Current detection device and servo driver equipment

Abstract

The utility model discloses a current detection device and servo driver equipment. The current detection device comprises an electromagnetic anti-interference circuit, a rectifier bridge, a three-phase inverter bridge, a bus capacitor, an electric leakage detection circuit and a control module. By arranging the electric leakage detection circuit between the rectifier bridge and the electromagnetic anti-interference circuit or between the three-phase inverter bridge and the rectifier bridge, the electric leakage detection circuit can quickly detect and judge the current generation condition of the rectifier bridge, the bus capacitor, the three-phase inverter bridge or the motor relative to the ground wire leakage. Therefore, the safety of equipment and personnel is protected.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and particularly to a current detection device and a servo drive device. Background Art

[0002] Servo drives and frequency converters usually drive motors through direct mains input. After the mains power is rectified and filtered, it is output by a three-phase inverter bridge to drive the motor to move. Among them, the line length from the three-phase inverter bridge to the motor is usually between several meters and dozens of meters. However, once the line is damaged, it may cause electric shock accidents or damage to the enameled wire of the motor winding, and even short-circuit of the motor magnet. Minor damage may cause equipment damage, but serious damage may pose a threat to personal safety.

[0003] To solve this problem, the most common method currently is to set up a detection circuit on both the high-side and low-side between the bus capacitor and the three-phase inverter bridge. When a short circuit occurs between the output power lines of the three-phase inverter bridge or the output power line is short-circuited to the ground, the corresponding detection circuit will detect the existence of the short circuit.

[0004] When the existing detection circuit detects the situation of short circuit to the ground, there is a problem that the short-circuit current to the ground is too small to reach the trigger threshold of the detection circuit, so that the protection cannot be triggered in time, resulting in damage to the motor equipment or electric shock to personnel. Summary of the Utility Model

[0005] The main technical problem to be solved by this application is to provide a current detection device and a servo drive device, which can quickly and sensitively detect and judge under the condition of short circuit to the ground, and timely protect the safety of equipment and personnel.

[0006] To solve the above technical problem, the first technical solution adopted by this application is to provide a current detection device, including: an electromagnetic anti-interference circuit, and the input end of the electromagnetic anti-interference circuit receives the mains current;

[0007] A rectifier bridge, the first input end of the rectifier bridge is connected to the first output end of the electromagnetic anti-interference circuit, and the second input end of the rectifier bridge is connected to the second output end of the electromagnetic anti-interference circuit;

[0008] A three-phase inverter bridge, the first input end of the three-phase inverter bridge is connected to the first output end of the rectifier bridge, the second input end of the three-phase inverter bridge is connected to the second output end of the rectifier bridge, and the output end of the three-phase inverter bridge is connected to the motor;

[0009] A bus capacitor, where the positive electrode of the bus capacitor is connected between the first input end of the three-phase inverter bridge and the first output end of the rectifier bridge, and the negative electrode of the bus capacitor is connected between the second input end of the three-phase inverter bridge and the second output end of the rectifier bridge;

[0010] A leakage detection circuit, arranged between the rectifier bridge and the electromagnetic anti-interference circuit, or between the three-phase inverter bridge and the rectifier bridge, for obtaining a detection voltage;

[0011] A control module, respectively connected to the leakage detection circuit and the three-phase inverter bridge, for controlling the three-phase inverter bridge to stop working and generating a first alarm signal when the detection voltage exceeds a preset voltage threshold.

[0012] In some embodiments, the leakage detection circuit includes a zero-sequence current transformer, a first sampling resistor, and a first sampling circuit. One end of the zero-sequence current transformer is respectively connected to one end of the first sampling resistor and one end of the first sampling circuit, and the other end of the zero-sequence current transformer is respectively connected to the other end of the first sampling resistor and the other end of the first sampling circuit. The control module is connected to the first sampling circuit.

[0013] In some embodiments, the current detection device further includes a ground wire. The zero-sequence current transformer is used to generate a current when the rectifier bridge, or the bus capacitor, or the three-phase inverter bridge, or the motor leaks electricity relative to the ground wire. The induction winding of the zero-sequence current transformer generates an induction current, and the induction current flows through the first sampling resistor to generate a voltage. The first sampling circuit is used to collect the voltage to obtain the detection voltage.

