外文文献翻译(成品).doc

本科毕业设计（论文）外文翻译译文学生姓名： 年拾军 院 （系）： 电子工程学院 专业班级： 电气1102 指导教师： 张建军 完成日期： 2015 年 月 日 电机控制软件的例子起止页码：9-16出版日期（期刊号）：出版单位：例5 交流试验感应电动机前面的例子都集中在小型低压电动机。直流电机和无刷直流电机低压电机驱动系统提供有竞争力的解决方案。交流感应电机通常只用于离线应用。该c8051f3xx家庭可以用来提供恒定的V / Hz分马力电机控制具有成本效益的解决方案。分马力电机的范围从1 / 4到3 / 4马力和正常工作电压为110伏到240伏。交流感应电动机可用于范围广泛的不同性能要求的应用。最简单的控制方法，称为恒定的V / Hz的控制。这种控制方法用于调速或调速交流感应电机驱动系统。交流感应电动机采用恒定的V / Hz的控制可用于风扇，鼓风机，空气处理，泵，潜水泵，压缩机。一个C8051F3XX单片机可以用来提供这些应用程序的一个低成本的解决方案。在业绩的另一端，矢量控制可用于提供一个高性能的运动控制系统，达到或超过直流伺服驱动器的性能。矢量控制通常需要使用一个DSP来执行复杂的矩阵代数变换。矢量控制知识的吸引力诱惑的工程师，真的不需要的性能应用程序使用矢量控制。然而，成本意识的系统设计师会欣赏这个恒定的V / Hz的系统成本更低。简化原理图如5交流感应电机如图7所示。一个晶体管三相桥是用来驱动交流异步电动机。功率晶体管可能功率MOSFET和绝缘栅双极晶体管（IGBT）。IGBT通常会提供较低的功率损耗为230 VAC应用大于1 / 4惠普。P0.0，P0.1，和焊F221用于控制三相桥栅极驱动。图7 交流感应电机驱动高电压集成电路可用于提供一个简单的，低成本的零件计数，栅极驱动。死亡时间是需要防止交叉传导和增加功率损耗。开关时间是由功率晶体管的性能和电路的寄生效应有限。死区时间也必须考虑在开启和关闭任何不匹配的系统延迟。高电压集成电路可与内置的很少或没有额外成本的死区时间。IR2103S是一个600 V半桥栅极驱动器与一个固定的死区时间为520 ns和3 V兼容的输入。IR2104S提供了相同的功能，再加上一个低电平关机，禁用输出。关机功能更复杂的系统中是非常有用的用于启动和故障保护。这个例子提供了简单的开环V / Hz控制交流异步电动机用C8051F300单片机。单片机读取速度控制电位器的值并产生三相正弦波PWM驱动器所需的功率晶体管。三PCA模块配置为8位PWM用于产生三相PWM。三相PWM波形如图8所示。 图8 三相PWMcex0 PCA0输出，cex1，和cex2通过写0xC0的xbr1 SFR启用。的xbr0 SFR清不跳过任何引脚。这个配置P0.0，P0.1 PCA0输出，并规定。第一三输出P0.0P0.2配置为推挽输出写0x07的p0mdout SFR。p0.6配置为模拟速度控制输入。当横梁启用，这将使三输出。三PCA模块被配置为通过写0x42各自捕获/比较寄存器的位模式PWM模式。PWM高倍被初始化为50%。在启动时，使用P0.2通过弱上拉默认最初被拉高。下拉电阻是使用武力输出低电平启动。这取决于较低的晶体管和费用用于高侧栅极驱动的自举电源。PCA在横梁启用初始化。当横梁被初始化50%波形将出现在输出P0.0通过规定。主循环读取ADC采用平均并存储在全局变量的值电压。所有的正弦波生成和更新是使用中断。定时器T0被配置为16位计数器方式1。定时器使用24.5 MHz的系统时钟频率除以四。启动定时器TF0和设置为1力初始中断。定时器中断服务程序timer_isr()是用来产生周期性的中断一段时间约1毫秒。建立之后，下一个中断，该timer_isr()会叫update()功能。update()功能更新的基于采样的正弦波PWM占空比的三。的值是基于关系说明计算公式1。首先，全局变量伏复制到局部变量。变量是欧米茄缩放，值寄存器对应于约1 Hz的正弦频率。欧米茄的价值是通过添加欧米茄全局变量和集成。和是一个16位的无符号整型数据类型。和上面的字节复制到。 V = dt = 金额=金额+=金额/ 256方程18位变量传递到sinewave()功能。返回的值从sinewave()函数存储在pca0cph0。这套cex0占空比。其他两个PWM用和+加0x55 0xAA更新。这产生三个正弦调制信号的120分开。sinewave()函数使用正弦查找表 含256签署了8位值。正弦 值对应的乘以伏特变。在一个8位存储变量的产品最重要的字节。0X80偏移加到提供正弦波输出值为50%。例6 PWM采用高速输出模式PCA的8位PWM模式提供了足够的分辨率对于大多数小型电机驱动应用。PWM频率一般选为上面的听觉范围。小型电动机的优化PWM频率在16至24 kHz范围内。积分马力交流感应电机通常采用较低的开关频率，以降低开关损耗。24千赫的频率是最适合小电机驱动。8位PWM频率可以设置为8，24，或96千赫操作时从一个24.5 MHz的系统时钟频率。16或19.1千赫可以用T0溢出为PCA的时钟源得到的8位PWM频率。一些应用程序可能需要超过8位以上的分辨率。更高的分辨率可达到优于1%使用直流或直流无刷电机调速。交流感应电机系统需要大于100到1的速度范围也可能需要更高的分辨率。更高的分辨率和任意PWM频率可以通过使用高速的输出获得（HSO）的可编程计数器阵列模式产生一个PWM信号。HSO模式可以产生高达16位的分辨率和40 ns定时PWM波形的边缘。这对应于10.25位或0.0816%有效分辨率在20千赫。权衡的是，软件延时限制最低时高时低。单片机必须有足够的时间来中断当前进程写新的值到输出比较之前的下边缘计划发生寄存器。潜伏期可由高优先级分配PCA0最小化，缓存的边缘的时序数据，并使用备用寄存器设置为中断服务程序。的CPU消耗很大一部分可用的处理能力，频繁的PCA中断服务。软件例如6读取速度控制电位器的值并输出20 kHz PWM波形对P0.0。系统时钟，ADC，和端口初始化实例1相同。功能配置的pca0_init() PCA使用系统时钟和配置模块0高速输出模式。PCA初始化也安排第一PCA中断。两个全局变量nextedge和周期由PCA用于中断服务程序。nextedge用来缓存数据的一个边缘的边缘时间提前减少延迟。全球比特周期是用来保持轨道的边缘发生下。由于HSO模式切换输出，软件标志位是必需的。使用一个标志位比投票更强大的输出引脚的状态，因为它是独立的比较匹配。预处理器宏延迟设置的值就大于更新延迟提供可靠的操作。预处理器宏计算计算期和htspan。高时间跨度htspan是期负延迟的两倍。主回路采用平均ADC的民意调查。从ADC值乘以所需的时间跨度htspan。该产品是通过增加延迟，然后递增。最终的结果是存储在一个全局变量hitime。临时变量x和y是用来计算中间值。缩放的操作需要一个长整型数据类型。