CN114384303A - Novel current sampling method based on MOS voltage drop - Google Patents

一种基于MOS压降的新型电流采样方法，包括以下步骤：利用热仿真推算不同使用条件下，温度采样点和MOS管结温之间的关系表，运行中根据实测或工作实际的损耗、电流、温度条件获取MOS管结温，基于MOS管结温获取导通电阻Rdson，采样获取对应的桥臂电压并与导通电阻计算获得电流。基于对MOS管结温与采样设备采集的MOS管工作环境温度的不同以及不同损耗、电流对MOS管结温带来的不同影响的考虑相较于直接使用温度采样器的温度采样结果来作为MOS管内阻计算基础来说更加符合电流的真实值，消除了大量的误差，对后续的计算处理控制工作提供了很好的基础数值保障。

A new current sampling method based on MOS voltage drop, including the following steps: using thermal simulation to calculate the relationship table between the temperature sampling point and the junction temperature of the MOS tube under different conditions of use, and according to the actual measurement or work actual loss, current during operation 、Temperature conditions to obtain the junction temperature of the MOS tube, obtain the on-resistance Rdson based on the junction temperature of the MOS tube, sample and obtain the corresponding bridge arm voltage and calculate the current with the on-resistance. Based on the consideration of the difference between the junction temperature of the MOS tube and the working environment temperature of the MOS tube collected by the sampling device, as well as the different effects of different losses and currents on the junction temperature of the MOS tube On the basis of resistance calculation, it is more in line with the real value of the current, eliminates a large number of errors, and provides a good basic numerical guarantee for the subsequent calculation and control work.

一种基于MOS压降的新型电流采样方法A Novel Current Sampling Method Based on MOS Voltage Drop

技术领域technical field

本发明涉及数据采样领域，尤其涉及一种基于MOS压降的新型电流采样方法。The invention relates to the field of data sampling, in particular to a novel current sampling method based on MOS voltage drop.

背景技术Background technique

在电机驱动器电流采样方案中，为考虑成本，一般会采用桥臂中串联电阻或者基于MOS管压降电流计算方式，但是当电流过大时，电阻上发热情况越发严重，影响整机的效率，MOS管压降的方式如果不进行补偿，采样精度往往很难得到保证。第二种方案精度差的原因是，在使用中，由于MOSFET自身温度特性导致内阻变化，从而导致压降的变化，使得采样电流与实际电流出现较大的偏差，无法通过采样电流值实现正常的控制。In the current sampling scheme of the motor driver, in order to consider the cost, the series resistance in the bridge arm or the current calculation method based on the voltage drop of the MOS tube is generally used. If the MOS tube voltage drop method is not compensated, the sampling accuracy is often difficult to guarantee. The reason for the poor accuracy of the second solution is that in use, the internal resistance changes due to the temperature characteristics of the MOSFET itself, which leads to changes in the voltage drop, resulting in a large deviation between the sampling current and the actual current, which cannot be achieved by sampling the current value. control.

中国专利CN 108768139A公开了一种压降型功率级电路中电流检测误差补偿方法及电路，采样抵消电压，并作为反馈信号反馈到电流采样模块；所述抵消电压作为输入信号补偿抵消功率MOS器件上的寄生电感带来的干扰信号。将抵消电压作为反馈信号反馈到电流采样模块，作为输入信号补偿，能够用于抵消由于功率级电路寄生电感所带来的干扰，从而得到更准确的电流过O检测信号和电流过大信号。Chinese patent CN 108768139A discloses a current detection error compensation method and circuit in a voltage drop type power stage circuit. The offset voltage is sampled and fed back to the current sampling module as a feedback signal; the offset voltage is used as an input signal to compensate and offset the power MOS device. The interference signal caused by the parasitic inductance. The offset voltage is fed back to the current sampling module as a feedback signal, as input signal compensation, which can be used to offset the interference caused by the parasitic inductance of the power stage circuit, so as to obtain a more accurate current over-O detection signal and over-current signal.

