and reliability of the charging process. Meanwhile, the reaction speed for controlling the charging process can be increased to improve the timeliness. In addition, the application range of the current detection circuit is greatly widened because it is not limited by geography or climate.
It should be noted that, optionally, the detected leakage current may be AC current or DC current That is, the current detection circuit according to the embodiment of the present disclosure can detect both AC leakage current and DC leakage current. Especially when the DC leakage current is detected, the minimum detectable DC leakage current may be 0.01 mA, and the detection precision may be ±0.01%. The current detection circuit according to the embodiment of the present disclosure has an extensive application range and meets the needs of different application scenarios, thereby greatly improving the practicability of the current detection circuit. Meanwhile, the detection is faster and more accurate, which greatly improves the detection sensitivity.
Specifically, regardless of whether the DC leakage current or the AC leakage current is detected, the specific detection principle in the detection process may include: when the excitation signal is output to the first winding, under the action of the electromagnetic induction, the excitation signal enables the magnetic induction coil to generate a magnetic field; when there is leakage current in the lead, the magnetic field generated by the excitation signal may be changed, which causes induced electromotive forces at two ends of the first winding, and then induced current can be generated when the two ends of the first winding form a loop.
The lead may include a neutral line and a live line. If there is a difference between the current output from the live line and the current input from the neutral line, it can be considered that there is leakage current in the lead.
At this time, there is induced current (i.e., a feedback signal) in the excitation module connected to the first winding, and it can be determined whether there is leakage current in the lead based on a relationship between the feedback signal and the reference signal.
Therefore, regardless of whether the DC leakage current or the AC leakage current is detected, the reference signals used in the detection process may be the same, and the excitation signals used in the detection process may be the same. Of course, the reference signal and the excitation signal can be adjusted and changed according to the type of the leakage current, as long as the leakage current can be detected. The specific implementation forms of the reference signal and the excitation signal can be set according to actual needs, which is not limited here.
In addition, regardless of whether the DC leakage current or the AC leakage current is detected, the waveform of the feedback signal is determined by the type of the leakage current in the lead, so the implementation form of the feedback signal corresponds to the type of the leakage current in the lead.
Moreover, the excitation signal may have adjustable frequency and amplitude which are determined depending on factors such as the specific structure of the current detection circuit, the detection precision, etc., which is not limited here.
Furthermore, the waveform of the excitation signal may be, but not limited to, a square wave, or other waveforms, such as a cosine wave, which can be set according to actual needs and is not limited here.
Optionally, in the embodiment of the present disclosure, the comparison module is specifically configured to:
The feedback signal may be a positive voltage or a negative voltage, and correspondingly, the reference voltage may be set as a positive voltage, so that the absolute value of the feedback signal can be compared with the reference voltage.
In this way, by comparing the the feedback signal with the reference signal, it is possible to quickly and effectively determine whether there is leakage current in the lead, thereby improving the detection efficiency of the leakage current.
Optionally, in the embodiment of the present disclosure, as illustrated in
The comparison unit 22a is configured to: determine an effective signal and an interference signal in the feedback signal (denoted by Sk), and amplify the effective signal to obtain a first signal (denoted by Z1); determine whether there is leakage current in the lead based on the first signal Z1 and the reference signal; and output a second signal Z2 if it is determined that there is leakage current in the lead.
In this way, by providing the comparison unit, the function of the comparison module can be realized, thereby detecting the leakage current in the lead. Meanwhile, it is possible to improve the detection precision of the leakage current and the accuracy of the detection result, thus providing accurate and effective reference for subsequent processing.
Optionally, in the embodiment of the present disclosure, as illustrated in
The first operational amplifier unit 22b is configured to perform signal amplification processing on the feedback signal Sk before the effective signal and the interference signal in the feedback signal Sk are determined.
In this way, it is possible to effectively extract the effective signal and eliminate the interference signal, so that the comparison unit can accurately and effectively determine whether there is leakage current in the lead, and the accuracy of the determination result can be improved.