最后的结果是16位。全局变量hitime不宜用于中间计算。中断服务程序可以拾取新的价值在任何时间，将PWM用荒谬的价值观。PCA0中断也暂时停用的hitime更新期间确保中断不会发生直到字节已更新。PCA中断服务程序pca0_isr()首先更新pca0cpx0寄存器，然后清除PCA0模块0捕获/比较标志ccf0。一旦标志被清除，它是安全的下一个中断发生。根据比特周期的状态，nextedge递增hitime或时间减去hitime。的HSO PWM比较显示与图9中的8位PWM。为HSO PWM的频率正好20千赫和最小的高时间是1.8s，频率为8位PWM是24千赫和最小的高时间为160 ns。图9 最小的高时间比较例如7-center-aligned PWM这个例子演示了如何使用PCA高速输出模式，产生中心对齐PWM波形的死区时间。中心对齐PWM死区时间可用于直流或交流感应电机，无刷直流电机。直流和无刷直流电机需要主动制动必须使用PWM方案，或者打开顶部和底部的晶体管。电机提供了积极和消极的正向和反向的方向称为伺服电机或四象限驱动转矩控制。伺服电机也需要脉冲宽度调制的上部和下部晶体管。交流感应电机都使用这种类型的PWM方案产生正弦波。当脉宽调制的上部和下部晶体管，死区时间的上部和下部晶体管之间需要激活。死区时间的函数可以由单片机或集成到栅极驱动。采用中心对齐PWM有好处。它是生成的必要死的时候很容易。死区时间的互补PWM信号可以通过对第一信号的时候加入少量和反相得到。采用中心对齐的波形也有加倍的阶段和降低纹波电流频率之间的利益。这对于低电感大电机尤为重要。所需的中心对齐的波形如图10所示。这个时期是相对于顶部的PWM信号的高时间计量中心。当多个PWM通道的使用，所有的信号都是对波形的中心对齐。顶部和底部的PWM信号，如图10所示是高电平。顶部和底部的信号在死区时间是不活动的。图10 中心对齐PWM信号三PCA模块用于产生所需波形。一个模块作为主。主模块是唯一的模块产生中断。主通道产生占空比为50%的波形。在高倍和其他渠道lowtimes中心与主通道，如图11所示的上升和下降边缘对齐。在F300端口I/O引脚分配类似的例子5。销跳过SFR xbr0清除不销的优先任务跳过横杆。的xbr1 SFR初始化为输出cex0，cex1，和cex2。价值p0mdout 0x07写入配置P0.0，P0.1，P0.2为推挽输出。主回路为例6相同。的pca0_init()函数初始化所有三通道高速输出模式。中断只在模块0启用。PCA初始化函数安排第一中断和50%占空比的下边缘。所有信号的相对极性的初始化定义。规定是倒置的因为它没有一个边缘定于前半周期。PCA中断服务程序pca0_isr()类似例子7。三16位pca0cp比较特殊功能寄存器必须被更新之前的中断标志被清除。潜伏期的宏观价值必须增加考虑到额外的指令。nextedge全局变量的计算三个模块。计算是根据国家不同的周期点。中心对齐模块的下边缘值计算模块。如果周期是1，中心对齐nextedge1和nextedge2首先通过增加nextedge0计算，然后添加或减去hitime nextedge0，然后加上或减去死时间。如果周期是0，nextedge1和nextedge2通过添加或减去hitime nextedge0计算，加上或减去死区时间，并增加nextedge0。最小脉冲宽度加一半的潜伏期缩短。这将centeraligned波形稍微使边缘与至少一条件主通道对齐。图11 中心对齐PWM波形测量中心对齐PWM波形如图11所示。顶部的波形是P0.0主通道输出。范围是触发了主通道。中间和底部的波形和规定时。这些信号可以用来驱动半桥的上下管。时间配置逆变栅极驱动器。P0.1和P0.2从未在同一时间低。有上升沿和P0.1 P0.2下降沿之间有限的死区时间。在F300三PCA模块，可以被用来提供两个互补的中心对齐波形的死区时间。两个互补的PWM波形，足以使用半桥直流电机驱动。这提供了有效制动和同步整流。一个半桥驱动电机的简化框图如图12所示。图12 半桥直流传动一个I/O引脚可以通过移动的主渠道cex2配置横梁只输出cex0和cex1保存。主控模块输出的调试是非常有用的，但不可能在一些系统要求。有5的F-310 PCA模块可以用来生成四中心对齐PWM波形的死区时间。四中心对齐PWM波形可用于驱动直流伺服电机如图13所示。图13 直流伺服驱动例如8-quadrature解码,闭环速度控制需要位置反馈。有许多不同种类的位置传感器。常见的例子是光学编码器，霍尔编码器和电位器，转速表。本软件的示例演示最常用的位置传感器的低成本解决方案：光学正交编码器。光学编码器使用的半导体光电探测器和LED检测在反射盘碟或暗带槽。单通道光学编码器提供速度反馈但不能检测电机转动方向。双通道正交编码器能够提供的速度和方向。正交解码软件可以结合使用例2或中心对齐PWM用于例7伺服定位应用的直流电机控制软件。这提供了闭环电机控制来减少外部元件数量，降低系统成本的集成解决方案。两输出正交编码器，CHA和CHB，90的相位，如图14所示。如果电机转动的方向，茶将导致慢性乙型肝炎。如果电机转动方向相反，CHB将领先的茶。旋转方向可通过采取独家或两信号检测。以异或ChA和ChB的结果是由字母T和F在图14所示。当电机转动的方向，对茶的任何边缘检测后，茶和CHB异或是真的。对慢性乙型肝炎的任何边缘检测后，在车的前进方向，茶异或CHB将假。 图14 正交解码操作使用此信息，一个简单的算法可以获得使用边沿触发中断事件。在茶的边缘中断，位置应递增如果茶异或CB是真的，如果错误或递减。相反，在CHB边缘中断位置应递增我F茶异或CHB是假的，如果是真的或者递减。硬件配置的软件实例8要求正交编码器茶被接P0.0和P0.1 CHB连接。上拉电阻是最典型的正交编码器所需。一些编码器指定源仅几个微安。这些也需要上拉电阻。P0默认弱上拉通常不足以驱动一个合适的上升时间的编码器信号的高。确保正交编码器采用3 V CMOS逻辑兼容。大多数编码器的集电极开路输出应该与一个上拉电阻为3 V的上拉电阻值应降低到保持吸收电流大致相同的值。编码器还需要一个电压供电的LED和内部电路。一些编码器可能需要调节5 V电源。然而，该定制开路集电极输出仍然可以使用上拉到3 V电源。该软件为例8使用UART与ASCII终端显示的正交编码器的位置。位置存储在全局变量的位置。位置是由两个中断服务例程的外部中断INT0和INT1更新。UART的启用和配置为推挽输出P0.4。P0.0和P0.1不作为预防措施。这将是任何其他外设在横梁启用所需的。外部中断INT0和INT1初始化函数eint_init()配置使用P0.0和P0.1分别。两INT0和INT1配置为边缘激活中断。每个通道的初始触发极性是通过轮询P0.0和P0.1测定。外部中断为高优先级和启用。外部中断服务例程是相同的除了中断标志，分别改变极性位，和计数方向。