High-voltage frequency converter sampling circuit adopting Hall sensor
Through Hall sensor and digital signal processing technology, the problems of low current sampling accuracy and high cost of high voltage inverters are solved, high-precision and low-cost current detection and isolation are achieved, and the stability and reliability of the inverter are improved.
Patent Information
- Application Number
- CN202411361264.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2025-01-10
AI Technical Summary
The current sampling method of existing high-voltage inverters uses CT measurement, which has problems such as low accuracy, high cost and inability to effectively isolate large currents, which affects equipment and personal safety.
Hall sensors are used to combine sampling and follow circuits, isolation amplifier circuits, composite follow circuits and CPU digital signal processing chips to achieve high-precision current detection and isolation through Hall effect processing and digital modulation.
It realizes high-precision and low-cost current detection, ensures equipment and personal safety, and improves the stability and reliability of the inverter.
Smart Images
Figure CN119291281A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of high-voltage inverter current sampling, and in particular relates to a high-voltage inverter sampling circuit using a Hall sensor. Background Art
[0002] In nuclear power plants, the main pump inverter is a key component for the main pump power supply. If the main pump inverter fails and trips, the main pump will lose power, which will cause the reactor to shut down. As the core equipment for the operation of the main pump, the inverter has high requirements for reliability and stability. There are also high requirements for the detection and protection of each input and output quantity of the high-voltage inverter. Among them, the input and output current detection of the high-voltage inverter involves a large current of 800A. In addition to ensuring accuracy, its detection method must also pay attention to the isolation of large currents in order to protect equipment and personal safety.
[0003] In the prior art, the most common way to sample the current of a high-voltage inverter is to use CT for measurement, but this method has the following disadvantages: 1. Due to the limitation of CT itself, its sampling accuracy is lower than that of the Hall sensor. 2. Based on Hall sampling, non-contact measurement isolates large currents, effectively protecting equipment and personal safety. 3. Both the input and output of the inverter need to be detected by CT, which is costly.
[0004] Therefore, developing a high-voltage inverter sampling circuit using a Hall sensor is of great significance to improving the operating stability and reliability of the inverter. Summary of the invention
[0005] The object of the present invention is to provide a high-voltage inverter sampling circuit using a Hall sensor, which has the advantages of high detection accuracy, simple circuit structure, high device integration effect and low cost.
[0006] In order to achieve the above object, the technical solution adopted by the present invention is:
[0007] A high-voltage inverter sampling circuit using a Hall sensor comprises a Hall sensor, a sampling follower circuit, an isolation amplifier circuit, a composite follower circuit, a protection comparison circuit and a CPU digital signal processing chip; the high-voltage inverter, the Hall sensor, the sampling follower circuit, the isolation amplifier circuit, the composite follower circuit and the CPU digital signal processing chip are connected in sequence, the composite follower circuit is connected to the protection comparison circuit, and the protection comparison circuit is connected to the CPU digital signal processing chip.
[0008] The Hall sensor collects the operating current signal C of the high-voltage inverter and sends a potential signal CR to the sampling follower circuit after Hall effect processing.
[0009] The sampling follower circuit receives the potential signal CR from the Hall sensor and transmits the signal 1:1 to the isolation amplifier circuit through the retainer inside the circuit.
[0010] The isolation amplifier built in the isolation amplifier circuit performs duty cycle modulation and demodulation on the voltage CR1 buffered by the sampling follower circuit to obtain an analog signal U that meets the requirements of the CPU digital signal processing chip.
[0011] The digitally modulated analog signal U is transmitted to the composite follower circuit for buffering to obtain intermediate signals U1 and U2.
[0012] U1 sends it to the protection comparison circuit, and U2 sends it to the CPU digital signal processing chip.
[0013] After U1 is sent to the protection comparison circuit, it is compared with the preset value in the circuit through the internal comparator of the protection comparison circuit. If it is greater than the comparison value, a low level is output to generate an overcurrent alarm signal FO1 and send it to the CPU digital signal processing chip.
[0014] The beneficial effects achieved by the present invention are:
[0015] The present invention processes the large current into a small signal through the sampling of the Hall sensor, and the sampling follower circuit performs buffer bias processing on the voltage after the small signal processing, thereby performing 1:1 transmission to ensure that the voltage before and after is consistent and the distortion is low, and at the same time, the isolation of the high and low voltage parts is realized to protect the main control chip from being burned by the large current. The voltage after digital modulation by the isolation amplifier circuit is sent to the composite follower circuit, and one voltage is sent to the protection comparison circuit, so that the control system monitors the current of the high-voltage inverter in real time to realize overcurrent protection. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 The figure is a block diagram of a high-voltage inverter sampling circuit using a Hall sensor. DETAILED DESCRIPTION
[0017] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.
