MSO 4B oscilloscope brings more benchtop power analysis tools to engineers

持续测量 AC-DC 和 DC-DC 转换器的性能可能是一项极具挑战性的任务。 随着设计师努力从硅基电源转换器过渡到碳化硅 (SiC) 和氮化镓 (GaN) 等宽禁带半导体，这些挑战变得尤为棘手。电机驱动器等三相系统的设计师面临更多复杂问题。

Fortunately, they can use the latest benchtop oscilloscopes, which offer increased power and speed for power supply and motor drive analysis, with software that enables engineers to make faster, more repeatable measurements.

A more feature-rich Tektronix oscilloscope

The Tektronix 4 B Series MSO is one such oscilloscope that is equipped with a more powerful processor to speed up the analysis of power converter designers. This oscilloscope features a new user interface that is twice as responsive and provides significantly faster measurements than the previous generation of oscilloscopes. In addition, this oscilloscope is affordable and can be purchased by many professional designers.

AC-DC and DC-DC Power Supply Measurements

示波器具有自动执行关键功率测量的选项。该高级功率测量和分析 (4-PWR) 选项可以测量交流线路输入的频率、RMS 电压和电流、以及电压和电流的波峰因数。它还可以测量有功功率、无功功率和视在功率以及功率因数和相位。

The power measurement and analysis software automates the calculations to measure the switching losses of power converters.

Engineers need to make incremental changes when looking for small improvements, which requires measurements such as switching losses and magnetic losses. The software can also be used to measure the safe operating area of ​​switching devices in the circuit. All of these measurements can be accelerated by the faster processor of the 4 B Series.

Wide Bandgap Devices

For wide bandgap SiC and GaN devices, accurate evaluation of their switching losses requires a larger measurement bandgap to accommodate faster switching rates. Until recently, switching measurements on the high side of a half-bridge switching stage relative to the switch node were distorted because the high common-mode voltage signal interfered with the differential signal.

However, the 4B Series MSO oscilloscopes are compatible with a relatively new class of probes that use optical isolation to achieve a common-mode rejection ratio (CMRR) of 80 dB at 1 GHz, and even higher CMRR at lower frequencies. These IsoVu optically isolated probes can measure switching signals of 100 V/ns or faster while avoiding distortion issues caused by common-mode voltage swings.

双脉冲测试通常用于评估在接近或超过全输出的条件下，场效应晶体管 (FET) 和绝缘栅双极型晶体管 (IGBT) 在电路中的性能。

Double Pulse Test Analysis software can help designers transition to wide bandgap switching technology. This measurement tool has powerful processing capabilities that automate setup, measurements, and calculations, allowing designers to measure switching parameters and diode reverse recovery characteristics faster and easier.

Three-phase power supply and motor driver

现代电机驱动系统通常使用脉冲宽度调制 (PWM) 来控制频率，从而控制电机的速度，但频率的变化会导致难以对这些信号进行稳定测量。要想实现稳定的波形，通过人工确定滤波器和触发器的正确组合非常棘手，但对于实现一致测量却是必要的。驱动系统通常具有三相输出，这使连接和设置变得复杂。

In addition to measuring the output of the drive, it is also important to measure and evaluate the drive's input stage performance, such as harmonics, power, and power factor.

4B 系列具有更强大的性能以及内置配置和分析功能，因此是进行此类三相测量的理想选择。此前，只有高端示波器才具备此功能。

六通道可帮助解决三相问题

The output of motor drives and inverters often uses a three-wire system without a neutral conductor. The dual wattmeter method allows accurate measurement of power in these systems using only two voltage channels and two current channels on an oscilloscope. The measurement requires two voltage channels and two current channels, with the voltage channels connected to different phases and one phase used as a reference.

Three-phase analysis software can be used to achieve robust measurements of PWM motor drive outputs. This can be done with a four-channel oscilloscope. However, the input to an industrial drive is more likely to use a four-wire system with a neutral conductor. In this case, three power meters should be used, a configuration that requires six oscilloscope channels: three voltage channels and three current channels. While many oscilloscopes offer eight input channels, the 4 Series B MSO is one of the few professional-grade oscilloscopes with six analog inputs.

Like most Tektronix instruments, the 4B Series oscilloscopes have standard communication interfaces such as USB and Ethernet . These interfaces enable remote control and data access as well as test automation. The power measurements mentioned above can all be automated using a comprehensive set of fully documented programming commands. While automation programs can be written in any environment such as Matlab, C, C++ and LabVIEW, the newly introduced Python driver makes automation even easier. Learn more about the 4 Series B MSO Oscilloscope,