第一位是触发极性切换。然后一个嵌套的ifelse语句是用来测试的极性位的状态。对于INT0，如果极性位是正确或是错误的极性位，位置将递增。否则，该职位将减少。为INT1，如果极性位是正确或是错误的极性位，位置将减少。否则，该职位将增加。这是一个逻辑异或函数等价的。该实现使用简单的一些测试和非常代码效率。图15 正交解码测量一个正交编码器测得的波形如图15所示。这种类型的正交解码使用的中断是一个可行的解决方案到约50000次/秒的速度。的每秒计数数的脉冲每秒四次。在每个脉冲四边。这对于一个中速电机适合（8000 rpm）与低分辨率编码器（100 PPR）或低速（1500转/分）和高分辨率编码器（500 PPR）。这种性能范围涵盖许多消费者和汽车应用。高性能工业伺服驱动器通常需要更高的计数率高达1000000计数/秒。这些类型的应用程序将需要一个基于硬件的正交解码器的接口。MOTOR CONTROL SOFTWARE EXAMPLES作者：起止页码：9-16出版日期（期刊号）：出版单位：Example 5AC Induction MotorThe previous examples have focused on small low-volt-age motors. DC motors and BLDC motors offercompetitive solutions for low-voltage motor drive sys-tems. AC Induction motors are typically used only in off-line applications. The C8051F3xx family may be used to provide a cost-effective solution for constant V/Hzcontrol of Fractional Horsepower motors. Fractional Horsepower motors range from 1/4 to 3/4 horsepower and normally have an operating voltage of 110 V AC to240 V AC .AC Induction motors can be used for a wide range of applications with radically different performance requirements. The simplest control method is called constant V/Hz control. This control methodology is used for variable speed or adjustable speed AC induction motor drive systems. AC inductions motors using constant V/Hz control can be used for fans, blowers, air handlers, pumps, submersible pumps, and compressors. A C8051F3xx MCU can be used to provide a low-cost solution for these applications.At the other end of the performance spectrum, vector control may be used to provide a high-performance motion control system that meets or exceeds the performance of a DC servo drive. Vector control normally requires the use of a DSP to perform complex matrix algebra transforms. The intellectual appeal of Vector control tempts engineers to use vector control in applications that do not really require the performance. However the cost-conscious system designer will appreciate much lower cost of the constant V/Hz system.The simplified schematic for Example 5 AC Induction motor is shown in Figure 7. A three-phase transistor bridge is used to drive the AC Induction motor. The power transistors might be power MOSFETs or insulated gate bipolar transistors (IGBTs). IGBTs will usually provide lower power losses for 230 V AC applications greater than 1/4 HP. P0.0, P0.1, and P0.3 are used to control the gate drive of the three-phase bridge.High-Voltage ICs may be used to provide a simple, low parts count, cost-effective gate drive. Dead-time is required to prevent cross-conduction and increased power losses. The switching time is limited by the performance of the power transistors and the circuit parasitics. The dead-time must also account for any mismatch in the turn-on and turn-off delay of the system. High-voltage ICs are available with built in dead-time for little or no additional cost. The IR2103S is a 600 V half-bridge gate driver with a fixed dead-time