参数资料
| 型号： | AD7874AQ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 4/16页 |
| 文件大小： | 0K |
| 描述： | IC DAS 12BIT 4CH 5V 28-CDIP |
| 标准包装： | 1 |
| 类型： | 数据采集系统（DAS） |
| 分辨率（位）： | 12 b |
| 采样率（每秒）： | 116k |
| 数据接口： | 并联 |
| 电压电源： | 双 ± |
| 电源电压： | ±5V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 28-CDIP（0.600"，15.24mm） |
| 供应商设备封装： | 28-CDIP |
| 包装： | 管件 |
AD7874
REV. C
–12–
APPLICATIONS
Vector Motor Control
The current drawn by a motor can be split into two compo-
nents: one produces torque and the other produces magnetic
flux. For optimal performance of the motor, these two compo-
nents should be controlled independently. In conventional
methods of controlling a three-phase motor, the current (or
voltage) supplied to the motor and the frequency of the drive are
the basic control variables. However, both the torque and flux
are functions of current (or voltage) and frequency. This cou-
pling effect can reduce the performance of the motor because,
for example, if the torque is increased by increasing the fre-
quency, the flux tends to decrease.
Vector control of an ac motor involves controlling phase in addi-
tion to drive and current frequency. Controlling the phase of the
motor requires feedback information on the position of the rotor
relative to the rotating magnetic field in the motor. Using this
information, a vector controller mathematically transforms the
three phase drive currents into separate torque and flux compo-
nents. The AD7874, with its four-channel simultaneous sam-
pling capability, is ideally suited for use in vector motor control
applications.
A block diagram of a vector motor control application using the
AD7874 is shown in Figure 17. The position of the field is de-
rived by determining the current in each phase of the motor.
Only two phase currents need to be measured because the third
can be calculated if two phases are known. Channel 1 and
Channel 2 of the AD7874 are used to digitize this information.
Simultaneous sampling is critical to maintain the relative phase
information between the two channels. A current sensing isola-
tion amplifier, transformer or Hall effect sensor is used between
the motor and the AD7874. Rotor information is obtained by
measuring the voltage from two of the inputs to the motor.
Channel 3 and Channel 4 of the AD7874 are used to obtain this
information. Once again the relative phase of the two channels
is important. A DSP microprocessor is used to perform the
mathematical transformations and control loop calculations on
the information fed back by the AD7874.
VOLTAGE
ATTENUATORS
DAC
TORQUE
SETPOINT
IN1
V
VIN4
V
IN3
V
IN2
*ADDITIONAL PINS OMITTED FOR CLARITY
TORQUE & FLUX
CONTROL LOOP
CALCULATIONS &
TWO TO THREE
PHASE
INFORMATION
TRANSFORMATION
TO TORQUE &
FLUX CURRENT
COMPONENTS
FLUX
SETPOINT
DRIVE
CIRCUITRY
ISOLATION
AMPLIFIERS
AD7874*
DSP
MICROPROCESSOR
I
C
I
B
I
A
V
B
V
A
3
PHASE
MOTOR
Figure 17. Vector Motor Control Using the AD7874
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相关代理商/技术参数 |
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| AD7874AR | 功能描述:IC DAS 12BIT 4CH LC2MOS 28-SOIC RoHS:否 类别:集成电路 (IC) >> 数据采集 - ADCs/DAC - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:50 系列:- 类型:数据采集系统（DAS） 分辨率（位）:16 b 采样率（每秒）:21.94k 数据接口:MICROWIRE?，QSPI?，串行，SPI? 电压电源:模拟和数字 电源电压:1.8 V ~ 3.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（6x6） 包装:托盘 |
| AD7874AR-REEL | 制造商:Analog Devices 功能描述:ADC Single SAR 116ksps 12-bit Parallel 28-Pin SOIC W T/R |
| AD7874AR-REEL7 | 功能描述:IC DAS 12BIT 4CH 5V 28-SOIC RoHS:否 类别:集成电路 (IC) >> 数据采集 - ADCs/DAC - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:50 系列:- 类型:数据采集系统（DAS） 分辨率（位）:16 b 采样率（每秒）:21.94k 数据接口:MICROWIRE?，QSPI?，串行，SPI? 电压电源:模拟和数字 电源电压:1.8 V ~ 3.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（6x6） 包装:托盘 |
| AD7874ARZ | 功能描述:IC DAS 12BIT 4CH 5V 28-SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - ADCs/DAC - 专用型 系列:- 产品培训模块:Data Converter Basics 标准包装:1 系列:- 类型:电机控制 分辨率（位）:12 b 采样率（每秒）:1M 数据接口:串行，并联 电压电源:单电源 电源电压:2.7 V ~ 3.6 V，4.5 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:100-TQFP 供应商设备封装:100-TQFP（14x14） 包装:剪切带 (CT) 其它名称:296-18373-1 |
| AD7874ARZ-REEL | 功能描述:IC DAS 12BIT 4CH 5V 28-SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - ADCs/DAC - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:50 系列:- 类型:数据采集系统（DAS） 分辨率（位）:16 b 采样率（每秒）:21.94k 数据接口:MICROWIRE?，QSPI?，串行，SPI? 电压电源:模拟和数字 电源电压:1.8 V ~ 3.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（6x6） 包装:托盘 |
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