中国专利CN 102495265B公开了一种MOSFET开关元件的电流采样电路，所述开关元件的第一端和采样模块的第一输入端相连，并作为电流输入信号端，所述开关元件的第二端和采样模块的第二输入端相连，并作为MOSFET开关元件电流输出信号端，所述采样模块的输出端作为采样电流输出信号端，所述采样模块直接采样MOSFET开关元件的第一端和第二端的电压差，所述采样模块的第一输入端和第二输入端之间可允许的最大电压差值为采样模块两个输入端之间的耐压值；所述采样模块包括的钳位模块增加采样模块的耐压值，阻断从采样模块的第一输入端端到第二输入端之间形成电流通路，提高MOSFET开关元件的电流采样电路的工作电压范围。Chinese patent CN 102495265B discloses a current sampling circuit of a MOSFET switching element. The first end of the switching element is connected to the first input end of the sampling module and serves as a current input signal end, and the second end of the switching element is connected to the first input end of the sampling module. The second input terminal of the sampling module is connected and used as the current output signal terminal of the MOSFET switching element, the output terminal of the sampling module is used as the sampling current output signal terminal, and the sampling module directly samples the first terminal and the second terminal of the MOSFET switching element. voltage difference, the maximum allowable voltage difference between the first input end and the second input end of the sampling module is the withstand voltage value between the two input ends of the sampling module; the clamping module included in the sampling module increases The withstand voltage value of the sampling module blocks the formation of a current path from the first input end to the second input end of the sampling module, and improves the working voltage range of the current sampling circuit of the MOSFET switching element.

现有技术中提供了多种电流采样方法，例如通过电阻采样和MOS压降电流采样综合的方法，实现两种电流采样互为补充，优化电流采样精度。而上述两个专利则是分别针对引入电压和提高工作电压范围的角度去提高采样的效率，但是都未对MOSFET温度升高做出补偿，导致在实际工作中的电流采样值会大于实际值。A variety of current sampling methods are provided in the prior art. For example, by combining resistance sampling and MOS voltage drop current sampling, the two current sampling methods can complement each other and optimize the current sampling accuracy. The above two patents aim to improve the sampling efficiency from the perspective of introducing voltage and increasing the operating voltage range, but neither compensates for the temperature rise of the MOSFET, resulting in a current sampling value greater than the actual value in actual work.

本发明在现有硬件方案的基础上采集桥臂中点电压，同时通过引入MOSFET的结温与损耗关系、结温与MOS内阻的关系以及结温与采样点温度的关系，形成对应的函数关系作为补偿公式，带入采样计算电流值中进行使用，实现在不同电流，不同温升的情况下对采样值进行精确补偿，以保证电流采样的精度。The invention collects the midpoint voltage of the bridge arm on the basis of the existing hardware scheme, and simultaneously forms the corresponding function by introducing the relationship between the junction temperature and the loss of the MOSFET, the relationship between the junction temperature and the MOS internal resistance, and the relationship between the junction temperature and the sampling point temperature. The relationship is used as a compensation formula to be used in the sampling and calculation of the current value, so that the sampling value can be accurately compensated under different currents and different temperature rises, so as to ensure the accuracy of the current sampling.

此外，一方面由于对本领域技术人员的理解存在差异；另一方面由于申请人做出本发明时研究了大量文献和专利，但篇幅所限并未详细罗列所有的细节与内容，然而这绝非本发明不具备这些现有技术的特征，相反本发明已经具备现有技术的所有特征，而且申请人保留在背景技术中增加相关现有技术之权利。In addition, on the one hand, there are differences in the understanding of those skilled in the art; on the other hand, because the applicant has studied a large number of documents and patents when making the present invention, but due to space limitations, all details and contents are not listed in detail, but this is by no means The present invention does not possess the features of the prior art, on the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art.

发明内容SUMMARY OF THE INVENTION

针对现有技术之不足，本发明提供了一种基于MOS压降的新型电流采样方法，In view of the deficiencies of the prior art, the present invention provides a novel current sampling method based on MOS voltage drop,

包括以下步骤：Include the following steps:

利用热仿真推算不同使用条件下，温度采样点和MOS管结温之间的关系表，Use thermal simulation to calculate the relationship table between the temperature sampling point and the junction temperature of the MOS tube under different operating conditions,

运行中根据实测或工作实际的损耗、电流、温度条件获取MOS管结温，During operation, the junction temperature of the MOS tube is obtained according to the actual measured or actual loss, current, and temperature conditions.