Optionally, in the embodiment of the present disclosure, as illustrated in
In this way, by performing the amplification processing on the second signal, which can also be understood as power-level amplification processing, it is beneficial for the external device to identify the second signal upon receipt of it, thereby promoting the timely and effective processing and response by the external device, and improving the safety and reliability of the charging process.
Specifically, in the embodiment of the present disclosure, as illustrated in
The first operational amplifier unit 22b may include a first operational amplifier Y1, a first resistor R1, a second resistor R2, and a tenth resistor R10.
The second operational amplifier unit 22c may include a third operational amplifier Y3, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth capacitor C6.
The first operational amplifier Y1 has a first input end connected to a first end of the first resistor R1 and the excitation module 21, respectively. The first operational amplifier Y1 has a second input end connected to a first end of the second resistor R2, and the excitation module 21, respectively. The first operational amplifier Y1 has a third input end connected to a power signal terminal VCC, and a fourth input end connected to a ground terminal GND. The first operational amplifier Y1 has an output end electrically connected to a second end of the first resistor R1, and a first end of the tenth resistor R10, respectively.
The second operational amplifier Y2 has a first input end connected to a first end of the third capacitor C3, and a first end of the ninth resistor R9, respectively. The second operational amplifier Y2 has a second input end connected to a first end of the fourth capacitor C4, and a first end of the fifth capacitor C5, respectively. The second operational amplifier Y2 has a third input end connected to the power signal terminal VCC, and a fourth input end connected to the ground terminal GND. The second operational amplifier Y2 has an output end connected to a first end of the eighth resistor R8, a second end of the third capacitor C3, a first end of the sixth resistor R6, and a first end of the seventh resistor R7, respectively;
The third operational amplifier Y3 has a first input terminal connected to a first end of the first capacitor C1, a first end of the second capacitor C2, a second end of the fourth capacitor C4, and a second end of the fifth capacitor C5, respectively. The third operational amplifier Y3 has a second input end connected to a first end of the third resistor R3, a first end of the fourth resistor R4, and a first end of the sixth capacitor C6, respectively. The third operational amplifier Y3 has a third input terminal connected to the power signal terminal VCC, and a fourth input terminal connected to the ground terminal GND. The third operational amplifier Y3 has an output end connected to an output end of the current detection circuit, a second end of the sixth resistor C6, and a first end of the fifth resistor R5, respectively.
The first comparator B1 has a first input terminal connected to a reference voltage terminal S0 used to provide a reference signal, and a second input end connected to an output end of the first comparator B1, a second end of the second resistor R2, and a first end of the first capacitor C1, respectively. The first comparator B1 has a third input end connected to the power signal terminal VCC, and a fourth input end connected to the ground terminal GND.
A second end of the third resistor R3, a second end of the fourth resistor R4, a second end of the fifth resistor R5, a second end of the sixth resistor R6, and a second end of the seventh resistor R7 are all connected to a second end of the first capacitor C1.
A second end of the eighth resistor R8 and a second end of the ninth resistor R9 are both connected to a second end of the tenth resistor R10.
In this way, through the cooperative use of the first operational amplifier, the first resistor, the second resistor and the tenth resistor, it is possible to realize the function of the first operational amplifier unit to implement the first-stage amplification processing on the feedback signal. In addition, through the cooperative use of the sixth resistor, the seventh resistor, the eighth resistor, the ninth resistor, the first capacitor, the second capacitor, the third capacitor, the fourth capacitor and the fifth capacitor, it is possible to filter out the interference signal in the first signal and remain the effective signal, so as to facilitate the second operational amplifier to perform the second-stage amplification processing on the effective signal. In addition, through the cooperative use of the third operational amplifier, the third resistor, the fourth resistor, the fifth resistor and the sixth capacitor, it is possible to perform the three-stage amplification processing on a third signal, thereby achieving a power-level signal amplification.