[0014] In some embodiments, the leakage detection circuit is arranged between the first input end of the rectifier bridge and the first output end of the electromagnetic anti-interference circuit and between the second input end of the rectifier bridge and the second output end of the electromagnetic anti-interference circuit. The connection line between the first input end of the rectifier bridge and the first output end of the electromagnetic anti-interference circuit and the connection line between the second input end of the rectifier bridge and the second output end of the electromagnetic anti-interference circuit pass through the zero-sequence current transformer.

[0015] In some embodiments, the leakage detection circuit is arranged between the first input end of the three-phase inverter bridge and the first output end of the rectifier bridge and between the second input end of the three-phase inverter bridge and the second output end of the rectifier bridge. The connection line between the first output end of the rectifier bridge and the positive electrode of the bus capacitor and the connection line between the second output end of the rectifier bridge and the negative electrode of the bus capacitor pass through the zero-sequence current transformer.

[0016] In some embodiments, the leakage detection circuit is disposed between the first input end of the three-phase inverter bridge and the first output end of the rectifier bridge, and between the second input end of the three-phase inverter bridge and the second output end of the rectifier bridge. The connection line between the positive electrode of the bus capacitor and the first input end of the three-phase inverter bridge, and the connection line between the negative electrode of the bus capacitor and the second input end of the three-phase inverter bridge pass through the zero-sequence current transformer.

[0017] In some embodiments, the current detection device further includes an overcurrent detection circuit, which is disposed between the negative electrode of the bus capacitor and the second input end of the three-phase inverter bridge.

[0018] In some embodiments, the overcurrent detection circuit includes a second sampling resistor and a second sampling circuit. One end of the second sampling resistor is connected to the negative electrode of the bus capacitor, the other end of the second sampling resistor is connected to the second input end of the three-phase inverter bridge, and the second sampling circuit is respectively connected to both ends of the second sampling resistor.

[0019] In some embodiments, the control module is connected to the second sampling circuit, and is configured to control the three-phase inverter bridge to stop working and generate a second alarm signal when the detected current of the second sampling circuit is greater than a preset current threshold.

[0020] Another technical solution adopted in this application is to provide a servo driver device, and the servo driver device includes the current detection device of the first technical solution.

[0021] The beneficial effect of this application is that by arranging a leakage detection circuit between the rectifier bridge and the electromagnetic anti-interference circuit, or between the three-phase inverter bridge and the rectifier bridge, the leakage detection circuit can quickly detect and judge the current generated by the rectifier bridge, the bus capacitor, the three-phase inverter bridge or the motor leaking electricity to the ground wire, so as to protect the safety of the equipment and personnel. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0023] Figure 1 is a circuit architecture example diagram of a current detection device provided by this application;

[0024] Figure 2 is another circuit architecture example diagram of a current detection device provided by this application;

[0025] Figure 3 This is a schematic diagram of the circuit architecture of another current detection device provided by this application. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. It can be understood that the specific embodiments described herein are only used to explain this application, rather than limiting this application. Additionally, it should be noted that for the convenience of description, only parts related to this application rather than all structures are shown in the accompanying drawings. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by this application.

[0027] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0028] The currently common overcurrent detection method is to add an overcurrent detection circuit on each of the high-side and low-side between the bus capacitor and the three-phase inverter bridge. When a short circuit occurs at the output end of the three-phase inverter bridge and a large current flows through the sampling resistor, after the corresponding detection circuit detects the short-circuit large current, the three-phase inverter bridge is controlled to stop working, thereby truncating the short-circuit loop and protecting the motor equipment or personal safety. Both overcurrent detection circuits are connected with the sampling resistor and the detection circuit.

[0029] Among them, when setting the protection threshold, the overcurrent detection circuit needs to consider the current during normal operation. Therefore, the protection threshold will be set relatively high, at least 1.1 times the normal operating current. For example, for a 750W servo driver, the protection threshold is generally set above 15A.

[0030] When a ground short circuit occurs, a relatively large current value is required to trigger the protection. After the protection is triggered, the motor equipment has been damaged, or the current protection threshold cannot be reached to trigger the protection, resulting in a situation of electric shock to personnel. In addition, for the two overcurrent detection circuits, in the case of short circuit of the three-phase inverter bridge arm or short circuit protection between the phases of the three-phase inverter bridge output, the functions overlap, causing waste of resources.

