Composite application circuit based on high-voltage voltage sampling and high-voltage current sampling
Through the use of isolation switch logic switching and signal isolation transformers, composite sampling of high voltage voltage and current is achieved, which solves the problems of high cost and complexity in existing technologies, reduces system costs and improves sampling accuracy and rate.
Patent Information
- Application Number
- CN202510937956.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2025-10-21
AI Technical Summary
In the existing technology, high-voltage voltage and current sampling systems are costly, have many components, have high failure rates, and are large and complex, making it difficult to achieve high-precision and fast sampling.
The parameter value sampling of total voltage and total current is realized through the logic switching of the isolation switch. The high-voltage area and the low-voltage area are connected by an isolation transformer. The signal is isolated by using a relay drive switch and a signal isolation transformer to realize the composite sampling of voltage and current.
It reduces the communication isolation cost, simplifies the control strategy, reduces the system cost, and realizes the independent sampling of high voltage voltage and current, which improves the sampling accuracy and rate.
Smart Images
Figure CN120820748A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of voltage and current sampling, and in particular relates to a composite application circuit based on high-voltage voltage sampling and high-voltage current sampling. Background Art
[0002] With the development of the new energy industry, battery systems are gaining wider application in automotive and energy storage applications. As battery capacity continues to increase, systems are becoming increasingly complex. Multiple series and parallel clusters, along with the involvement of photovoltaic systems, PCS systems, EMS systems, BMS systems, and other devices, are contributing to the increasing size of energy storage systems. Cost control and production risk requirements are becoming increasingly prominent. Sampling total system voltage and total current are essential parameters, requiring topologies with higher accuracy and sampling rates. This, in turn, significantly increases costs, making cost reduction solutions urgent.
[0003] Prior art see Figure 1 This is a traditional high-voltage sampling system. The system consists of a primary power module UP1, an isolated power module UP2, an isolated voltage regulator T1, an MCU microcontroller unit, an isolated communication module OP1, a sampling module and peripheral circuits, a switch relay K1, and high-voltage sampling resistors R1, R2, R3, R4, and R5 for total system voltage sampling. The system also consists of a primary power module UP3, an isolated power module UP4, an isolated voltage regulator T2, an isolated communication module OP2, a sampling module and peripheral circuits, and high-voltage sampling resistors R5, R6, and RCS1 for current sampling. The entire system aggregates system data under a control unit, with each unit operating independently. This results in a high cost for the sampling unit, requiring multiple components, resulting in high risks and failure rates, and high production costs. Summary of the Invention
[0004] In order to solve the above problems, the present invention realizes parameter value sampling of total voltage and total current through logical switching of isolation switches, and simultaneously displays that the voltage and current sampling signals are completely isolated.
[0005] The specific technical solution includes a battery unit and a BMS high-voltage sampling unit. The BMS high-voltage sampling unit includes a high-voltage area and a low-voltage area. The two are connected through an isolation transformer. The high-voltage area collects voltage and transmits it to the low-voltage area for current conversion. The high-voltage area is connected to the battery unit. The low-voltage area includes an MCU, a communication module, an interface module, and an isoSPI communication converter. The high-voltage area includes a sampling module, an analog front-end module, a high-voltage signal switch relay, a relay drive switch, a high-voltage sampling shunt resistor, and a high-voltage shunt resistor. Among them, the drain of the relay drive switch is connected to the high-voltage signal switch relay, the gate of the relay drive switch is connected to the analog front-end module, and the high-voltage signal switch relay isolates the total voltage sampling and current sampling.
[0006] Preferably, data transmission is performed between the high-voltage area and the low-voltage area by sampling a daisy chain isoSPI through a signal isolation transformer.
[0007] Preferably, the MCU outputs a four-wire SIP signal which is converted into a two-wire isoSPI signal through an isoSPI communication converter.
[0008] Preferably, the sampling module reads the voltage across the sampling resistor and converts it into a digital value for transmission to the analog front-end module.
[0009] Preferably, the analog front-end module and the sampling module transmit signals via I2C.
[0010] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The independent sampling module samples two key parameter values of the system, total voltage and total current; 2. The cost of communication isolation is reduced, there are many implementation methods, the process requirements are simpler, and the system cost is lower; 3. The control strategy is simple, and only the switching of the switch relay is used to complete the battery module high-voltage sampling and loop current sampling. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 This is a circuit diagram of a battery sampling module in the prior art; Figure 2 This is a circuit diagram of a single-chip microcomputer master control and level conversion circuit based on a high-voltage voltage sampling and high-voltage current sampling composite application circuit according to a specific embodiment of the present invention. DETAILED DESCRIPTION
[0012] The technical solution provided by the present invention will be further described below with reference to the accompanying drawings.
