Hybrid Car Inverter – Types, Function, & Common Issues

A hybrid car inverter is an essential energy management system component in every plug-in hybrid electric vehicle (PHEV). The technology behind electric vehicles and hybrid cars has been significantly streamlined. Batteries that used to take several hours to charge fully now take some minutes. Fast battery charging requires several components that can handle more power and keep the vehicle at a safe operating temperature. In hybrid cars, one of these components is the inverter. This article will explain the types of inverters used in electric vehicles and hybrid car inverter problems. You'll also know the repair cost. But first, what is a hybrid inverter? What is a hybrid inverter and its types? The inverter in hybrid cars is an essential component that connects the car battery (AC) to the car motor (DC volt). The motor has three phases, while the battery has two. So, it is impossible to connect them together without the inverter. Types There are three different types of hybrid car inverter. They are the voltage source inverter, current source inverter, and dual inverter. Voltage source inverter The voltage source inverter (VSI) is the most common type of hybrid car inverter. It is also called voltage-fed inverters (VFI). Most hybrid car manufacturers use this type of inverter. It converts high-voltage direct current (DC) from the battery to a three-phase alternating current (AC) for the electric motor. Current source inverter A current source inverter (CSI) is a type of inverter that converts direct current from its input to an equivalent alternating current. It's also known as a current-fed inverter (CFI). In CSI, the current supplied to the input is a stiff direct current instead of a direct current voltage. Dual inverters As the name implies, this is a type of hybrid inverter that consists of two separate units. One of the inverters is responsible for driving the front wheel, while the other inverter drives the rear wheels. The dual inverters enable even power distribution between the front and rear wheels. What are the Functions of a Hybrid car Inverter? In hybrid vehicles, we have the battery and the electric motor. The battery runs on direct current (DC) voltage with two-phase, while the electric motor runs on alternating current (AC) voltage with three-phase. These two components cannot be connected together without first converting the voltages. The hybrid system needs a component that can convert DC to AC and AC to DC. Here’s where the inverter comes in. The hybrid inverters change the DC voltage to AC voltage using transistors and AC voltage to DC voltage using rectifiers and diodes. Primarily, the function of the hybrid inverters is to change alternating current (AC) to direct current (DC) and direct current (DC) to alternating current (AC). Inside the inverter, there's another component called the converter, which changes the value of the voltage. What does the converter do? Hybrid converter functions as a voltage value exchanger. Here's what I mean; in hybrid cars, we have 12 volts electrical systems, otherwise called the auxiliary system. So, the vehicle needs a 12-volt battery with negative and positive terminals. The negative terminal is grounded to the vehicle chassis, and the positive terminal is connected to the converter. Hybrid vehicles do not have alternators to charge the battery. So, the converter collects power from the DC high voltage battery with around 200 volts and changes it to auxiliary power. In other words, the converter converts the 200-voltage current from the battery pack to 14.5 volts to charge the 12-volt battery. 14.5 volts is the normal voltage the alternator in a traditional vehicle uses to charge a 12-volt battery. Altogether, the hybrid car inverter converter converts direct current to alternating current and also exchanges the voltage value coming from the Hybrid battery pack to the auxiliary system. Without this component, the voltage from the battery pack will damage all the 12-volt components on the auxiliary system. And, it’ll be impossible for power to transmit from the hybrid battery pack to the electric motor. Hybrid car Inverter Common Problems Even in a world full of gearheads, it's tricky to determine when you have a dead hybrid car inverter. But I'll try to break down a faulty inverter's signs and diagnosis codes to make it easier for you. The car won't go into drive or reverse. The most common scenario we encountered in our garage is where the car won't go into reverse or drive. If your hybrid car starts, has several warning lights on the dashboard, and won't go into drive or reverse, it's likely an inverter issue. If the inverter is the root cost, clearing the warning lights with a scan tool will let the car enter drive and reserve gear. You can drive the vehicle after clearing the warning lights, but the issue will happen once you turn off and start the car again. This is a common trick most hybrid car owners, especially Prius owners, use to drive their vehicle to a mechanic. Some folks continue using this trick until they have money to fix the inverter. Voltage isolation fault. Another common inverter problem is the voltage isolation fault. This problem has no unique symptoms. However, the car computer will log error code P0AA6. This error can also mean a voltage leak on the transaxle, hybrid battery, and AC compressor. Therefore, you have to run more diagnostics to track where the voltage leaks from. You have to look for a detailed code, also called a subcode. You can only pull out the subcodes with a high-end diagnostic scan tool. Cheap scan tools won't do the job. The car computer will usually log 526, but that's not what you should look for. There should be other subcodes like 614, 613, 612, or 611. A subcode 614 shows the voltage leak is from the inverter. If you only pull subcode 526, turn off and on the vehicle and rescan the car again. Repeat this step until you see any of the above subcodes. Overheating inverter. Lastly, another common problem with hybrid inverters is overheating. If your car is stalling and letting it cool down before driving resolves the problem, you have an overheating inverter. In this case, diagnose the vehicle using an OBD2 scan tool. A P0A93 means the inverter pump is faulty and should be replaced. Other error codes like a P0A78 and a P0A94 are quite tricky. But they typically mean the entire inverter should be replaced. The hybrid inverter repair cost Several factors influence hybrid car inverter repair cost. These factors include warranty coverage, type of repair, car make and model, and the mechanic doing the repair. On average, repairing a hybrid car inverter costs between $700 and $2,200. The exact price depends on your type of inverter and the damaged component. The dealership or mechanic may demand you replace the entire inverter if the damage is severe. Hybrid and EV inverters cost between $4,000 and $10,000 for replacement, depending on your vehicle's make and model. Final Words In summary, hybrid and electric car inverters are essential components of both EV and PHEV cars. The purpose of the inverter is to change AC current to DC current and DC current to AC current. While a failing hybrid car inverter is not easy to identify, I have explained the common inverter scenarios I have experienced in my garage. If you notice any of the outlined problems, follow the guidelines above to confirm if the inverter is bad. If you can't roll up your sleeves and track down the root cause of the problem, contact your mechanic or dealership.