Mitigation of microcontroller restart from post-failure shutdown condition

Patent metadata

Field	Value
Publication number	US-12142909-B2
Application number	US-202117489347-A
Country	US
Kind code	B2
Filing date	Sep 29, 2021
Priority date	Aug 14, 2018
Publication date	Nov 12, 2024
Grant date	Nov 12, 2024

Abstract

Improvements to a power input circuit of an electric motor drive system are provided. The power input circuit is provided between a power source (e.g., battery), and a load (e.g., an inverter and a motor in the electric motor drive system). The power input circuit can comprise controllable switches for reverse polarity protection and isolation of the inverter under supply short circuit condition. In addition, an improvement to a power input circuit can comprise connection of a power supply (e.g., voltage regulator) to the external power source input side of a reverse polarity protection circuit in the power input circuit to mitigate against microcontroller restart from post-failure shutdown condition. Connection of a low-power diode in series with the voltage regulator also provides for reverse polarity protection.

First claim

The invention claimed is:

1. A power input circuit connected between a power source and a motor in an electric motor drive system, the power input circuit comprising:
a reverse polarity protection circuit connected across the positive terminal and the negative terminal of the power source and comprising a first switch disposed between the power source and a load comprising the motor, the first switch configured to provide reverse polarity protection from the power source; and
a voltage regulator circuit connected in parallel with the reverse polarity protection circuit and across the positive terminal and the negative terminal of the power source;
wherein the voltage regulator circuit is connected to the power source and an input side of the reverse polarity protection circuit to isolate the voltage regulator circuit from a load side voltage; and
wherein the voltage regulator comprises a 5V bus output to a microcontroller in the electric motor drive system, and the voltage regulator circuit is connected to the power source and an input side of the reverse polarity protection circuit to isolate the voltage regulator circuit from the load side voltage and prevent unwanted restart of the microcontroller by the voltage regulator circuit when a load side voltage occurs after a post-fault shutdown of the electric motor drive system.

2. The power input circuit of claim 1 , further comprising a diode connected in series with the voltage regulator, the voltage regulator circuit and the diode connected across the terminals of the power source and the diode configured to provide the voltage regulator circuit with reverse polarity protection from the power source.

3. The power input circuit of claim 1 , wherein the reverse polarity protection circuit comprises a second switch connected to the first switch and configured to prevent activation of the first switch to close and conduct power from the power source to the load during a reverse polarity condition of the power source, and to isolate the load during a short circuit condition of the power source.

4. The power input circuit of claim 1 , wherein the reverse polarity protection circuit is connected in parallel with the load, and the voltage regulator circuit is connected in parallel with the load.

5. The power input circuit of claim 3 , wherein the second switch has a voltage needed for activation to open from being closed, the second switch being configured to open and prevent activation of the first switch to close and conduct power from the power source to the load when the first switch is open during a reverse polarity condition of the power source, and to isolate the first switch from activation to close due to a load side generated voltage during a short circuit condition of the power source, when the load side generated voltage reaches the voltage needed for activation of the second switch to open.

6. The power input circuit of claim 1 , wherein the electric motor drive system is an electric power steering (EPS) system.

Assignees

• Steering Solutions Ip Holding

Inventors

• Pramod Prerit
• Kolli Nithin
• Saha Aparna
• Lowe Infane O

Classifications

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• H02H11/002

  in case of inverted polarity or connection; with switching for obtaining correct connection · CPC title

• B62D5/0481

  monitoring the steering system, e.g. failures · CPC title

• B62D5/0463

  calculating assisting torque from the motor based on driver input · CPC title

• H02H7/0833 Primary

  for electric motors with control arrangements · CPC title