Optionally, in the embodiment of the present disclosure, the comparison module further includes a seventh capacitor disposed between the power signal terminal and the ground terminal.
In
It should be noted that, optionally, in the embodiment of the present disclosure, the specific structure of the comparison module is not limited to that illustrated in
Optionally, in the embodiment of the present disclosure, as illustrated in
The specific structure of the reference voltage generator 23 may be as illustrated in
Of course, the specific structure of the reference voltage generator may also be any other structure capable of generating a reference voltage well known to those skilled in the art, and may be set and selected according to actual needs, which is not limited here.
In this way, by providing the reference voltage generator, it is possible to provide a reference voltage with high precision and consistency for the comparison unit, thereby improving the accuracy of the detection result of the leakage current. Meanwhile, the reference voltage can be generated by the reference voltage generator itself without an external application or input, thereby reducing the dependence on the external signal.
Optionally, in the embodiment of the present disclosure, as illustrated in
In this way, by providing the signal generator, it is possible to effectively realize the function of the excitation module, thereby detecting the leakage current in the lead.
Specifically, in the embodiment of the present disclosure, as illustrated in
In this way, through the voltage division processing on the excitation signal, it is possible to effectively transmit the processed excitation signal to the two ends of the first winding, thereby facilitating the subsequent detection of the leakage current in the lead.
Optionally, in the embodiment of the present disclosure, as illustrated in
The voltage dividing unit 21b includes a twelfth resistor R12, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a twentieth resistor R20 and a twenty-first resistor R21.
The second comparator B2 has a first input end connected to a first input end of the third comparator B3, a first end of the nineteenth resistor R19, and a first end of the seventeenth resistor R17, respectively. The second comparator B2 has a second input end connected to a second input end of the third comparator B3, a first end of the thirteenth resistor R13, and a first end of the twelfth resistor R12, respectively. The second comparator B2 has a third input end connected to a power signal terminal VCC for providing a power signal, a fourth input end connected to a ground terminal GND, and an output end connected to a first pin of a driver Q1 and a first end of the eleventh resistor R11, respectively.
The third comparator B3 has a third input end connected to the power signal terminal VCC, a fourth input end connected to the ground terminal GND, and an output end connected to a second pin of the driver Q1 and a first end of the fourteenth resistor R14, respectively;
The driver Q1 has a third pin connected to the power signal terminal VCC, a fourth pin connected to the ground terminal GND, and a fifth pin connected to a first end d1 of the first winding u1 and a first end of the eighteenth resistor R18, respectively. The driver Q1 has a sixth pin connected to a first end of the sixteenth resistor R16, a first end of the twentieth resistor R20, and a first end of the twenty-first resistor R21, respectively;
A second end of the thirteenth resistor R13 and a second end of the nineteenth resistor R19 are both connected to the ground terminal GND.
A second end of the eleventh resistor R11 and a second end of the fourteenth resistor R14 are both connected to the power signal terminal VCC.
A second end of the twelfth resistor R12 is connected to a second end of the sixteenth resistor R16, a first end of the fifteenth resistor R15, and a second end d2 of the first winding u1, respectively.
A second end of the fifteenth resistor R15 is connected to the comparison module 21.
A second end of the eighteenth resistor R18 is connected to a second end of the twenty-first resistor R21 and a second end of the seventeenth resistor R17, respectively.
A second end of the twentieth resistor R20 is connected to the comparison module 21.
In this way, through the cooperative work of the above structures, it is possible to generate the excitation signal, and perform the voltage division processing on the excitation signal, thereby achieving the excitation of the magnetic induction coil and promoting the detection of the leakage current.
Optionally, in the embodiment of the present disclosure, as illustrated in
An anode of the first diode D1 and a cathode of the second diode d2 are both connected to the second end d2 of the first winding u1. A cathode of the first diode D1 is connected to the power signal terminal VCC. An anode of the second diode D2 is connected to the ground terminal GND.