[0031] Please refer to Figure 1 as shown Figure 1 This is a schematic diagram of the circuit architecture of a current detection device provided by this application. The current detection device 10 of this application includes an electromagnetic anti-interference circuit 11, a rectifier bridge 12, a three-phase inverter bridge 13, a bus capacitor 14, a leakage detection circuit 15, and a control module 16.

[0032] Among them, the input end of the electromagnetic anti-interference circuit 11 receives the mains current, that is, the input end of the electromagnetic anti-interference circuit 11 is connected to the mains. Electromagnetic interference (EMI) is the electronic noise that interferes with cable signals and reduces signal integrity, usually generated by electromagnetic radiation sources such as motors and machines. In actual electronic devices, EMI mainly propagates through the wires in the circuit. When the current in the wire changes, an electromagnetic field will be generated, thus interfering with the outside world.

[0033] Generally, electromagnetic interference is suppressed by means such as shielding, grounding (floating ground, single-point grounding, and grounding grid), and filtering. The electromagnetic anti-interference circuit 11 of this embodiment can be a filtering circuit, which is used to filter the noise of the input and output of the mains current and eliminate its conducted interference. It should be noted that this embodiment does not limit the specific circuit design.

[0034] The first input end 121 of the rectifier bridge 12 is connected to the first output end 111 of the electromagnetic anti-interference circuit 11, and the second input end 122 of the rectifier bridge 12 is connected to the second output end 112 of the electromagnetic anti-interference circuit 11.

[0035] The main function of the rectifier bridge 12 is to convert alternating current into direct current. Generally, the rectifier bridge 12 can be applied in electronic devices such as power supplies, power adapters, motor controllers, and battery chargers.

[0036] In this embodiment, the rectifier bridge 12 converts the alternating current output by the electromagnetic anti-interference circuit 11, that is, the first input end 121 and the second input end 122 of the rectifier bridge 12 respectively receive the alternating current output by the first output end 111 and the second output end 112 of the electromagnetic anti-interference circuit 11.

[0037] The first input end 131 of the three-phase inverter bridge 13 is connected to the first output end 123 of the rectifier bridge 12, the second input end 132 of the three-phase inverter bridge 13 is connected to the second output end 124 of the rectifier bridge 12, and the output end of the three-phase inverter bridge 13 is connected to the motor 17. Among them, the three-phase inverter bridge 13 is a power conversion device for converting direct current electrical energy into alternating current electrical energy.

[0038] Among them, the first input end 131 of the three-phase inverter bridge 13 refers to the positive input end of the three-phase inverter bridge 13, and the first output end 123 of the rectifier bridge 12 refers to the positive output end of the rectifier bridge 12. The connection between the first input end 131 of the three-phase inverter bridge 13 and the first output end 123 of the rectifier bridge 12, that is, the connection between the positive input end of the three-phase inverter bridge 13 and the positive output end of the rectifier bridge 12, is usually referred to as the high-side connection.

[0039] The second input terminal 132 of the three-phase inverter bridge 13 refers to the negative input terminal of the three-phase inverter bridge 13, and the second output terminal 124 of the rectifier bridge 12 refers to the negative output terminal of the rectifier bridge 12. The second input terminal 132 of the three-phase inverter bridge 13 is connected to the second output terminal 124 of the rectifier bridge 12 to form a low-side connection.

[0040] The positive pole of the bus capacitor 14 is connected between the first input terminal 131 of the three-phase inverter bridge 13 and the first output terminal 123 of the rectifier bridge 12, and the negative pole of the bus capacitor 14 is connected between the second input terminal 132 of the three-phase inverter bridge 13 and the second output terminal 124 of the rectifier bridge 12.

[0041] The bus capacitor 14 is a capacitor located in a power electronic device and is used to smooth and stabilize the current and voltage of a DC power supply. That is, the bus capacitor 14 of the present application is used to smooth and stabilize the current output by the rectifier bridge 12.

[0042] The positive pole of the bus capacitor 14 is connected to the high side of the three-phase inverter bridge 13 and the rectifier bridge 12 to provide stable current and voltage for the three-phase inverter bridge 13 and the rectifier bridge 12; the negative pole of the bus capacitor 14 is connected to the low side of the three-phase inverter bridge 13 and the rectifier bridge 12.