of 520 ns and 3 V compatible inputs. The IR2104S provides the same features plus an active low shut-down that disables both outputs. The shut- down feature is very useful in more complex systems for both start-up and fault protection. This example provides simple open loop V/Hz control for AC Induction motors using the C8051F300 MCU. The MCU reads the value of a speed control potentiometer and generates the three-phase sine wave PWM required to drive the power transistors. Three PCA modules configured for 8-bit PWM are used to generate three-phase PWM. The three-phase PWM waveforms are shown in Figure 8.Figure 8. Three-Phase PWMPCA0 outputs CEX0, CEX1, and CEX2 are enabled by writing 0xC0 to the XBR1 SFR. The XBR0 SFR is cleared to not skip any pins. This configures the PCA0 outputs on P0.0, P0.1, and P0.2. The first three outputs P0.0P0.2 are configured as push-pull outputs by writing 0x07 to the P0MDOUT SFR. P0.6 is configured as input for the analog speed control. When the crossbar is enabled this will enable the three outputs.All three PCA modules are configured for 8-bit PWM mode by writing 0x42 to their respective capture/ compare mode registers. The PWM high times are initialized to 50%.At startup, P0.0P0.2 will be initially pulled high by the weak pullups by default. Pulldown resistors are used force the output low at start-up. This turns on the lower transistors and charges the bootstrap supply used for the high-side gate drive. The PCA is initialized before the crossbar is enabled. When the crossbar is initialized a 50% waveform will appear on outputs P0.0 through P0.2.The main loop reads the ADC using averaging and stores the value in the global variable Volts . All sine wave generation and updating is done using interrupts. Timer T0 is configured for 16-bit counter mode 1. The timer uses the 24.5 MHz SYSCLK divided by four. The timer is started and TF0 is set to a 1 to force an initial interrupt.The Timer Interrupt Service Routine Timer_ISR() is used to generate a periodic interrupt with a period of about 1 ms. After setting up the next interrupt, the Timer_ISR() will call the Update() function. The Update() function updates the three PWM duty cycles based on a sampled sine wave. The value of theta is calculated based on the relationships illustrated in Equation 1. First the global variable Volts is copied to the local variable omega . The variable omega is scaled so that a value of 0x04 corresponds to a sine frequency of about 1 Hz. The value of omega is integrated by adding omega to the global variable Sum . Sum is a 16-bit unsigned int data type. The upper byte of Sum is copied into theta.V= t d= Sum = Sum + omegatheta = Sum / 256Equation 1The 8-bit variable theta is passed to the sineWave() function. The value returned from the sineWave() function is stored in PCA0CPH0. This sets the duty cycle of CEX0. The other two PWMs are updated using theta plus 