An anode of the third diode D3 and a cathode of the fourth diode D4 are both connected to the first end d1 of the first winding u1. A cathode of the third diode D3 is connected to the power signal terminal VCC. An anode of the fourth diode D4 is connected to the ground terminal GND.
In this way, by providing a plurality of diodes, it is possible to protect the signal processing unit due to the unidirectional conduction function of the diodes, thereby ensuring that the signal processing unit can transmit signals normally and effectively.
Optionally, in the embodiment of the present disclosure, the excitation module further includes an eighth capacitor to an eleventh capacitor.
The eighth capacitor and the ninth capacitor are connected in parallel between a third pin of the driver and a fourth pin of the driver.
A first end of the tenth capacitor and a first end of the eleventh capacitor are connected to a third input end of the second comparator and a fourth input end of the second comparator, respectively. A second end of the tenth capacitor and a second end of the eleventh capacitor are connected to a third input end of the third comparator and a fourth input end of the third comparator, respectively.
In
It should be noted that, optionally, in the embodiment of the present disclosure, the specific structure of the excitation module is not limited to that illustrated in
Optionally, in the embodiment of the present disclosure, as illustrated in
The auxiliary module 24 is connected to the second winding u2 wound in the magnetic induction coil L0. The auxiliary module 24 is configured to output a preset current signal to the second winding u2 in an initialization stage where no current passes through the lead L0, so as to determine whether the excitation module 21 and the comparison module 22 can work normally.
It should be noted that the first winding and the second winding wound in the magnetic induction coil are two different windings. When there is no current passing through the lead, a current signal may be input into the second winding to simulate the situation that there is leakage current in the lead passing through the magnetic induction coil. When the excitation module inputs the excitation signal into the first winding, the magnetic field generated by the excitation signal will be changed because of the current in the second winding. If it is determined, through the excitation module and the comparison module, that the feedback signal induced by the first winding is greater than the reference signal, it may be determined that the excitation module and the comparison module can work normally and effectively, thereby achieving the self-check of the current detection circuit.
Optionally, in the embodiment of the present disclosure, the auxiliary module 24 includes a current generator.
In this way, it is possible to realize the function of the auxiliary module through a simple structure, thereby achieving the self-check of the current detection circuit.
The structure of the current generator in the auxiliary module 24 is illustrated in
Of course, the specific structure of the current generator may also be any other structure capable of generating current well known to those skilled in the art, and may be set and selected according to actual needs, which is not limited here.
The working process of the current detection circuit according to the embodiment of the present disclosure will be described with reference to the structural diagram illustrated in
The second comparator B2 and the third comparator B3 work under the cooperation of the thirteenth resistor R13 and the nineteenth resistor R19, and the generated signals are input to the first pin and the second pin of the driver Q1, respectively. Through the pull-up of the eleventh resistor R11 disposed at the first pin of the driver Q1 and the fourteenth resistor R14 disposed at the second pin of the driver Q1, the output capability of the driver Q1 can be improved, so that the excitation signal, whose frequency and amplitude can be adjusted according to actual needs, output by the driver Q1 through the fifth pin and the sixth pin are more accurate and effective:
It should be emphasized that since the current detection circuit according to the embodiment of the present disclosure is composed of simple components, it is beneficial to reduce the manufacturing cost of the current detection circuit. Meanwhile, the overall occupied area of the current detection circuit is small, so that the overall size of the current detection circuit is small, which is convenient for installation and use in various charging systems and greatly improves the practicability of the current detection circuit.
In addition, according to the waveform of the current signal, the types of the leakage current at present mainly include a sinusoidal current signal, a current signal containing a pulsating DC component and a current signal containing a smooth DC component. The current detection circuit according to the embodiment of the present disclosure can detect the above three types of leakage current and is not limited by the type of the leakage current to be detected during actual use. Therefore, the current detection circuit according to the embodiment of the present disclosure has a wide application range.