[0043] The leakage detection circuit 15 is arranged between the rectifier bridge 12 and the electromagnetic anti-interference circuit 11, or between the three-phase inverter bridge 13 and the rectifier bridge 12, and is used to obtain a detection voltage.

[0044] Among them, the leakage detection circuit 15 is used to detect the leakage current to the ground, that is, to detect the ground short-circuit situation.

[0045] The leakage detection circuit 15 can be arranged between the rectifier bridge 12 and the electromagnetic anti-interference circuit 11 or between the three-phase inverter bridge 13 and the rectifier bridge 12, and is used to detect the ground short-circuit situation of the subsequent circuit of the leakage detection circuit 15. Among them, the subsequent circuit of the leakage detection circuit 15 can be the rectifier bridge 12, the three-phase inverter bridge 13, the bus capacitor 14 or the motor 17.

[0046] The control module 16 is respectively connected to the leakage detection circuit 15 and the three-phase inverter bridge 13, and is used to control the three-phase inverter bridge 13 to stop working and generate a first alarm signal when the detection voltage exceeds a preset voltage threshold.

[0047] Among them, the preset voltage threshold is a voltage level set in advance in a power system or a power device. It is a reference value used to judge whether the voltage is within a safe range. When the voltage exceeds the preset voltage threshold, equipment failure or abnormal conditions may occur.

[0048] The control module 16 is a component or system responsible for monitoring and controlling the device, which performs corresponding control actions and generates warning signals according to preset logic and algorithms. In this embodiment, the control module may optionally include, but is not limited to, a microcontroller unit (MCU), a field programmable gate array (FPGA), a digital signal processor (DSP), and a programmable logic device (PLD).

[0049] The first warning signal is a signal sent by the control module 16, which is used to indicate an abnormal situation in the device.

[0050] The task of the control module 16 is to monitor the voltage and take control measures when the voltage exceeds the preset voltage threshold. When the voltage exceeds the preset threshold, the control module 16 will send a stop signal to control the three-phase inverter bridge 13 to stop working. In addition, it will also generate a first alarm signal to notify relevant personnel that an abnormal situation has occurred in the device.

[0051] The electromagnetic anti-interference circuit 11 of this embodiment receives the commercial power, rectifies it through the rectifier bridge 12 and then outputs it to the three-phase inverter bridge 13, and the three-phase inverter bridge 13 processes the output to drive the motor 17 to operate. By setting the leakage detection circuit 15 between the rectifier bridge 12 and the electromagnetic anti-interference circuit 11 or between the three-phase inverter bridge 13 and the rectifier bridge 12, the leakage detection circuit 15 can detect the ground short-circuit situation of the subsequent circuit at its location and output the detection result to the control module 16. The control module 16 judges that a ground short-circuit situation has occurred and controls the three-phase inverter bridge 13 to stop working. It can be seen that by setting the leakage detection circuit 15 at different positions, the ground short-circuit situations at different positions can be quickly detected and judged, so as to protect the safety of the device and personnel in time.

[0052] According to some embodiments of the present application, as Figure 1 shown, the leakage detection circuit 15 of this embodiment includes a zero-sequence current transformer 151, a first sampling resistor R1, and a first sampling circuit 152.

[0053] Among them, one end of the zero-sequence current transformer 151 is respectively connected to one end of the first sampling resistor R1 and one end of the first sampling circuit 152, the other end of the zero-sequence current transformer 151 is respectively connected to the other end of the first sampling resistor R1 and the other end of the first sampling circuit 152, and the control module 16 is connected to the first sampling circuit 152.

[0054] The zero-sequence current transformer 151 is a current sensor used to measure the zero-sequence current in a power device or power system. The zero-sequence current transformer 151 usually consists of a pair of coils. One coil conducts the current, and the other coil measures the current signal. The zero-sequence current transformer 151 can be used to detect the fault current or unbalanced current in a power device or power system to achieve system protection and control.

[0055] The primary winding of the zero-sequence current transformer 151 is connected in series to the alternating current between the rectifier bridge 12 and the electromagnetic anti-interference circuit 11. Both ends of the secondary winding are connected to the first sampling resistor R1 and the first sampling circuit 152. The first sampling resistor R1 is used to discharge the current induced in the secondary winding, and the first sampling circuit 152 is used to compare or amplify the voltage across the first sampling resistor R1 and transmit the compared or amplified voltage signal to the control module 16.