基于MOS管结温获取导通电阻Rdson，Obtain the on-resistance Rdson based on the junction temperature of the MOS tube,

采样获取对应的桥臂电压并与所述导通电阻计算获得电流。The corresponding bridge arm voltage is obtained by sampling, and the current is obtained by calculating with the on-resistance.

优选地，所述使用条件至少包括损耗、电流、温度条件，其中所述结温至少不同于温度检测器检测的温度数值。Preferably, the use conditions include at least loss, current, and temperature conditions, wherein the junction temperature is at least different from the temperature value detected by the temperature detector.

优选地，所述“运行中根据实测或工作实际的损耗、电流、温度条件获取MOS管结温”是基于查找表的方式实施的。Preferably, the "obtaining the junction temperature of the MOS tube according to the actual measured or actual loss, current, and temperature conditions during operation" is implemented based on a look-up table.

优选地，在桥臂下管驱动时，通过对所述桥臂下管进行采样获取对应的所述桥臂电压。Preferably, when the lower tube of the bridge arm is driven, the corresponding voltage of the bridge arm is obtained by sampling the lower tube of the bridge arm.

优选地，所述实际温度由设置在所述MOS管附近的温度传感器获取，其不同于所述结温。Preferably, the actual temperature is acquired by a temperature sensor disposed near the MOS transistor, which is different from the junction temperature.

优选地，所述“基于MOS管结温获取导通电阻Rdson”是通过MOS管结温与导通电阻的关系曲线来获取导通电阻Rdson的。Preferably, the "obtaining the on-resistance Rdson based on the junction temperature of the MOS tube" is to obtain the on-resistance Rdson through the relationship curve between the junction temperature of the MOS tube and the on-resistance.

优选地，所述桥臂电压是在桥臂下管常通时刻通过采样电流获取的。Preferably, the bridge arm voltage is obtained by sampling the current when the lower tube of the bridge arm is normally on.

优选地，所述结温与MOS管导通电阻Rdson的关系呈正相关变化。Preferably, the relationship between the junction temperature and the on-resistance Rdson of the MOS transistor changes in a positive correlation.

优选地，所述“采样获取对应的桥臂电压并与所述导通电阻计算获得电流”是通过欧姆定律公式计算的。Preferably, the "sampling to obtain the corresponding bridge arm voltage and calculating the current with the on-resistance" is calculated by using Ohm's law formula.

优选地，当实测或工作实际的损耗、电流、温度条件超出预先生成的关系表中记录的条件选择时，选择向外界报警和/或控制输出电流降低。Preferably, when the actual measured or actual loss, current, and temperature conditions exceed the condition selection recorded in the pre-generated relationship table, an alarm is selected to the outside world and/or the output current is controlled to decrease.

本发明优势在于：The advantages of the present invention are:

基于对MOS管结温与采样设备采集的MOS管工作环境温度的不同以及不同损耗、电流对MOS管结温带来的不同影响的考虑，利用热仿真对不同损耗、电流、温度下的MOS结温进行对应，并基于对应表获得当前使用情况下的结温，经过温度补偿后，电流采样值与实际电流值基本一致，相较于直接使用温度采样器的温度采样结果来作为MOS管内阻计算基础来说更加符合电流的真实值，消除了大量的误差，对后续的计算处理控制工作提供了很好的基础数值保障。Based on the difference between the junction temperature of the MOS tube and the working environment temperature of the MOS tube collected by the sampling device, and the different effects of different losses and currents on the junction temperature of the MOS tube, thermal simulation is used to analyze the MOS junction temperature under different losses, currents and temperatures. Corresponding, and based on the corresponding table to obtain the junction temperature under the current use condition, after temperature compensation, the current sampling value is basically the same as the actual current value, compared to directly using the temperature sampling result of the temperature sampler as the basis for calculating the internal resistance of the MOS tube It is more in line with the real value of the current, eliminates a large number of errors, and provides a good basic numerical guarantee for the subsequent calculation and control work.

