Calibration system of Hall current sensor

Abstract

The invention discloses a calibration system for a Hall current sensor, and relates to the technical field of electrical equipment, and the system comprises a constant current source which is used for outputting current; the switch is used for controlling the three-phase relay to be switched on or switched off; the lower computer is used for reading the current value of the phase collected by the Hall current sensor when any phase of the three-phase relay is conducted; and the upper computer is used for controlling the switch and the constant current source, reading the acquired current value from the lower computer, and calculating the current verification coefficient of the phase according to the current value and the current output by the constant current source. The calibration system can effectively improve the calibration efficiency and accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of electrical equipment, and in particular to a calibration system for a Hall current sensor. Background Art

[0002] Hall current sensors have many advantages such as wide measurement range and fast response speed. They are widely used in various fields such as variable frequency speed regulation devices, inverter devices, UPS power supplies, electrolytic plating, CNC machine tools, and microcomputer monitoring systems. For the calibration of Hall current sensors, the existing solutions mainly include:

[0003] Solution 1: During calibration, the supply voltage value is measured first, then the measured voltage value is converted according to the supply voltage value, and then calibration is performed according to the converted voltage value. Since two voltage value measurements and voltage conversions are required, the calibration efficiency is low. During calibration, the nonlinear error of the ADC and the error of the ADC / reference voltage are superimposed, resulting in low calibration accuracy.

[0004] Solution 2: Use a high-precision controllable low dropout regulator (LDO) as the power supply for the programmable linear Hall current sensor, a high-precision, low-noise reference voltage chip as the reference for the ADC, and a high-precision successive approximation ADC as the measurement chip. In this calibration solution, in order to ensure the test accuracy, the measurement system must be adjusted (hardware + software), resulting in low calibration efficiency.

[0005] Therefore, how to calibrate the Hall current sensor efficiently and accurately has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] The purpose of this application is to provide a calibration system for a Hall current sensor, which can effectively improve the calibration efficiency and accuracy.

[0007] In order to solve the above technical problems, the present application provides a calibration system for a Hall current sensor, comprising:

[0008] Constant current source, used for outputting current;

[0009] Switch, used to control the three-phase relay to be turned on or off;

[0010] The lower computer is used to read the current value of any phase collected by the Hall current sensor when any phase of the three-phase relay is turned on;

[0011] The upper computer is used to control the switch and the constant current source, read the collected current value from the lower computer, and calculate the current calibration coefficient of the phase according to the current value and the current output by the constant current source.

[0012] Optionally, the switch includes:

[0013] U phase contactor, V phase contactor and W phase contactor; when the U phase contactor is closed, the U phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the U phase; when the V phase contactor is closed, the V phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the V phase; when the W phase contactor is closed, the W phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the W phase.

[0014] Optionally, the host computer is specifically used for:

[0015] The ratio of the current output by the constant current source to the current value is calculated to obtain the current calibration coefficient.

[0016] Optionally, the host computer is also used for:

[0017] Determining whether the calculated current calibration coefficient is correct;

[0018] If the current calibration coefficient is incorrect, the calibration process ends.

[0019] Optionally, the host computer is specifically used for:

[0020] The current output by the constant current source is kept unchanged, and the collected current value is read from the lower computer again, and whether the current verification coefficient is correct is determined based on the current value.

[0021] Optionally, the host computer is specifically used for:

[0022] The constant current source is controlled to change the magnitude of the current output by the constant current source, and after the constant current source changes the magnitude of the current output by the constant current source, the collected current value is read again from the lower computer, and whether the current verification coefficient is correct is determined based on the current value.

[0023] Optionally, the lower computer is also used for:

[0024] Read the current sampling value of the DC bus acquired by the Hall current sensor.

[0025] Optionally, the host computer is also used for:

[0026] The current sampling value of the DC bus is read from the lower computer, and the current calibration coefficient of the DC bus is calculated according to the current sampling value of the DC bus and the current output by the constant current source.

[0027] Optionally, the host computer is also used for:

[0028] Before calculating and obtaining the current verification coefficient of the phase and the current verification coefficient of the DC bus, the current verification coefficient of each phase and the current verification coefficient of the DC bus are set to 100%.

[0029] Optionally, the host computer is also used for:

[0030] The calculated current verification coefficient of the phase and the current verification coefficient of the DC bus are written into a cache.