[0056] In this embodiment, when detecting the leakage current generated to the ground, by adding the zero-sequence current transformer 151 in front of the first sampling resistor R1, the normal operating state of the leakage current is in the milliamperes level. At this time, a leakage protection threshold at the milliamperes level can be set, with sensitive protection, which can safely and effectively protect the electric shock personnel and can also quickly protect the short-circuited equipment to prevent further damage to the equipment.

[0057] According to some embodiments of the present application, the current detection device 10 further includes a ground wire. The zero-sequence current transformer 151 is used to generate a current when the rectifier bridge 12 or the bus capacitor 14 or the three-phase inverter bridge 13 or the motor 17 leaks electricity relative to the ground wire. The induction winding of the zero-sequence current transformer generates an induced current, and the induced current flows through the first sampling resistor R1 to generate a voltage. The first sampling circuit 152 is used to collect the voltage to obtain the detected voltage.

[0058] Among them, the ground wire is the grounding wire in a power system or power device, used to provide a safe grounding path for the circuit. In the current detection device 10, the ground wire plays the role of connecting the circuit to the ground so that when a leakage or other fault occurs, the change in current can be detected in a timely manner.

[0059] The leakage detection circuit 15 is arranged between the first input terminal 121 of the rectifier bridge 12 and the first output terminal 111 of the electromagnetic anti-interference circuit 11 and between the second input terminal 122 of the rectifier bridge 12 and the second output terminal 112 of the electromagnetic anti-interference circuit 11. The connection line between the first input terminal 121 of the rectifier bridge 12 and the first output terminal 111 of the electromagnetic anti-interference circuit 11 and the connection line between the second input terminal 122 of the rectifier bridge 12 and the second output terminal 112 of the electromagnetic anti-interference circuit 11 pass through the zero-sequence current transformer 151.

[0060] The leakage detection circuit 15 detects the subsequent stage circuit where the zero-sequence current transformer 151 is located, that is, the leakage current of the rectifier bridge 12, the bus capacitor 14, the three-phase inverter bridge 13 or the motor 17 to the ground. This leakage current is at the milliampere level under normal operating conditions. If the subsequent stage circuit discharges to the ground and the leakage current is greater than a set threshold value, the magnetic core of the zero-sequence current transformer 151 induces a magnetic field, and the secondary winding wound around the magnetic core induces a corresponding current. After the current flows through the first sampling resistor R1, a voltage is generated, and then it is compared or amplified by the first sampling circuit 152. Among them, the set threshold value is at the milliampere level, and the optional values include but are not limited to 30 mA, 40 mA, and 50 mA.

[0061] The first sampling circuit 152 transmits the voltage signal after comparison or amplification to the control module 16. If the voltage after comparison or amplification exceeds the preset voltage threshold value, the control module 16 determines that a short circuit to the ground has occurred, controls the three-phase inverter bridge 13 to stop working, and issues a first alarm signal. It can quickly cut off the short-circuit loop to the ground, thereby protecting the safety of the motor equipment and personnel. In addition, relevant personnel can quickly locate and troubleshoot problems based on the first alarm signal, improving the intelligence of the servo driver.

[0062] According to some embodiments of the present application, the current detection device 10 further includes an overcurrent detection circuit 18, which is arranged between the negative electrode of the bus capacitor 14 and the second input terminal 132 of the three-phase inverter bridge 13.

[0063] The overcurrent detection circuit 18 is used for short-circuit protection of the bridge arm of the three-phase inverter bridge 13 or short-circuit protection between phases of the output of the three-phase inverter bridge 13.

[0064] According to some embodiments of the present application, the overcurrent detection circuit 18 includes a second sampling resistor R2 and a second sampling circuit 181. One end of the second sampling resistor R2 is connected to the negative electrode of the bus capacitor 14, the other end of the second sampling resistor R2 is connected to the second input terminal 132 of the three-phase inverter bridge 13, and the second sampling circuit 181 is respectively connected to both ends of the second sampling resistor R2.

[0065] When a short circuit occurs in the bridge arm of the three-phase inverter bridge 13 or a short circuit occurs between phases of the output of the three-phase inverter bridge 13, a large current flows through the second sampling resistor R2. After the second sampling circuit 181 detects the short-circuit large current, the control module 16 controls the three-phase inverter bridge 13 to stop working, thereby cutting off the short-circuit loop and protecting the safety of the motor equipment and personnel. It should be noted that the specific circuit design of the second sampling circuit 181 is not limited in this application.