0x55 and theta plus 0xAA. This generates three sine modulate PWM signals 120 apart.The sineWave() function uses the sine look-up table containing 256 signed 8-bit values. The sine value corresponding to theta is multiplied by the Volts variable. The most significant byte of the product stored nin an 8-bit variable. An offset of 0x80 is added to the output value to provide a sine wave centered about 50%.Example 6PWM using High-Speed Output ModeThe 8-bit PWM mode of the PCA provides sufficient resolution for most small motor drive applications. The PWM frequency is normally chosen to be just above the audible range. The optimum PWM frequency for small motors is in the range of 16 to 24 kHz. Integral-Horsepower AC Induction motors often employ lower switching frequencies to reduce switching losses. The 24 kHz frequency is suitable for most small motor drives.The 8-bit PWM frequency can be set to 8, 24, or 96 kHz when operating from a system clock frequency of 24.5 MHz. An 8-bit PWM frequency of 16.0 or 19.1 kHz may be obtained by using T0 overflow as the PCA clock source.Some applications may require more resolution than 8 bits. Higher resolution may be required to achieve speed regulation of better than 1% using DC or BLDC motors. AC Induction motor systems that require greater than 100 to 1 speed range may also require higher resolution.Higher resolutions and arbitrary PWM frequencies can be obtained by using the high-speed output (HSO) mode of the programmable counter array to generate a PWM signal. The HSO mode can be used to generate PWM waveforms with up to 16-bit resolutions and 40 ns edge timing. This corresponds to an effective resolution of 10.25 bits or 0.0816% at 20.0 kHz.The trade-off is that the software latency limits the minimum high-time and low-time. The MCU must have sufficient time to interrupt the current process and write the new values to the output compare registers before the next edge is scheduled to occur. The latency can be minimized by assigning the PCA0 to high priority, caching the edge timing data, and using an alternate register set for the interrupt service routine. The CPU expends a significant portion of its available processing capability servicing the frequent PCA interrupts.The software for Example 6 reads the value of the speed control potentiometer and outputs a 20.0 kHz PWM waveform on P0.0. The system clock, ADC, and port initialization are identical to Example 1. The PCA0_Init() function configures the PCA to use the system clock and configures Module 0 for high-speed output mode. The PCA initialization also schedules the first PCA interrupt.Two global variables NextEdge and cycle are used by the PCA0 Interrupt service routine. NextEdge is used to cache the edge timing data one edge ahead of time to reduce latency. The global bit cycle is used to keep track of which edge is to occur next. Since the HSO mode will toggle the