[0031] Optionally, the lower computer communicates with the upper computer via a CAN bus.

[0032] Optionally, the host computer communicates with the constant current source via a CAN bus.

[0033] Optionally, the lower computer is a DSP processor.

[0034] Optionally, also include:

[0035] A radiator is used to dissipate heat from the calibration system.

[0036] Optionally, the heat dissipation unit is a water flow radiator.

[0037] The calibration system of the Hall current sensor provided in the present application includes: a constant current source for outputting current; a switch for controlling the on or off of a three-phase relay; a lower computer for reading the current value of the phase collected by the Hall current sensor when any phase of the three-phase relay is turned on; and an upper computer for controlling the switch and the constant current source, reading the collected current value from the lower computer, and calculating the current calibration coefficient of the phase based on the current value and the current output by the constant current source.

[0038] It can be seen that the calibration system of the Hall current sensor provided by the present application outputs current from a constant current source, and realizes automatic calibration with the cooperation of the upper computer and the lower computer, without the need for manual operation by the operator, which can greatly improve the calibration efficiency, and has fast response speed and high reliability. In addition, the calibration system can perfectly adapt to the planar current sensor, meet the needs of separate calibration of the planar current sensor, and can effectively improve the calibration efficiency of the planar current sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the prior art and the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1A schematic diagram of a calibration system for a Hall current sensor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The core of this application is to provide a calibration system for a Hall current sensor, which can effectively improve the calibration efficiency and accuracy.

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] Please refer to Figure 1 , Figure 1 A schematic diagram of a calibration system for a Hall current sensor provided in an embodiment of the present application, with reference to Figure 1 As shown, the calibration system mainly includes:

[0044] A constant current source 101, used for outputting current;

[0045] Switch 102, used to control the three-phase relay to be turned on or off;

[0046] The lower computer 103 is used to read the current value of any phase of the three-phase relay collected by the Hall current sensor when the phase is turned on;

[0047] The upper computer 104 is used to control the switch 102 and the constant current source 101 , read the collected current value from the lower computer 103 , and calculate the current calibration coefficient of the phase according to the current value and the current output by the constant current source 101 .

[0048] The constant current source 101 is used to output current. Whether the constant current source 101 outputs current and the magnitude of the current output by the constant current source 101 are controlled by the host computer 104. In some embodiments, the constant current source 101 communicates with the host computer 104 via a CAN bus. The host computer 104 controls the constant current source 101 via the CAN bus.

[0049] The switch 102 is used to control the three-phase relay to be turned on or off. When a phase of the three-phase relay is turned on, current flows through the phase, and the Hall current sensor can collect the current of the phase.

[0050] In some embodiments, switch 102 includes: a U-phase contactor, a V-phase contactor, and a W-phase contactor; when the U-phase contactor is closed, the U-phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the U-phase; when the V-phase contactor is closed, the V-phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the V-phase; when the W-phase contactor is closed, the W-phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the W-phase.

[0051] like Figure 1 As shown, K1 is the U-phase contactor, K2 is the V-phase contactor, and K3 is the W-phase contactor. When the U-phase contactor is closed, the U-phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the U-phase; when the V-phase contactor is closed, the V-phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the V-phase; when the W-phase contactor is closed, the W-phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the W-phase.

[0052] The lower computer 103 is responsible for reading the current value collected by the Hall current sensor and communicating with the upper computer 104. The lower computer 103 also stores a flag (e.g., a zero drift calibration completion flag, a zero drift calibration prohibition flag) and a current calibration coefficient. In some embodiments, the lower computer 103 may be a DSP processor. In some embodiments, the lower computer 103 and the upper computer 104 may communicate via a CAN bus.

[0053] The host computer 104 reads the collected current value from the lower computer 103, and calculates the current calibration coefficient based on the collected current value and the current output by the constant current source 101. When the U-phase contactor is closed, the Hall current sensor collects the current value of the U-phase at this time, and the host computer 104 calculates the current calibration coefficient of the U-phase based on the collected current value of the U-phase and the current output by the sampled constant current source 101. When the V-phase contactor is closed, the Hall current sensor collects the current value of the V-phase at this time, and the host computer 104 calculates the current calibration coefficient of the V-phase based on the collected current value of the V-phase and the current output by the sampled constant current source 101. When the W-phase contactor is closed, the Hall current sensor collects the current value of the W-phase at this time, and the host computer 104 calculates the current calibration coefficient of the W-phase based on the collected current value of the W-phase and the current output by the sampled constant current source 101.