[0018] like Figure 1 As shown, a high-voltage inverter sampling circuit using a Hall sensor includes: a Hall sensor, a sampling follower circuit, an isolation amplifier circuit, a composite follower circuit, a protection comparison circuit and a CPU digital signal processing chip; the high-voltage inverter, the Hall sensor, the sampling follower circuit, the isolation amplifier circuit, the composite follower circuit, and the CPU digital signal processing chip are connected in sequence, the composite follower circuit is connected to the protection comparison circuit, and the protection comparison circuit is connected to the CPU digital signal processing chip.
[0019] The Hall sensor collects the operating current signal C of the high-voltage inverter, and sends out an electric potential signal CR to the sampling follower circuit after Hall effect processing; the sampling follower circuit receives the electric potential signal CR from the Hall sensor, and transmits the signal to the isolation amplifier circuit in a 1:1 manner through the retainer inside the circuit. The isolation amplifier built into the isolation amplifier circuit performs duty cycle modulation and demodulation on the voltage CR1 buffered by the sampling follower circuit to obtain an analog signal U that meets the requirements of the CPU digital signal processing chip; the analog signal U after digital modulation is transmitted to the composite follower circuit for buffering to obtain an intermediate signal U1 and U2, U1 is sent to the protection comparison circuit, and U2 is sent to the CPU digital signal processing chip. After U1 is sent to the protection comparison circuit, it is compared with the preset value in the circuit by the comparator inside the protection comparison circuit. If it is greater than the comparison value, a low level is output to generate an overcurrent alarm signal FO1 to be sent to the CPU digital signal processing chip.
[0020] The Hall sensor is connected to the high-voltage inverter to collect the current signal, and sends the collected current signal to the sampling follower circuit through the potential change. The sampling follower circuit is connected to the Hall sampling feedback signal, and has a built-in retainer to buffer and bias the voltage output by the Hall sensor, so that its output voltage is consistent with the received input voltage. The isolation amplifier circuit is connected to the sampling follower circuit, and the buffered voltage is modulated and demodulated by the duty cycle to obtain the pin voltage of the digital analog signal that meets the digital signal processing chip. The composite follower circuit is connected to the isolation amplifier circuit, and the pin voltage of the isolation amplifier circuit is buffered and biased to ensure that it is consistent with the received input voltage. The protection comparison circuit, a pin voltage derived from the composite follower circuit, participates in the protection comparison, so that the control system can monitor the current of the high-voltage inverter in real time to achieve overcurrent protection.
Claims
1. A high-voltage inverter sampling circuit using a Hall sensor, characterized in that: It includes a Hall sensor, a sampling follower circuit, an isolation amplifier circuit, a composite follower circuit, a protection comparison circuit and a CPU digital signal processing chip; a high-voltage frequency converter, a Hall sensor, a sampling follower circuit, an isolation amplifier circuit, a composite follower circuit and a CPU digital signal processing chip are connected in sequence, the composite follower circuit is connected to the protection comparison circuit, and the protection comparison circuit is connected to the CPU digital signal processing chip.
2. The high-voltage inverter sampling circuit using a Hall sensor according to claim 1, characterized in that: The Hall sensor collects the operating current signal C of the high-voltage inverter and sends a potential signal CR to the sampling follower circuit after Hall effect processing.
3. The high-voltage inverter sampling circuit using a Hall sensor according to claim 2, characterized in that: The sampling follower circuit receives the potential signal CR from the Hall sensor and transmits the signal 1:1 to the isolation amplifier circuit through the retainer inside the circuit.
4. The high-voltage inverter sampling circuit using a Hall sensor according to claim 3 is characterized in that: The isolation amplifier built in the isolation amplifier circuit performs duty cycle modulation and demodulation on the voltage CR1 buffered by the sampling follower circuit to obtain an analog signal U that meets the requirements of the CPU digital signal processing chip.
5. The high-voltage inverter sampling circuit using a Hall sensor according to claim 4, characterized in that: The digitally modulated analog signal U is transmitted to the composite follower circuit for buffering to obtain intermediate signals U1 and U2.
6. The high-voltage inverter sampling circuit using a Hall sensor according to claim 5, characterized in that: U1 sends it to the protection comparison circuit, and U2 sends it to the CPU digital signal processing chip.
7. The high-voltage inverter sampling circuit using a Hall sensor according to claim 6, characterized in that: After U1 is sent to the protection comparison circuit, it is compared with the preset value in the circuit through the internal comparator of the protection comparison circuit. If it is greater than the comparison value, a low level is output to generate an overcurrent alarm signal FO1 and send it to the CPU digital signal processing chip.