[0066] According to some embodiments of the present application, the control module 16 is connected to the second sampling circuit 181, and is used to control the three-phase inverter bridge 13 to stop working when the detected current of the second sampling circuit 181 is greater than the preset current threshold value, and generate a second alarm signal.

[0067] Among them, the preset current threshold refers to the current value preset in a power system or electronic device, which is used to trigger a certain protection or control mechanism. When the current exceeds or reaches the preset current threshold, the corresponding protection or control device will be activated to perform corresponding actions.

[0068] In this application, by setting the leakage detection circuit 15 at different positions of the circuit and the overcurrent detection circuit 18 on the low side of the circuit, different short - circuit situations in the circuit can be quickly detected, and the protection functions of the leakage detection circuit 15 and the overcurrent detection circuit 18 do not overlap. They each perform their own functions, avoiding waste of costs and resources.

[0069] Please refer to Figure 2 as shown in Figure 2 Fig. is a circuit architecture example diagram of another current detection device provided by this application. The difference between the current detection device 10 in this embodiment and the current detection device 10 in Figure 1 is as follows:

[0070] The leakage detection circuit 15 is arranged between the first input terminal 131 of the three - phase inverter bridge 13 and the first output terminal 123 of the rectifier bridge 12, and between the second input terminal 132 of the three - phase inverter bridge 13 and the second output terminal 124 of the rectifier bridge 12. The connection lines between the first output terminal 123 of the rectifier bridge 12 and the positive electrode of the bus capacitor 14, and between the second output terminal 124 of the rectifier bridge 12 and the negative electrode of the bus capacitor pass through the zero - sequence current transformer 151. That is, both the high - side connection line and the low - side connection line between the rectifier bridge 12 and the bus capacitor 14 pass through the zero - sequence current transformer 151.

[0071] The leakage detection circuit 15 detects the leakage current of the subsequent - stage circuit bus capacitor 14, three - phase inverter bridge 13 or motor 17 to the ground at the position where the zero - sequence current transformer 151 is located. Among them, the rectifier bridge 12 converts three - phase alternating current into direct current and stores electrical energy through the bus capacitor 14. In this case, the zero - sequence current transformer 151 in the leakage detection circuit 15 can be replaced by a zero - sequence current transformer of two phases instead of three phases, thus saving costs and space and simplifying the circuit design.

[0072] Please refer to Figure 3 as shown in Figure 3 Fig. is a circuit architecture example diagram of yet another current detection device provided by this application. The difference between the current detection device 10 in this embodiment and the current detection device 10 in Figure 1 is as follows:

[0073] The leakage detection circuit 15 is disposed between the first input terminal 131 of the three-phase inverter bridge 13 and the first output terminal 123 of the rectifier bridge 12, and between the second input terminal 132 of the three-phase inverter bridge 13 and the second output terminal 124 of the rectifier bridge 12. The connection line between the positive electrode of the bus capacitor 14 and the first input terminal 131 of the three-phase inverter bridge 13 and the connection line between the negative electrode of the bus capacitor 14 and the second input terminal 132 of the three-phase inverter bridge 13 are passed through the zero-sequence current transformer 151. That is, both the high-side connection line and the low-side connection line between the bus capacitor 14 and the three-phase inverter bridge 13 are passed through the zero-sequence current transformer 151.

[0074] The leakage detection circuit 15 is used to detect the leakage current of the three-phase inverter bridge 13 or the motor 17 in the subsequent circuit where the zero-sequence current transformer 151 is located to the ground. At this time, the zero-sequence current transformer 151 in the leakage detection circuit 15 can be replaced by zero-sequence current transformers of two phases instead of three phases, thereby saving cost and space and simplifying the circuit design.

[0075] Another embodiment of the present application further provides a servo driver device, and the servo driver device includes the current detection device 10 of the above embodiment.