[0054] Figure 1 in,i u Indicates the current value of the collected U phase, i v Indicates the current value of the collected v phase, i w represents the collected current value of the w phase, idc is the collected current value of the DC bus, and Is is the current output by the constant current source 101 sampled by the host computer 104.

[0055] In some embodiments, the host computer 104 is specifically used for:

[0056] The ratio of the current output by the constant current source 101 to the current value is calculated to obtain the current verification coefficient of the phase.

[0057] In this embodiment, the host computer 104 calculates the current verification coefficient by calculating the ratio of the sampled current output by the constant current source 101 to the collected current value of the phase.

[0058] For example, the current verification coefficient of the U phase is equal to the ratio of the sampled current output by the constant current source 101 to the collected current value of the U phase.

[0059] In some embodiments, the host computer 104 is further used for:

[0060] Determining whether the calculated current calibration coefficient is correct;

[0061] If the current calibration coefficient is incorrect, the calibration process ends.

[0062] The method for judging whether the calculated current verification coefficient is correct may be:

[0063] The current output by the constant current source 101 is kept unchanged, and the collected current value is read from the lower computer 103 again. According to the current value, it is determined whether the current verification coefficient is correct.

[0064] For example, when the constant current source 101 outputs a current of 450A, after the current verification coefficient of the U phase is calculated, the constant current output current is maintained at 450A. At this time, the Hall current sensor samples the current value of the U phase again, and the upper computer 104 determines whether the current verification coefficient of the U phase calculated previously is correct based on the current value of the U phase sampled at this time.

[0065] The method of judging whether the U-phase current verification coefficient calculated before is correct according to the current value of the U-phase collected at this time can be:

[0066] The U-phase current value collected at this time is compensated according to the previously calculated U-phase current verification coefficient, and the current value output by the constant current source 101 is calculated. If the calculated current value output by the constant current source 101 is equal to the actual current output by the constant current source 101 or the deviation between the two is within the allowable deviation range, it is determined that the calculated U-phase current verification coefficient is correct.

[0067] The current value of the U-phase current collected at this time is calculated and compensated according to the previously calculated U-phase current verification coefficient, and the current value output by the constant current source 101 is calculated as follows: u =[I b *(Uad -1.5)-I0]*I k ; Among them, I u is the U phase current, I b is the current sampling coefficient, U ad is the AD port sampling voltage, 1.5 is the reference voltage (the busbar Hall reference value is 0, the AC Hall reference value may be 1.667, which can be confirmed according to the hardware), and I0 is the zero drift current.

[0068] The method of judging whether the U-phase current verification coefficient calculated previously is correct according to the current value of the U-phase collected at this time and the current output by the constant current source 101 sampled by the host computer 104 at this time can also be: a new U-phase current verification coefficient is calculated again according to the current value of the U-phase collected at this time and the current output by the constant current source 101 sampled by the host computer 104 at this time. If the new U-phase current verification coefficient is equal to the previously calculated U-phase current verification coefficient or the deviation between the two is within the allowable deviation range, it is determined that the previously calculated U-phase current verification coefficient is correct.

[0069] The above method of judging whether the U-phase current verification coefficient is correct is also applicable to the V-phase current verification coefficient and the W-phase current verification coefficient.

[0070] In addition, the method for judging whether the calculated current verification coefficient is correct may be:

[0071] The constant current source 101 is controlled to change the magnitude of the current output by the constant current source 101 , and after the constant current source 101 changes the magnitude of the current output by the constant current source 101 , the collected current value is read again from the lower computer 103 , and whether the current verification coefficient is correct is determined based on the current value.

[0072] After calculating the current verification coefficient of a certain phase, the upper computer 104 can increase or decrease the current output by the constant current source 101. After the constant current source 101 increases or decreases the output current, the Hall current sensor collects the current again, and the lower computer 103 reads the current value collected by the Hall current sensor at this time. The upper computer 104 determines whether the current verification coefficient of the phase calculated previously is correct based on the current value collected at this time.

[0073] For example, when the constant current source 101 outputs a current of 450A, after calculating the current verification coefficient of the U phase, the constant current output current is reduced to 225A. At this time, the Hall current sensor samples the current value of the U phase again. The upper computer 104 determines whether the current verification coefficient of the U phase calculated previously is correct based on the current value of the U phase sampled at this time.