附图说明Description of drawings

图1是本发明提供的一种优选实施方式的方案步骤图；Fig. 1 is a scheme step diagram of a preferred embodiment provided by the present invention;

图2是MOSFET内阻与温度特性示意图；Figure 2 is a schematic diagram of MOSFET internal resistance and temperature characteristics;

图3是利用本发明提供的方案补偿后的采样电流与常规方案采样电流的对比图。FIG. 3 is a comparison diagram of the sampled current after compensation by the solution provided by the present invention and the sampled current of the conventional solution.

具体实施方式Detailed ways

下面结合附图1进行详细说明。A detailed description will be given below in conjunction with FIG. 1 .

本发明提供一种基于MOS压降的新型电流采样方法，其针对的是采用MOS管压降电流计算方式，其中，在电流过大时，电阻的发热较为严重，影响整机效率。MOS管压降方式若不进行补偿，采样的精度经常难以得到保障。其精度随着温度变化而变差的原因是，由于MOSFET自身的温度特性导致的内阻变化，其中MOSFET是指金属-氧化物半导体场效应晶体管，是一种广泛使用在模拟电路和数字电路上的场效应晶体管。MOSFET自身内阻变化会导致压降变化，使得采样电流与实际电流出现较大的偏差，无法通过采样电流值实现正常的控制。根据压降测量电流的方式是基于I＝U/R公式获得的，理论上，在获知管的两端电压放大值后，将其分别除以管电阻既可以获知流过该管的电流值大小，在此，除了电压值是实际测量获得之外，管电阻应当是已知的固定值，但是在产生温度变化时，MOS管内阻将产生变化，也即电阻值不再是上述已知的固定值，而是产生了一定的偏离，因此利用其阻值计算的电流采样值会产生较大偏离。The present invention provides a new current sampling method based on MOS voltage drop, which is aimed at using the MOS tube voltage drop current calculation method, wherein when the current is too large, the heating of the resistor is serious, which affects the efficiency of the whole machine. If the MOS tube voltage drop method is not compensated, the sampling accuracy is often difficult to guarantee. The reason why its accuracy deteriorates with temperature changes is that the internal resistance changes due to the temperature characteristics of the MOSFET itself. field effect transistor. The change of the internal resistance of the MOSFET will lead to the change of the voltage drop, which makes the sampling current and the actual current have a large deviation, and the normal control cannot be realized by the sampling current value. The way to measure the current according to the voltage drop is obtained based on the formula I=U/R. In theory, after knowing the voltage amplification value at both ends of the tube, divide it by the tube resistance to know the current value flowing through the tube. , Here, in addition to the actual measurement of the voltage value, the tube resistance should be a known fixed value, but when the temperature changes, the internal resistance of the MOS tube will change, that is, the resistance value is no longer the above-mentioned known fixed value However, there is a certain deviation, so the current sampling value calculated by its resistance value will have a large deviation.

MOSFET在芯片设计中具有尺寸小，应用过程中具有功耗低、负载能力强以及反应速度快等众多优点。在电机控制器中，MOSFET作为开关在电路中用于过流点判断。MOSFET一般工作在非饱和区，即线性区，其中一个重要指标则是导通电阻R_dson。在理想状态下的导通电阻R_dson为零，但是在实际情况下不存在理想状态的情况。本发明通过MOS管结温与导通电阻之间的关系，得出推算的导通电阻。MOSFET has many advantages such as small size in chip design, low power consumption, strong load capacity and fast response speed in the application process. In the motor controller, the MOSFET is used as a switch in the circuit for overcurrent point judgment. MOSFET generally works in the non-saturation region, that is, the linear region, and one of the important indicators is the on-resistance R _dson . The on-resistance R _dson is zero in an ideal state, but there is no ideal state in a practical situation. The present invention obtains the estimated on-resistance through the relationship between the junction temperature of the MOS tube and the on-resistance.

本实施利用单向电机驱动器为例进行阐述，实际上本方法同样适用于三相交流变换器。The present embodiment is described by taking a unidirectional motor driver as an example, in fact, the method is also applicable to a three-phase AC converter.