[0013] See also Figure 2 , as shown in the figure, the specific technical solution of the present invention includes a battery part 11 and a BMS high-voltage sampling unit 20. The BMS high-voltage sampling unit 20 includes a high-voltage area 21 and a low-voltage area 22, which are connected through an isolation transformer. The high-voltage area 21 collects voltage and transmits it to the low-voltage area 22 for current conversion. The high-voltage area 21 is connected to the battery part 11, and the low-voltage area 22 includes an MCU, a communication module, an interface module and an isoSPI communication converter. The high-voltage area 21 includes a sampling module, an analog front-end module, a high-voltage signal switch relay K1, a relay drive switch Q1, a high-voltage sampling shunt resistor and a high-voltage shunt resistor; wherein, the drain of the relay drive switch Q1 is connected to the high-voltage signal switch relay K1, and the gate of the relay drive switch Q1 is connected to the analog front-end module. The high-voltage signal switch relay K1 isolates the total voltage sampling and current sampling.
[0014] The high-voltage section samples the system current and total voltage of the main circuit of battery section 11, collecting data through a sampling interface. Within a battery section 11, the system total voltage and total current are equivalent current parameters with different properties. High-voltage signal switch relay K1 isolates total voltage sampling from current sampling. Low-voltage section 22 and high-voltage section 21 are isolated by ultra-high voltage signal isolation transformer T1, which meets national standards for high creepage distance and air resistance of 1500V or above. High-voltage section 21 and low-voltage section 22 are sampled via daisy-chain isoSPI for data transmission via signal isolation transformer T1. The MCU (U1 module) outputs a four-wire SIP signal, which is converted into a two-wire isoSPI signal by the isoSPI communication converter (U4). This data is then transmitted to the UA3 analog front-end module via signal isolation transformer T1. The main system then responds to control the switching frequency and period of K1's switch. The sampling module uses the total system voltage and current sampling values to coordinate the operation of the entire system.
[0015] After the system of the present invention is powered on and initialized, the MCU executes the battery data sampling command. The four-wire SIP signal is converted into a two-wire isoSPI signal through U4 and transmitted to the UA3 analog front-end module through the signal isolation transformer. The UA3 analog front-end module and the UA2 sampling module are transmitted via I2C signals. UA2 directly reads back the voltage signal across the sampling resistor R3, transmits the digital value to the UA3 analog front-end module through the internal ADC converter, and then sends it to the U1 module through the isolation transformer T1 and U4. The U1 module converts the data into system voltage data through resistance ratio conversion and reports it to the main controller. After a timed delay of t0, the U1 module transmits the data back to the UA3 analog front-end module. The UA3 analog front-end module executes the command to control the I / O1 pin, outputs a high level, and the relay drives the switch Q1 to turn on. The K1 action switch switches to the S1 port, delaying t1 time. UA2 directly reads back the voltage signal in parallel at both ends of R3 and RCS1. The UA2 sampling module reads the current signal, amplifies it, and then transmits the digital quantity to UA3 through the internal ADC converter, and then sends it to the U1 module through the isolation transformer T1 and U4. The U1 module converts the data into bus current data through the small voltage value and the shunt resistance value and reports it to the main controller. In this way, the switching of the high-voltage sampling of the battery part 11 and the loop current sampling is completed.
[0016] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.
[0017] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A composite application circuit based on high voltage sampling and high voltage current sampling, including a battery unit and a BMS high voltage sampling unit, characterized in that: The BMS high-voltage sampling unit includes a high-voltage area and a low-voltage area, which are connected through an isolation transformer. The high-voltage area collects voltage and transmits it to the low-voltage area for current conversion. The high-voltage area is connected to the battery part. The low-voltage area includes an MCU, a communication module, an interface module and an isoSPI communication converter. The high-voltage area includes a sampling module, an analog front-end module, a high-voltage signal switch relay, a relay drive switch, a high-voltage sampling shunt resistor and a high-voltage shunt resistor; Among them, the drain of the relay drive switch is connected to the high-voltage signal switch relay, the gate of the relay drive switch is connected to the analog front-end module, and the high-voltage signal switch relay isolates the total voltage sampling and current sampling.
2. The composite application circuit based on high voltage sampling and high voltage current sampling according to claim 1, characterized in that: The high voltage area and the low voltage area are connected via a signal isolation transformer sampling daisy chain isoSPI for data transmission.
3. The composite application circuit based on high voltage sampling and high voltage current sampling according to claim 1, characterized in that: The MCU outputs a four-wire SIP signal which is converted into a two-wire isoSPI signal through an isoSPI communication converter.
4. The composite application circuit based on high voltage sampling and high voltage current sampling according to claim 1, characterized in that: The sampling module reads the voltage across the sampling resistor and converts it into a digital value for transmission to the analog front-end module.
5. The composite application circuit based on high voltage sampling and high voltage current sampling according to claim 1, characterized in that: The analog front-end module and the sampling module transmit signals via I2C.