[0074] The method of determining whether the current value of the U-phase collected at this time and the previously calculated U-phase current verification coefficient is correct can refer to the above embodiment and will not be repeated here.

[0075] If the current verification coefficient of any phase is incorrect, the host computer 104 may end the verification process.

[0076] In some embodiments, the lower computer 103 is also used for:

[0077] Read the current sampling value of the DC bus acquired by the Hall current sensor.

[0078] The host computer 104 is also used for:

[0079] The current sampling value of the DC bus is read from the lower computer 103 , and the current calibration coefficient of the DC bus is calculated according to the current sampling value of the DC bus and the current output by the constant current source 101 .

[0080] The current calibration coefficient of the DC bus can be obtained by calculating the ratio of the current output by the constant current source 101 and the current sampling value of the DC bus.

[0081] In some embodiments, the host computer 104 is further used for:

[0082] Before calculating the current verification coefficient of the phase and the current verification coefficient of the DC bus, the current verification coefficient of each phase and the current verification coefficient of the DC bus are set to 100%. And after calculating the current verification coefficient of a phase and the current verification coefficient of the DC bus, the calculated current verification coefficient of the phase and the current verification coefficient of the DC bus are written into the cache.

[0083] In this embodiment, before calibrating the Hall current sensor and obtaining the current verification coefficient, the current verification systems of the U-phase current, the V-phase current, and the W-phase current are all set to 100% and stored in the cache buffer. After calculating the current verification coefficient of a phase and the current verification coefficient of the DC bus, the calculated current verification coefficient of the phase and the current verification coefficient of the DC bus are written into the cache.

[0084] In some embodiments, the calibration system further comprises:

[0085] A radiator is used to dissipate heat from the calibration system.

[0086] The heat dissipation unit may be a water flow radiator. When performing preliminary preparations before calibrating the Hall current sensor, water is passed through the radiator. The water flow rate may be not less than 10 L / min.

[0087] Based on the calibration system of the Hall current sensor provided in the above embodiment, a specific calibration implementation process is provided below:

[0088] Step 1: Carry out preliminary preparation work such as wiring and water supply.

[0089] Step 2: The upper computer 104 confirms that the output current of the constant current source 101 is zero, disconnects all switches 102, and sends a communication mode flag to the lower computer 103, so that the lower computer 103 enters the communication mode.

[0090] Step 3: The lower computer 103 performs a zero drift check, and after completing the zero drift check, sets a zero drift check completion flag to 1 and stores it in a cache buffer.

[0091] Step 4: The lower computer 103 prohibits zero drift detection, sets the zero drift check prohibition flag to 1, and stores it in the cache buffer.

[0092] Step 5: The host computer 104 writes 100.0% to the DC bus current verification coefficient, the U-phase current verification coefficient, the V-phase current verification coefficient, and the W-phase current verification coefficient respectively, and stores them in the cache buffer.

[0093] Step 6: The lower computer 103 reads the zero drift check completion flag to confirm that the zero drift check is completed.

[0094] Step 7: The lower computer 103 reads the zero drift check prohibition flag to confirm that the zero drift detection has been prohibited.

[0095] Step 8, the host computer 104 reads the DC bus current verification coefficient, the U phase current verification coefficient, the V phase current verification coefficient, and the W phase current verification coefficient, and confirms that the DC bus current verification coefficient, the U phase current verification coefficient, the V phase current verification coefficient, and the W phase current verification coefficient are all 100.0%.

[0096] Step 9: The host computer 104 closes the U-phase contactor K1, reads the current value of the U-phase, and confirms that the current value is zero.

[0097] Step 10: The host computer 104 controls the constant current source 101 to output a current of 450A.

[0098] Step 11: The upper computer 104 reads the sampling value of the U phase from the lower computer 103.

[0099] Step 12: The host computer 104 samples the current value output by the constant current source 101.

[0100] Step 13, the upper computer 104 calculates the U-phase current verification coefficient according to the current value of the constant current source 101 obtained by sampling and the current value read from the lower computer 103, writes the U-phase current verification coefficient, and stores it in the cache buffer.

[0101] Step 14: After writing the U-phase current verification coefficient, the host computer 104 reads the current sampling value of the U-phase again to confirm whether the verification is correct.