PWM采用单极性的驱动方式，PWM为脉冲宽度调制，其是通过将有效的电信号分散成离散形式从而来降低电信号所传递的平均功率的一种方式，在连续的电流输出中，将电流按照通断的方式划分为等值输出的片段，通路时进行输出，断路时暂停输出，通断之间的时间间隔可以划分为时间片，将连续变化的电流做功按照等量替换的方式差分为数个等值输出的段落，并且通断的时间片长度可以变更，即输出宽度变更。不同于双极性驱动方式，单极性驱动电流采用四个晶体管来驱动步进电机的两组相位。PWM adopts a unipolar driving method, and PWM is a pulse width modulation, which is a way to reduce the average power transmitted by the electrical signal by dispersing the effective electrical signal into discrete forms. The current is divided into equal-value output segments according to the way of on-off. The output is performed when the circuit is on, and the output is suspended when the circuit is off. The time interval between on-off can be divided into time slices, and the continuously changing current work can be differentiated by equal replacement. For several paragraphs of equal value output, and the length of the on-off time slice can be changed, that is, the output width can be changed. Unlike the bipolar drive method, the unipolar drive current uses four transistors to drive the two sets of phases of the stepper motor.

在经过脉冲宽度调制后，电机驱动输出呈现分块式，在对应桥臂下管常通的时刻，通过采样电路，得到对应桥臂中点电压，由此利用欧姆定律公式，即I＝U/R公式可以反推得出此时流经桥臂的电流。然而实际过程中，如图2所示，MOS内阻随着MOS管结温升高而增大，即呈正相关关系，其中，结温是电子设备中半导体的实际工作温度，其通常比封装外壳的温度高。如果不考虑MOS管的结温因素，则采样得到的电流与实际偏差较大。本发明在基本不改变现有硬件方案的基础上采集桥臂中点电压，同时通过引入MOSFET的结温与损耗关系、结温与MOS内阻的关系以及结温与采样点温度的关系，形成对应的函数关系作为补偿公式，带入采样计算电流值中进行使用，实现在不同电流，不同温升的情况下对采样值的精确补偿，以保证电流采样的精度。优选地，所述MOSFET的结温与损耗关系、结温与MOS内阻的关系以及结温与采样点温度的关系，形成对应的函数关系作为补偿公式，可通过MCU实现。具体地，MCU通过键值型数据库建立多维数据的对应关系。将MOSFET的结温与损耗关系、结温与MOS内阻的关系以及结温与采样点温度的关系存储入键值型数据库的事实数据表中，通过以温度作为采样点，即键值，从中提出相应MOS管导通电阻。通过上述方法将MOSFET的结温与损耗关系、结温与MOS内阻的关系以及结温与采样点温度的关系一一对应，在进行数据查询时，只需在相应键值型数据库的维度数据表定位并输出或变更一条数据即可，无需对维度数据表进行全文计算。After the pulse width modulation, the motor drive output is divided into blocks. At the moment when the lower tube of the corresponding bridge arm is normally on, the midpoint voltage of the corresponding bridge arm is obtained through the sampling circuit, and the Ohm's law formula is used, that is, I=U/ The R formula can infer the current flowing through the bridge arm at this time. However, in the actual process, as shown in Figure 2, the internal resistance of the MOS increases with the increase of the junction temperature of the MOS tube, that is, there is a positive correlation. high temperature. If the junction temperature factor of the MOS tube is not considered, the sampled current deviates greatly from the actual one. The present invention collects the midpoint voltage of the bridge arm on the basis of basically not changing the existing hardware scheme, and simultaneously introduces the relationship between the junction temperature and loss of MOSFET, the relationship between junction temperature and MOS internal resistance, and the relationship between junction temperature and sampling point temperature, forming The corresponding functional relationship is used as a compensation formula to be used in the sampling and calculation of the current value to achieve accurate compensation of the sampling value under different currents and different temperature rises, so as to ensure the accuracy of current sampling. Preferably, the relationship between the junction temperature and the loss, the relationship between the junction temperature and the MOS internal resistance, and the relationship between the junction temperature and the sampling point temperature of the MOSFET form a corresponding functional relationship as a compensation formula, which can be realized by the MCU. Specifically, the MCU establishes the corresponding relationship of the multi-dimensional data through the key-value database. Store the relationship between the junction temperature and loss of MOSFET, the relationship between junction temperature and MOS internal resistance, and the relationship between junction temperature and sampling point temperature in the fact data table of the key-value database. The corresponding MOS transistor on-resistance is proposed. Through the above method, the relationship between the junction temperature and the loss of the MOSFET, the relationship between the junction temperature and the MOS internal resistance, and the relationship between the junction temperature and the sampling point temperature are in one-to-one correspondence. It is enough to locate and output or change a piece of data in the table, without the need to perform full-text calculation on the dimension data table.