Based on the same inventive concept, an embodiment of the present disclosure provides a charging system as illustrated in
The current detection circuit 20 is the aforementioned current detection circuit according to the embodiment of the present disclosure, and the current detection circuit 20 is connected to the magnetic induction coil 10 and the control circuit 103, respectively. The control circuit 103 is connected to the charging device 101 through a first lead 104 which passes through the magnetic induction coil 10.
The current detection circuit 20 is configured to output an indication signal K0 when it is determined that there is leakage current in the first lead 104.
The control circuit is configured to control the charging device 101 to stop supplying electric energy to the outside upon receipt of the indication signal K0, or control the charging device 101 to supply electric energy to the outside upon no receipt of the indication signal K0.
In this way, the control circuit can control whether the charging device should supply electric energy to the outside according to the fact whether the current detection circuit outputs the indication signal. Therefore, when there is leakage current in the first lead passing through the magnetic induction coil, i.e., when there is an electric leakage as the charging device supplies electric energy to the outside, a loop of the charging device for supplying electric energy to the outside is cut off in time, so that the charging device stops supplying electric energy to the outside, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process.
In addition, when the control circuit cuts off the loop of the charging device for supplying electric energy to the outside, with a response speed at a millisecond-level and at the earliest within 0.01 ms, thereby greatly improving the control of the charging system and the safety and reliability of the charging process.
Optionally, in an embodiment of the present disclosure, as illustrated in
Specifically, in an embodiment of the present disclosure, as illustrated in
Optionally, in an embodiment of the present disclosure, as illustrated in
That is, the switch, rather than the controller, is disposed on the neutral line and the live line.
The controller may control the switch to be switched off when receiving the indication signal, so as to cut off the connection between the charging device and the charged device and stop the charging process; or, the controller may control the switch to be switched on when not receiving the indication signal, so as to keep the connection between the charging device and the charged device and maintain the normal charging process.
In addition, the charging system may be provided with at least one switch. When there is one switch, it may be disposed on the neutral line or the live line. Alternatively, when there are two switches, one of which may be disposed on the neutral line and the other of which may be disposed on the live line.
Specifically, in an embodiment of the present disclosure, the switch may be, but not limited to, a relay, and may be any other structure capable of realizing the switch function well known to those skilled in the art, which is not limited here.
Optionally, in an embodiment of the present disclosure, the connection mode between the first winding and the current detection circuit may include:
One of the modes 1 and 2 may be selected to realize the connection between the first winding and the current detection circuit depending on the actual situation, so as to meet the needs of different application scenarios and improve the design flexibility.
Based on the same inventive concept, an embodiment of the present disclosure provides a current leakage detection method, the implementation principle of which is similar to that of the aforementioned current detection circuit, and the specific implementation of the current detection circuit as described above may be referred to for the implementation of the detection method, and the repetitive description is omitted herein.
Specifically, as illustrated in
In this way, it is possible to output an excitation signal to the first winding in the magnetic induction coil, and then determine whether there is leakage current in the lead passing through the magnetic induction coil based on the feedback signal induced by the first winding and the reference signal, thereby responding to the electric leakage in time and effectively based on the determination result, reducing the occurrence of hazards, and improving the safety and reliability of the charging process. Meanwhile, the reaction speed for controlling the charging process can be increased to improve the timeliness. In addition, the application range of the current detection circuit is greatly widened because it is not limited by geography or climate.
Optionally, in an embodiment of the present disclosure, determining whether there is leakage current in the lead passing through the magnetic induction coil based on the feedback signal and the preset reference signal includes:
Obviously, those skilled in the art can make various modifications and variations to the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, it is intended that the present disclosure encompass these modifications and variations provided that they are within the scope of the claims and the equivalents thereof.
Number | Date | Country | Kind |
---|---|---|---|
202011289085.1 | Nov 2020 | CN | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/CN2021/129979 | 11/11/2021 | WO |