阅读说明：本技术 基于端电压过零点和状态寄存器信号存储的位置检测方法 (Position detection method based on terminal voltage zero crossing point and state register signal storage ) 是由 赵冬冬 王西坡 谭博 皇甫宜耿 于 2019-10-16 设计创作，主要内容包括：本发明涉及一种基于端电压过零点和状态寄存器信号存储的位置检测方法,针对换相续流干扰信号的规律性,考虑对干扰信号加以利用,而不是对其进行滤波处理。采用寄存器记录端电压过零点信号的状态序列,根据前两个的过零点状态来判断当前的过零点信号是否是正确的过零点信号。与现有技术相比,提出的基于状态寄存器存储部分过零点,根据前两个端电压过零点来判断当前过零点有效与否的方法比较简单,相比于传统的无位置方法不需要增加额外的硬件电路,占用的计算机资源也更少。(The invention relates to a position detection method based on terminal voltage zero crossing points and state register signal storage, which considers the utilization of interference signals instead of filtering the interference signals according to the regularity of commutation follow current interference signals. And judging whether the current zero-crossing point signal is a correct zero-crossing point signal or not according to the first two zero-crossing point states by adopting a state sequence of terminal voltage zero-crossing point signals recorded by a register. Compared with the prior art, the method for judging whether the current zero-crossing point is effective or not according to the zero-crossing points of the front two terminal voltages is simple based on the zero-crossing point of the storage part of the state register, and compared with the traditional position-free method, the method does not need to add an additional hardware circuit and occupies less computer resources.)

1. A position detection method based on terminal voltage zero crossing points and state register signal storage is characterized by comprising the following steps:

step 1: the register records a three-phase zero-crossing signal sequence, and the current zero-crossing point and the previous two zero-crossing points are put into a state register; wherein: three-bit numbers of counter potential zero-crossing points in the state register respectively represent the states of the counter potential of the A, B, C three-phase winding from left to right, when a certain counter potential voltage is greater than zero, the counter potential voltage is marked as 1, and if the counter potential voltage is less than or equal to zero, the counter potential voltage is marked as zero; three-digit numbers of the terminal voltage zero crossing points respectively represent states of A, B, C three-phase terminal voltages from left to right, when the voltage of a certain phase terminal is greater than half of the bus voltage, the state is marked as 1, and if the voltage of the certain phase terminal is less than or equal to half of the bus voltage, the state is marked as zero;

step 2: judging whether the current end voltage zero crossing point signal is effective or not according to the previous two end voltage zero crossing point signals

1. Current terminal voltage zero crossing state 101: if the first two states are 101 and 001, the actual zero crossing point is 101, otherwise, the zero crossing point is kept unchanged;

2. current terminal voltage zero crossing state 100: if the first two states are 100 and 101, the actual zero crossing point is 100, otherwise, the zero crossing point is kept unchanged;

3. current terminal voltage zero crossing state 110: if the first two states are 110 and 100, the actual zero crossing point is 110, otherwise, the zero crossing point is kept unchanged;

4. current terminal voltage zero crossing state 010: if the first two states are 010 and 110, the actual zero crossing point is 010, otherwise, the zero crossing point is kept unchanged;

5. current terminal voltage zero crossing state 011: if the first two states are 011 and 010, the actual zero crossing point is 011, otherwise, the zero crossing point is kept unchanged;

6. current terminal voltage zero crossing state 001: if the first two states are 001 and 011, the actual zero crossing point is 001, otherwise, the zero crossing point is kept unchanged.

Technical Field

The invention belongs to a position sensorless method of a brushless direct current motor, and relates to a position detection method based on terminal voltage zero crossing points and state register signal storage.

Background

With the shortage of global energy supply and the increasingly prominent environmental problems, people strive to find new energy sources to replace the traditional fossil energy sources. A fuel cell is a cell that is externally supplied with an oxidant, which may be oxygen in air, pure oxygen, and a reductant, which is usually hydrogen, methane, coal gas, etc., which react in a fuel cell stack to generate water and carbon dioxide. The product of the hydrogen fuel cell is only water, has the characteristics of high efficiency and zero pollution, and is widely researched in the fields of automobiles and unmanned aerial vehicles in recent years.

When the fuel cell unmanned aerial vehicle flies at high altitude, the air compressor is needed to be pressurized to provide enough oxygen because the air is thin. In order to reduce the volume and the weight of the air compressor, the ultra-high speed brushless direct current motor is required to be used for driving (the maximum rotating speed is known to be 100 ten thousand rpm), and the position sensor can be caused to be invalid in severe environments such as low temperature and humidity, so that the research on the position-free sensor of the ultra-high speed brushless direct current motor is significant.