[0102] Step 15: The host computer 104 reduces the current output by the constant current source 101, and reads the sampling value of the U phase again when the constant current source 101 outputs currents of 225A and 20A to confirm whether the calibration coefficient is correct.

[0103] Step 16, the host computer 104 stops the constant current source 101 from outputting current. If the U-phase current verification is confirmed to be correct, the U-phase contactor K1 is disconnected, and the V-phase and W-phase Hall detection is performed (the V-phase and W-phase Hall detection are the same as steps 9 to 16). If the U-phase current verification fails, the verification is exited.

[0104] Step 17: The three-phase current verification is completed, that is, the entire verification process is completed. Among them, the DC bus current verification can be completed synchronously during the U phase detection.

[0105] After the current calibration coefficient is obtained through calibration, compensation can be performed based on the current calibration coefficient during current sampling, thereby effectively improving the sampling accuracy.

[0106] The calibration system of the Hall current sensor provided in the present application outputs current from a constant current source, and realizes automatic calibration with the cooperation of a host computer and a slave computer, without the need for manual operation by an operator, which can greatly improve the calibration efficiency, and has fast response speed and high reliability. In addition, the calibration system can perfectly adapt to the planar current sensor, meet the needs of separate calibration of the planar current sensor, and can effectively improve the calibration efficiency of the planar current sensor.

[0107] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0108] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0109] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0110] The calibration system of the Hall current sensor provided by the present application is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A calibration system for a Hall current sensor, characterized in that: include: Constant current source, used for outputting current; Switch, used to control the three-phase relay to be turned on or off; The lower computer is used to read the current value of any phase collected by the Hall current sensor when any phase of the three-phase relay is turned on; The upper computer is used to control the switch and the constant current source, read the collected current value from the lower computer, and calculate the current calibration coefficient of the phase according to the current value and the current output by the constant current source.

2. The calibration system according to claim 1, characterized in that The switch comprises: U phase contactor, V phase contactor and W phase contactor; when the U phase contactor is closed, the U phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the U phase; when the V phase contactor is closed, the V phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the V phase; when the W phase contactor is closed, the W phase of the three-phase relay is turned on, and the Hall current sensor collects the current value of the W phase.

3. The calibration system according to claim 1, characterized in that: The host computer is specifically used for: The ratio of the current output by the constant current source to the current value is calculated to obtain the current calibration coefficient.

4. The calibration system according to claim 1, characterized in that: The host computer is also used for: Determining whether the calculated current calibration coefficient is correct; If the current calibration coefficient is incorrect, the calibration process ends.

5. The calibration system according to claim 4, characterized in that The host computer is specifically used for: The current output by the constant current source is kept unchanged, and the collected current value is read from the lower computer again, and whether the current verification coefficient is correct is determined based on the current value.

6. The calibration system according to claim 4, characterized in that The host computer is specifically used for: The constant current source is controlled to change the magnitude of the current output by the constant current source, and after the constant current source changes the magnitude of the current output by the constant current source, the collected current value is read again from the lower computer, and whether the current verification coefficient is correct is determined based on the current value.

7. The calibration system according to claim 1, characterized in that: The lower computer is also used for: Read the current sampling value of the DC bus acquired by the Hall current sensor.

8. The calibration system according to claim 7, characterized in that The host computer is also used for: The current sampling value of the DC bus is read from the lower computer, and the current calibration coefficient of the DC bus is calculated according to the current sampling value of the DC bus and the current output by the constant current source.

9. The calibration system according to claim 8, characterized in that The host computer is also used for: Before calculating and obtaining the current verification coefficient of the phase and the current verification coefficient of the DC bus, the current verification coefficient of each phase and the current verification coefficient of the DC bus are set to 100%.

10. The calibration system according to claim 8, characterized in that The host computer is also used for: The calculated current verification coefficient of the phase and the current verification coefficient of the DC bus are written into a cache.

11. The calibration system according to claim 1, characterized in that: The lower computer communicates with the upper computer via a CAN bus.

12. The calibration system according to claim 1, characterized in that The host computer communicates with the constant current source via a CAN bus.

13. The calibration system according to claim 1, characterized in that The lower computer is a DSP processor.

14. The calibration system according to claim 1, characterized in that Also includes: A radiator is used to dissipate heat from the calibration system.

15. The calibration system according to claim 11, characterized in that The heat dissipation unit is a water flow type radiator.

Images