在热仿真模型中搭建控制器模型和MOS管仿真模型，根据系统输入的损耗，电流，温度，可以得出MOS管结温与控制器采样点温度之间的关系表，由此关系表可以进一步推算各种工况下，MOS管内阻与采样点温度之间的关系。The controller model and the MOS tube simulation model are built in the thermal simulation model. According to the loss, current, and temperature of the system input, the relationship table between the junction temperature of the MOS tube and the temperature at the sampling point of the controller can be obtained. Calculate the relationship between the internal resistance of the MOS tube and the temperature of the sampling point under various working conditions.

本方案至少具有以下内容，通过MOSFET的Rdson采样桥臂中电压，根据采样点温度与结温关系(该关系是通过仿真确认并进行实验验证的)，形成函数关系公式对Rdson的变化进行补偿，输出最终经过补偿的计算电流值。This scheme has at least the following contents. The voltage in the bridge arm is sampled by the Rdson of the MOSFET, and according to the relationship between the temperature of the sampling point and the junction temperature (this relationship is confirmed by simulation and verified by experiments), a functional relationship formula is formed to compensate for the change of Rdson, The final compensated calculated current value is output.

将上述内容转化为如下步骤。Transform the above into the following steps.

S1、利用热仿真推算不同使用条件下，温度采样点和MOS管结温之间的关系表；S1. Use thermal simulation to calculate the relationship table between the temperature sampling point and the junction temperature of the MOS tube under different conditions of use;

所述使用条件至少包括损耗、电流、温度条件。The use conditions include at least loss, current, and temperature conditions.

S2、运行中根据实测或工作实际的损耗、电流、温度条件，按照查找表的方式获得MOS管结温，基于MOS管结温与导通电阻Rdson的关系曲线获取导通电阻Rdson。S2. According to the actual measured or working loss, current, and temperature conditions during operation, the junction temperature of the MOS tube is obtained by a look-up table, and the on-resistance Rdson is obtained based on the relationship curve between the junction temperature of the MOS tube and the on-resistance Rdson.

S3、在桥臂下管驱动时，采样获取对应的桥臂电压。S3. When the lower tube of the bridge arm is driven, the corresponding bridge arm voltage is obtained by sampling.

S4、基于获取的桥臂电压与所述导通电阻Rdson计算获取流经桥臂的电机电流。S4. Calculate and obtain the motor current flowing through the bridge arm based on the obtained bridge arm voltage and the on-resistance Rdson.

根据一种优选的实施方式，其中所述桥臂电压计算公式为：According to a preferred embodiment, the calculation formula of the bridge arm voltage is:

V_S＝I×(R_dson+线路寄生阻抗)V _S =I×(R _dson + line parasitic impedance)

其中，R_dson为MOSFET中的导通电阻，线路寄生阻抗为线路两点间的电阻。对于上述的线路寄生阻抗，其主要来源于内部线路和过孔，其中线路中的寄生阻抗是实际存在的，是不可避免的，是现如今生产工艺始终不能去除的难题。批量的产品在制作过程中会出现制作工艺以及器件自身差异的不同导致线路寄生阻抗的不同。Among them, R _dson is the on-resistance in the MOSFET, and the line parasitic impedance is the resistance between two points of the line. For the above-mentioned line parasitic impedance, it mainly comes from internal lines and vias, and the parasitic impedance in the line actually exists and is unavoidable, and it is a difficult problem that cannot be removed by the current production process. In the production process of batch products, the difference in the production process and the difference in the device itself will lead to the difference in the parasitic impedance of the line.

