霍尔效应电流传感在混合动力电动汽车中的应用亚博尊贵会员
霍尔效应电流传感在混合动力电动汽车中的应用亚博尊贵会员
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Hybrid/EV Solutions
电流传感器集成电路
肖恩·米拉诺和迈克·杜格
Allegro MicroSystems, LLC
Introduction
消费者s are embracing environmentally friendly "green cars" as a result of the rising cost of fossil fuels and a growing concern for the health of the environment. Sales forecasts predict that green car sales will comprise 20%–25% of all vehicle sales by the year 2015.[1] The hybrid electric vehicle (HEV) is quickly becoming the most popular green car and by 2015 is expected to comprise approximately 12% of global vehicle sales.[1] Hybrid electric vehicles employ complex power electronic circuitry to control the flow of electric energy through the vehicle. In a single motor HEV (see figure 1) the motor acts as a drive motor in parallel with the internal combustion engine, or as a generator to charge the battery during regenerative braking.
图1. Typical HEV System Block Diagram
A typical HEV contains various systems that require electrical current sensors for maximally efficient operation; including AC motor and DC–DC converter applications. This article focuses on recent advances in Hall-effect current sensor technology and the use of unique, high bandwidth, enhanced resolution current sensors in HEV applications.
HEV电源循环
在HEV动力循环中，主蓄电池电压倒转，如图1所示，产生的交流电压施加到电机上，电机反过来驱动车轮。在再生制动过程中，交流电机还充当发电机。当再生系统启动时，电动发电机的输出被整流并转换为为为HEV蓄电池充电所需的直流电压，从而完成电源循环。如果HEV是插入式车辆，则还可以对线路电压进行整流并用于对蓄电池充电。
再生制动过程是提高混合动力汽车燃油效率的主要因素，因为制动能量（通常以热的形式浪费）被部分回收并用于给主蓄电池充电。为了给车内的低电压信息娱乐和车身控制子系统供电，通常使用DC-DC转换器将混合动力蓄电池电压（通常从300到500 V）降低到较低的直流电压。
霍尔效应电流传感的一次革命
One drawback of conventional Hall-effect sensors, when used in current sensing applications, has been a general limitation in both accuracy and output signal bandwidth. However, Allegro has developed a broad family of Hall-effect current sensor integrated circuits (ICs) that are ideally suited for HEV applications. The features and benefits of these industry-leading Allegro current sensor ICs include:
- 信号处理和封装设计创新可实现>120 kHz的输出带宽
- 目前分辨率最高,最低噪音spectral density Hall sensor ICs in the marketplace
- 专有的、占地面积小的传感器IC封装，带电流隔离
- Reduced power loss: through-hole compliant and low-resistance integrated conductor packages
- 传感器IC增益和偏置的精确工厂编程
图2depicts the wide range of proprietary package configurations in the Allegro current sensor IC family and displays the current magnitude that can be sensed using each package type.
图2。Allegro电流传感器组件
Current Sensing in Inverter Applications
典型逆变器中的三相全桥驱动器将直流电池电压转换为系统电机高效运行所需的三相交流电压（见图3）。测量逆变器相电流，所得信息通常用于控制脉宽调制（PWM）逆变器开关（通常为IGBT）。逆变器控制回路需要高带宽的电流传感器，以提高精度，并最大限度地提高电机转矩和整体电机效率。具有快速响应时间的高压侧电流传感器还可以在从电机相到系统接地节点的短路情况下启用过电流保护。快板A1360霍尔线性器件专为满足HEV逆变器应用的电压隔离、>200安培（A）负载电流和高带宽需求而定制。亚博尊贵会员
图3。（左）：DC-DC转换器充电器，（右）：三相DC-AC逆变器
这个A1360线性霍尔效应传感器通常放置在铁磁圆环的间隙中，该圆环包围电机中的每个逆变器相导体（图2）。当电流在导体中流动时，圆环通过标准的单线封装（SIP）集中产生的磁场。这个A1360Hall transducer provides an output voltage proportional to this current. The device is available in a proprietary, 1-mm thick package that reduces eddy current losses to improve sensor IC output bandwidth when compared to more conventional IC packages. Allegro SIP-based current sensor ICs have a typical output bandwidth as high as 120 kHz and offer high resolution, high accuracy performance that allows higher-speed control of the PWM switches in an inverter system. Additionally, these SIP sensor ICs offer a 3 µs output response time for IGBT overcurrent protection applications. The form factor of this solution is also much smaller than bulky current transformers. The Allegro SIP package simply provides the necessary galvanic isolation because the sensor IC output leads are not connected to the high voltage, current carrying conductors in each phase of the motor.
DC–DC转换器
电流感应范围和所需的隔离电压决定了用于DC–DC转换器的最佳Allegro电流传感器IC封装。
Current sensors in DC–DC converters are often required to sense currents down to DC frequencies. This requirement precludes the use of current transformers in fully optimized systems. Using shunt resistors in these applications is also challenging (or impossible) since the high input or output DC voltages require expensive, high common-mode input operational amplifiers. As a result of the inherent galvanic isolation of Allegro Hall-effect sensor ICs, and their ability to sense both DC current and high frequency current signals, they are a logical choice for HEVs in DC-DC converter applications.
A simplified regenerative DC–DC converter is shown in figures 1 and 3. The regenerative converter utilizes a current sensor that can operate at battery voltage levels. Accurately sensing the converter output current is a critical function as HEV battery life is extended by limiting the charge current delivered to the battery.
这个ACS714电流传感器is ideal for many lower current, subsystem DC-DC converter applications. TheACS714型is a factory trimmed, galvanically isolated sensor IC that is available in an extremely small form factor SOIC8 package with an integrated 1.2 mΩ conductor for low power loss. Additionally, the AllegroACS758设备将一个100μΩ导体和一个铁磁芯合并到一个小尺寸的、电隔离的封装中，能够感测50到200 a的电流。可以使用前面提到的基于SIP的环形配置感测200 a以上的电流。所有这些Allegro解决方案都提供业界领先的高带宽输出性能和卓越的电流分辨率能力。
Summary
Allegro’s latest generation Hall-effect current sensor IC technology offers significant advantages in sensing both AC and DC currents in HEVs. Hall current sensors have inherent galvanic isolation for high side current sensing, and offer low power loss in high efficiency HEV applications. Recent improvements in Hall IC technology by Allegro have resulted in the development of industry leading high bandwidth, high resolution current sensor ICs that are ideally suited for use in HEV inverter and DC–DC converter applications.
References
文章发表于Power Systems Design Europe，2010年7月/8月。经允许转载。
[1]"Global Automotive Industry Outlook 2009: Impact of Economic Slowdown on the Future of Auto Sales and Production," Frost & Sullivan, 2009, p. 31, online edition accessed June 2010,http://www.frost.com/prod/servlet/report-homepage.pag?repid=M3A1-01-00-00-00.
参考号：AN296075