[0076] The above are only the embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A current detection device, characterized in that: include: An electromagnetic anti-interference circuit, wherein an input end of the electromagnetic anti-interference circuit receives a mains current; A rectifier bridge, wherein a first input end of the rectifier bridge is connected to a first output end of the electromagnetic anti-interference circuit, and a second input end of the rectifier bridge is connected to a second output end of the electromagnetic anti-interference circuit; A three-phase inverter bridge, wherein a first input end of the three-phase inverter bridge is connected to a first output end of the rectifier bridge, a second input end of the three-phase inverter bridge is connected to a second output end of the rectifier bridge, and an output end of the three-phase inverter bridge is connected to a motor; A bus capacitor, wherein the positive electrode of the bus capacitor is connected between the first input end of the three-phase inverter bridge and the first output end of the rectifier bridge, and the negative electrode of the bus capacitor is connected between the second input end of the three-phase inverter bridge and the second output end of the rectifier bridge; A leakage detection circuit is arranged between the rectifier bridge and the electromagnetic anti-interference circuit, or between the three-phase inverter bridge and the rectifier bridge, and is used to obtain a detection voltage; The control module is connected to the leakage detection circuit and the three-phase inverter bridge respectively, and is used to control the three-phase inverter bridge to stop working and generate a first alarm signal when the detection voltage exceeds a preset voltage threshold.

2. The current detection device according to claim 1, characterized in that: The leakage detection circuit includes a zero-sequence current transformer, a first sampling resistor and a first sampling circuit, one end of the zero-sequence current transformer is respectively connected to one end of the first sampling resistor and one end of the first sampling circuit, the other end of the zero-sequence current transformer is respectively connected to the other end of the first sampling resistor and the other end of the first sampling circuit, and the control module is connected to the first sampling circuit.

3. The current detection device according to claim 2, characterized in that: The current detection device also includes a ground wire, the zero-sequence current transformer is used to generate current when the rectifier bridge or the bus capacitor or the three-phase inverter bridge or the motor leaks relative to the ground wire, the induction winding of the zero-sequence current transformer generates an induced current, the induced current flows through the first sampling resistor to generate a voltage, and the first sampling circuit is used to collect the voltage to obtain the detection voltage.

4. The current detection device according to claim 2, characterized in that: The leakage detection circuit is arranged between the first input end of the rectifier bridge and the first output end of the electromagnetic anti-interference circuit and between the second input end of the rectifier bridge and the second output end of the electromagnetic anti-interference circuit. The connecting line between the first input end of the rectifier bridge and the first output end of the electromagnetic anti-interference circuit and the connecting line between the second input end of the rectifier bridge and the second output end of the electromagnetic anti-interference circuit are passed through the zero-sequence current transformer.

5. The current detection device according to claim 2, characterized in that: The leakage detection circuit is arranged between the first input end of the three-phase inverter bridge and the first output end of the rectifier bridge and between the second input end of the three-phase inverter bridge and the second output end of the rectifier bridge. The connecting line between the first output end of the rectifier bridge and the positive electrode of the bus capacitor and the connecting line between the second output end of the rectifier bridge and the negative electrode of the bus capacitor are passed through the zero-sequence current transformer.

6. The current detection device according to claim 2, characterized in that: The leakage detection circuit is arranged between the first input end of the three-phase inverter bridge and the first output end of the rectifier bridge and between the second input end of the three-phase inverter bridge and the second output end of the rectifier bridge. The connecting line between the positive electrode of the bus capacitor and the first input end of the three-phase inverter bridge and the connecting line between the negative electrode of the bus capacitor and the second input end of the three-phase inverter bridge are passed through the zero-sequence current transformer.

7. The current detection device according to any one of claims 1 to 6, characterized in that: The current detection device also includes an overcurrent detection circuit, which is arranged between the negative electrode of the bus capacitor and the second input terminal of the three-phase inverter bridge.

8. The current detection device according to claim 7, characterized in that: The overcurrent detection circuit includes a second sampling resistor and a second sampling circuit, one end of the second sampling resistor is connected to the negative electrode of the bus capacitor, the other end of the second sampling resistor is connected to the second input end of the three-phase inverter bridge, and the second sampling circuit is respectively connected to the two ends of the second sampling resistor.

9. The current detection device according to claim 8, characterized in that: The control module is connected to the second sampling circuit, and is used to control the three-phase inverter bridge to stop working and generate a second alarm signal when the detection current of the second sampling circuit is greater than a preset current threshold.

10. A servo drive device, characterized in that: The servo drive device comprises: a current detection device as described in any one of claims 1-9.

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