优选地，当实测或工作实际的损耗、电流、温度条件超出预先生成的关系表中记录的条件选择时，选择向外界报警和/或控制输出电流降低。Preferably, when the actual measured or actual loss, current, and temperature conditions exceed the condition selection recorded in the pre-generated relationship table, an alarm is selected to the outside world and/or the output current is controlled to decrease.

如图3所示，其为采用本发明进行补偿之后的电流采样结果与利用常规技术采样的电流结果的对比图，其中，常规方案采用温度采样设备采样的MOS管周围的温度直接替代MOS管结温计算。图中，线4为实际电流值，其反应电流的真实值；线2为补偿电流值，其为采用本发明提供的方案采样的电流值；线3为原始电流值，其为采用常规方案进行采样的电流值；线1的PCBT为温度采样器采集的温度数值。可以看出相较于常规方案，本方案获得的电流采样值在各个电流变化阶段均更加接近电流的真实结果，甚至在一些高位电流时，常规方案采样的电流随着MOS管温度升高而逐渐偏离实际电流，甚至在电流平台末期，其采样结果已经大量偏离真实值，从采样置信度来看已经完全处于不可采信的数据。而基于本方案采集电流在高位电流值仍然能够获得较高的跟随性，具有更好的检测准确度。As shown in FIG. 3, it is a comparison diagram of the current sampling result after compensation using the present invention and the current sampling result using the conventional technology, wherein the conventional solution uses the temperature around the MOS tube sampled by the temperature sampling device to directly replace the MOS tube junction temperature calculation. In the figure, line 4 is the actual current value, which is the real value of the reaction current; line 2 is the compensation current value, which is the current value sampled by the scheme provided by the present invention; The sampled current value; the PCBT of line 1 is the temperature value collected by the temperature sampler. It can be seen that compared with the conventional scheme, the current sampling value obtained by this scheme is closer to the real result of the current in each current change stage, and even at some high currents, the current sampled by the conventional scheme gradually increases with the temperature of the MOS tube. Deviating from the actual current, even at the end of the current platform, the sampling results have deviates from the real value by a large amount, which is completely unacceptable data from the perspective of sampling confidence. However, the acquisition current based on this scheme can still obtain higher follow-up performance at high current value, and has better detection accuracy.

根据一种优选的实施方式，上述方法的实现可通过一种计算终端进行。所述计算终端包括：一个或多个计算单元；以及与一个或多个计算单元相连的储存单元，储存单元用于储存指令，所述指令在被一个或多个计算单元执行时，执行上述方法。According to a preferred embodiment, the implementation of the above method can be performed by a computing terminal. The computing terminal includes: one or more computing units; and a storage unit connected to the one or more computing units, the storage unit is used for storing instructions, and the instructions execute the above method when executed by the one or more computing units .

计算单元可为MCU的不同型号，通过现场可编程门阵列FPGA(Field-ProgrammableGate Array)或复杂可编程逻辑器件CPLD(Complex Programmable Logic Device)。优选地，计算单元还可为通用中央处理器CPU(Central Processing Unit)、应用专用集成电路ASIC(Application Specific Integrated Circuit)、微处理器或者一个或多个集成电路等构件执行相关指令或程序以实现本发明的技术方案。本发明对计算单元采用的具体器件种类并不做限定，具体视实际情况而定。优选地，所述储存单元可采用只读存储器ROM(ReadOnly Memory)、随机存取存储器RAM(Random Access Memory)、静态存储设备、动态存储设备等形式实现。The computing unit can be a different type of MCU, through a field programmable gate array FPGA (Field-ProgrammableGate Array) or a complex programmable logic device CPLD (Complex Programmable Logic Device). Preferably, the computing unit can also be a general-purpose central processing unit (Central Processing Unit), an application specific integrated circuit (ASIC), a microprocessor, or one or more integrated circuits and other components to execute relevant instructions or programs to achieve Technical scheme of the present invention. The present invention does not limit the specific types of devices used in the computing unit, and it depends on the actual situation. Preferably, the storage unit may be implemented in the form of a read-only memory (ROM), a random access memory (RAM), a static storage device, a dynamic storage device, and the like.

