Keeping AM Radio in Electric Vehicles Using Ansys EMC Plus

The race is on to find a way for electric vehicles and AM radio to live in harmony.

Roughly 47 million Americans listen to AM radio, with a majority of listeners living in rural areas of the country. For these Americans, AM radio is sometimes the only reliable way to get emergency notifications. Despite this, some car manufacturers have started phasing out access to AM radio in newer model electric vehicles.

Car makers cite poor performance of AM radio for the move. The subpar signal is the result of the electric current driving the battery and motor. The high current moving through the vehicle can create inductance which can transfer back into the antenna system. This causes unwanted static across the entire AM band, but especially in the lower portion between 500 to 700 kHz. It is not just the motor and battery that could be to blame, but even possibly power windows or power mirrors that are not designed or shielded correctly.

Manufacturers that have already removed AM radio from vehicles include BMW, Mazda, Telsa, Volkswagen, and Volvo. Ford initially planned to remove AM radio capabilities from its electric and gas cars in 2024, but reversed course. Ford CEO Jim Farley announced the decision to keep AM in May 2023. He posted on LinkedIn saying “After speaking with policy leaders about the importance of AM broadcast radio as a part of the emergency alert system, we’ve decided to include it on all 2024 Ford and Lincoln vehicles.” Ford will be offering a software update for vehicle owners that currently do not have AM broadcast capability.

Concerns about the lack of AM radio have come from state and federal leaders. Attorneys General in 16 states have expressed concerns about eliminating AM radio. In a June 2023 letter to the Electric Drive Transportation Association and the Zero Emission Transportation Association, they say some residents in their states only have access to AM radio and that AM is critical to keeping rural communities safe during an emergency. In the letter, the AG’s write “Without access to their main consumers- automobile owners- AM stations, and the lifesaving signals they provide, might cease to exist.”

One way to prevent unwanted noise in the AM signal is proper shielding. Volkswagen has looked into shielding cables but says that it added too much weight that drags down an EV’s range. Stellantis, the parent company of Chrysler and Jeep, is using shielding as a way to fix the problem. The company says future vehicles will use shielded cables and the radio receiver will be moved further away from the motor.

Developing a solution after a prototype has been built is not only costly but time consuming. The ideal solution is to find interference problems during the design phase. Ansys EMC Plus (formerly EMA3D® Cable) allows designers to determine if there will be any electromagnetic compatibility or interference problems before a physical prototype is ever built.

EMC Plus is a 3D Finite-Difference Time-Domain (FDTD) solver with a multi-conductor transmission line solver. The two electromagnetic solvers co-simulate to allow for platform-level EMC modeling, including electronic devices, automobiles, or aircraft.

Specifically, when designing automobiles, EMC Plus has the power to analyze:

  • Radiated coupling to cables
  • Radiated emissions from cables
  • Coupling through shields
  • EMI cross-talk between cables
  • Current return network optimization
  • Cable signal integrity

Meshing in EMC Plus is fast and never fails, even with imperfections in the CAD geometry. Users are able to quickly define the contents of what is being analyzed with a few clicks of the mouse, making it faster to start the simulation. EMC Plus is in a league of its own, with the capability to simulate thousands of cables at the same time.

Recently EMA worked with Lightning eMotors to simulate EMC in one of its new products. Lighting eMotors produces commercial EVs and called EMA for help on its new mobile battery vehicle charger.

Lightning eMotors mobile battery vehicle charger being tested in EMC Plus.

Using EMC Plus, EMA was able to determine that an EMC/EMI threat was present. Knowing that a threat existed, EMA tested several possible solutions to find the best design. The entire process took less than two months of calendar time.

To learn more about this project, you can read the White Paper here: Lighting eMotors White Paper.

The rise of AM radio became widespread in the 1920s, changing the way Americans received information and entertainment. Families would sit together listening to live baseball and football games, music, and President Franklin D. Roosevelt’s fireside chats. Currently there are nearly 4,200 AM stations across the U.S.

AM radio may not be as popular today as it was in the past, but it still has a place in many Americans’ lives. With early testing and simulation with EMC Plus, car manufacturers can make sure EVs and AM radio can co-habitat in the body of a vehicle.

EMA maintains EMC Plus, which is sold exclusively through Ansys. To learn more about EMC Plus and its capabilities, just click here. If you’re looking for help completing EMC testing, reach out to EMA by clicking here.