The back emf zero crossing point detection method is the most commonly used position-sensorless method at present, and because the armature winding presents an inductive property, a follow current phenomenon can be generated during phase commutation, and then interference is generated on a zero crossing point signal. The interference signal can be suppressed by adding low-pass filtering, but a certain signal delay is brought, and the delay can cause a large position error at high speed, so that the motor is out of step. In addition, a filter with fixed delay time is adopted, and a zero crossing point without filter delay can be obtained through compensation, but the working speed range of the ultra-high-speed brushless direct current motor is wide, and different fixed filter time is needed in low-speed, high-speed and ultra-high-speed stages. Because the speed of the motor fluctuates, delay and compensation are not corresponding frequently when switching is carried out at different speed stages, larger position error is caused, and even the motor is out of step and stops rotating.

The document Jiang Q, Bi C, Huang R.A new phase-delay-free method to detect back EMF zero-cross points for sensor control of free motors [ J ]. IEEEtransactions on Magnetics,2005,41(7): 2287) 2294. the zero-crossing sequence is also used to judge the effective zero-crossing, but it needs complicated logic judgment and theoretical derivation and corresponding hardware circuit, and also occupies a lot of resources of the computer.

Disclosure of Invention

Technical problem to be solved

In order to avoid the defects of the prior art, the invention provides a position detection method based on terminal voltage zero crossing points and state register signal storage, which is a position-free method suitable for any speed range is found based on back emf zero crossing point detection.

Technical scheme

A position detection method based on terminal voltage zero crossing points and state register signal storage is characterized by comprising the following steps:

step 1: the register records a three-phase zero-crossing signal sequence, and the current zero-crossing point and the previous two zero-crossing points are put into a state register; wherein: three-bit numbers of counter potential zero-crossing points in the state register respectively represent the states of the counter potential of the A, B, C three-phase winding from left to right, when a certain counter potential voltage is greater than zero, the counter potential voltage is marked as 1, and if the counter potential voltage is less than or equal to zero, the counter potential voltage is marked as zero; three-digit numbers of the terminal voltage zero crossing points respectively represent states of A, B, C three-phase terminal voltages from left to right, when the voltage of a certain phase terminal is greater than half of the bus voltage, the state is marked as 1, and if the voltage of the certain phase terminal is less than or equal to half of the bus voltage, the state is marked as zero;

step 2: judging whether the current end voltage zero crossing point signal is effective or not according to the previous two end voltage zero crossing point signals

1. Current terminal voltage zero crossing state 101: if the first two states are 101 and 001, the actual zero crossing point is 101, otherwise, the zero crossing point is kept unchanged;

2. current terminal voltage zero crossing state 100: if the first two states are 100 and 101, the actual zero crossing point is 100, otherwise, the zero crossing point is kept unchanged;

3. current terminal voltage zero crossing state 110: if the first two states are 110 and 100, the actual zero crossing point is 110, otherwise, the zero crossing point is kept unchanged;

4. current terminal voltage zero crossing state 010: if the first two states are 010 and 110, the actual zero crossing point is 010, otherwise, the zero crossing point is kept unchanged;

5. current terminal voltage zero crossing state 011: if the first two states are 011 and 010, the actual zero crossing point is 011, otherwise, the zero crossing point is kept unchanged;

6. current terminal voltage zero crossing state 001: if the first two states are 001 and 011, the actual zero crossing point is 001, otherwise, the zero crossing point is kept unchanged.

Advantageous effects

According to the position detection method based on the terminal voltage zero crossing point and the state register signal storage, aiming at the regularity of the commutation follow current interference signal, the interference signal is considered to be utilized instead of being subjected to filtering processing. And judging whether the current zero-crossing point signal is a correct zero-crossing point signal or not according to the first two zero-crossing point states by adopting a state sequence of terminal voltage zero-crossing point signals recorded by a register. Compared with the prior art, the method for judging whether the current zero-crossing point is effective or not according to the zero-crossing points of the front two terminal voltages is simple based on the zero-crossing point of the storage part of the state register, and compared with the traditional position-free method, the method does not need to add an additional hardware circuit and occupies less computer resources.

Compared with the prior art, the invention has the following characteristics:

1. no filtering of the zero crossing signal is required.

2. The method is independent of speed and is suitable for any speed range of the ultra-high-speed brushless direct current motor.