output, a software flag bit is required. Using a flag bit is more robust than polling the output pin state because it is independent of compare matching.The preprocessor macro LATENCY is set to a value just greater than the update latency to provide reliable operation. Preprocessor macro calculations are used to calculate PERIOD and HTSPAN. The high-time span HTSPAN is the PERIOD minus two times LATENCY.The main loop polls the ADC using averaging. The value from the ADC is multiplied by the desired high- time span HTSPAN. The product is then incremented by adding LATENCY. The final result is then stored in a global variable HiTime . Temporary variables x and y are used to calculate the intermediate values. The scaling operation requires a long int data type. The final result is 16-bits. The global variable HiTime should not be used for intermediate calculations. The interrupt service routine might pickup the new value at any time and would use nonsensical values for the PWM. The PCA0 interrupt is also temporarily disabled during the HiTime update to ensure that an interrupt does not occur until both bytes have been updated.The PCA interrupt service routine PCA0_ISR() first updates the PCA0CPx0 registers and then clears the PCA0 Module 0 capture/compare flag CCF0. Once the flag has been cleared, it is safe for the next interrupt to occur. Depending on the state of the cycle bit, the NextEdge is incremented by HiTime or Period minus HiTime .A comparison of the HSO PWM is shown versus the 8-bit PWM in Figure 9. The frequency for the HSO PWM is exactly 20 kHz and the minimum high time is 1.8 s. The frequency for the 8-bit PWM is 24 kHz and the minimum high-time is 160 ns.Figure 9. Minimum High-Time ComparisonExample 7Center-aligned PWMThis example demonstrates how to use the PCA high-speed output mode to generate center-aligned PWM waveforms with dead-time. Center-aligned PWM with dead-time may be used for DC, BLDC, or AC induction motors. DC and BLDC motors that require active braking must use a PWM scheme that alternatively turns on the top and bottom transistors. Motors that provide positive and negative torque control in both forward and reverse directions are called servo motors or four-quadrant drives. Servo motors also require pulse-width modulating both upper and lower transistors. AC Induction motors always use this type of PWM scheme to generate sine waves. When pulse-width modulating both upper and lower transistors,dead-time is required between the activation of the upper and lower transistors. The dead-time function may be performed by the MCU or integrated into the gate drive.Using center-aligned PWM has benefits. It is very easy to generate the required dead-time. The complementary PWM signal with dead-time may be obtained by adding a small number to the high-time of the first signal and inverting. Using center-aligned waveforms also has the benefit of doubling t