根据一种优选的实施方式，储存单元还可用于故障事件的记录。记录的是MOS管最近若干次的故障发生。事件日志显示发生故障时的内阻、温度采样点情况、以及MOS管温升情况。上述信息可以通过连接至储存单元的数据端口来访问。通过上述方式给出故障可能产生的原因，以便于使用人员能够进一步完善MOS管存在的问题。According to a preferred embodiment, the storage unit can also be used for the recording of fault events. The record is that the MOS tube has failed several times recently. The event log shows the internal resistance, temperature sampling point, and MOS tube temperature rise when a fault occurs. The above information can be accessed through a data port connected to the storage unit. The possible causes of the failure are given in the above manner, so that the user can further improve the problems existing in the MOS transistor.

需要注意的是，上述构件仅示出针对本发明的具体实施例所需构件例如计算单元、储存单元，并不代表不包括计算终端实现正常运行的其余构件。It should be noted that the above-mentioned components only illustrate the components required for a specific embodiment of the present invention, such as a computing unit and a storage unit, and do not mean that the remaining components for the normal operation of the computing terminal are not included.

为了便于理解，将本发明一种基于MOS压降的新型电流采样方法的工作原理和使用方法进行论述。In order to facilitate understanding, the working principle and usage method of a novel current sampling method based on MOS voltage drop of the present invention will be discussed.

首先，本发明在现有硬件方案的基础上通过MOSFET的Rdson采集桥臂中点电压，同时通过采样点温度与结温的关系(通过仿真确认关系，并进行实验验证)，即引入MOSFET的结温与损耗关系、结温与MOS内阻的关系以及结温与采样点温度的关系，形成对应的函数关系作为补偿公式，带入采样计算电流值中进行使用，从而对Rdson的变化进行补偿，实现在不同电流、不同温升的情况下对采样值进行精确补偿，以保证电流采样的精度。最终输出经过补偿的计算电流值。First of all, the present invention collects the midpoint voltage of the bridge arm through the Rdson of the MOSFET on the basis of the existing hardware solution, and simultaneously uses the relationship between the temperature of the sampling point and the junction temperature (the relationship is confirmed by simulation and verified by experiments), that is, the junction of the MOSFET is introduced. The relationship between temperature and loss, the relationship between junction temperature and MOS internal resistance, and the relationship between junction temperature and sampling point temperature, form the corresponding functional relationship as a compensation formula, which is brought into the sampling calculation current value for use, thereby compensating for the change of Rdson, Accurately compensate the sampling value under different currents and different temperature rises to ensure the accuracy of current sampling. The final output is the compensated calculated current value.

通过上述方式，本发明解决在当前实际应用中出现的由于温度升高，利用MOS管压降电流采样不准的问题。In the above manner, the present invention solves the problem of inaccurate current sampling by using the voltage drop of the MOS tube due to the temperature rise in current practical applications.

在全文中，“优选地”所引导的特征仅为一种可选方式，不应理解为必须设置，故此申请人保留随时放弃或删除相关优选特征之权利。In the whole text, the features introduced by "preferably" are only an optional way, and should not be construed as a mandatory setting, so the applicant reserves the right to abandon or delete the relevant preferred features at any time.

需要注意的是，上述具体实施例是示例性的，本领域技术人员可以在本发明公开内容的启发下想出各种解决方案，而这些解决方案也都属于本发明的公开范围并落入本发明的保护范围之内。本领域技术人员应该明白，本发明说明书及其附图均为说明性而并非构成对权利要求的限制。本发明的保护范围由权利要求及其等同物限定。本发明说明书包含多项发明构思，诸如“优选地”、“根据一个优选实施方式”或“可选地”均表示相应段落公开了一个独立的构思，申请人保留根据每项发明构思提出分案申请的权利。It should be noted that the above-mentioned specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the scope of the present invention. within the scope of protection of the invention. It should be understood by those skilled in the art that the description of the present invention and the accompanying drawings are illustrative rather than limiting to the claims. The protection scope of the present invention is defined by the claims and their equivalents. The description of the present invention contains multiple inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally" all indicate that the corresponding paragraph discloses a separate concept, and the applicant reserves the right to propose divisions according to each inventive concept the right to apply.