3. Compared with the prior art, the method is simpler and occupies fewer computer resources.

4. The invention provides a technical scheme different from that in the literature, which can reach the level of the prior art and can realize the operation of a brushless DC motor without a position within the full speed range.

Drawings

FIG. 1: zero crossing with follow current interference signal

FIG. 2: flow chart for judging zero crossing point signal

FIG. 3: simulation result

FIG. 4: simulation result

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

FIG. 1 is a three-phase zero-crossing signal containing a commutation freewheel disturbance signal. And recording the state of the three-phase zero-crossing point signal, and judging whether the current zero-crossing point signal is a correct zero-crossing point through the first two zero-crossing point signals.

The method comprises the following steps: the register records a three-phase zero-crossing signal sequence, and the current zero-crossing point and the previous two zero-crossing points are put into a state register.

Three-digit numbers of counter potential zero-crossing points respectively represent states of counter potentials of A, B, C three-phase windings from left to right, if the voltage of the A counter potential is larger than zero, the corresponding state is marked as 1, and if the voltage of the A counter potential is smaller than or equal to zero, the corresponding state is marked as zero, and the same principle is adopted in B, C. Three-digit numbers of terminal voltage zero-crossing points respectively represent states of A, B, C three-phase terminal voltages from left to right, if the voltage of the A-phase terminal is greater than half of the bus voltage, the corresponding state is marked as 1, and if the voltage of the A-phase terminal is less than or equal to half of the bus voltage, the corresponding state is marked as zero, and B, C is the same. Since the back emf is located inside the motor, the state of the back emf cannot be measured generally, and the back emf zero crossing point is mostly judged by measuring the state of terminal voltage at present. However, since the motor windings are inductive, freewheeling occurs at each phase winding turn-off, which causes the terminal voltage zero-crossing to become inconsistent with the back-emf zero-crossing, which represents the actual position information of the motor rotor. The sequence of zero crossings in table 1 may be listed in conjunction with fig. 1.

Step two: and judging whether the current terminal voltage zero-crossing point signal is effective or not according to the previous two terminal voltage zero-crossing point signals. Judging according to the zero-crossing sequence in table 1, assuming that the current zero-crossing signal is 100, if the first two zero-crossing signals are 100 and 101, the current zero-crossing signal 100 is the correct zero-crossing signal, otherwise, the current zero-crossing signal 100 is considered to be an interference signal generated by the follow current, and the previous zero-crossing signal is kept unchanged. The judgment flow chart is shown in fig. 2.

1. TABLE 1 zero-crossing sequence determination

The brushless direct current motor has six working states in one working period, namely AB phase conduction, AC phase conduction, BC phase conduction, BA phase conduction, CA phase conduction and CB phase conduction, the actual zero crossing points are 101, 001, 011, 010, 110 and 100 respectively, the correct zero crossing points are obtained by the proposed method for judging whether the terminal voltage zero crossing points are correct, the zero crossing points are delayed by 30 degrees of electrical angle, and accurate position information can be obtained, wherein the specific judging method comprises the following steps:

[1] current terminal voltage zero crossing state 101: if the first two states are 101 and 001, the actual zero crossing point is 101, otherwise, the zero crossing point is kept unchanged;

[2] current terminal voltage zero crossing state 100: if the first two states are 100 and 101, the actual zero crossing point is 100, otherwise, the zero crossing point is kept unchanged;

[3] current terminal voltage zero crossing state 110: if the first two states are 110 and 010, the actual zero crossing point is 110, otherwise, the zero crossing point is kept unchanged;

[4] current terminal voltage zero crossing state 010: if the first two states are 010 and 110, the actual zero crossing point is 010, otherwise, the zero crossing point is kept unchanged;

[5] current terminal voltage zero crossing state 011: if the first two states are 011 and 010, the actual zero crossing point is 011, otherwise, the zero crossing point is kept unchanged;

[6] current terminal voltage zero crossing state 001: if the first two states are 001 and 011, the actual zero crossing point is 001, otherwise, the zero crossing point is kept unchanged;

then, modeling simulation is carried out on the judging method provided by the invention, and fig. 4 shows a simulation result. In fig. 4, the dashed line represents actual hall position information, the solid line represents position information obtained by using the proposed determination method, the motor is started by the external synchronization method at 0.2s, and the two completely overlap after 0.225s, which illustrates the accuracy of the method. In fig. 4, the solid line is the actual speed, the dotted line is the closed-loop reference speed, the dotted line is the switching mark from the no-position starting to the no-position running, and the speed is up to 30 ten thousand rpm, so that the method is suitable for the ultra-high speed brushless direct current motor.